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Purpose
The complication of patellofemoral compartment was quite often in total knee arthroplasty. One of the impotant factors in these complications would be the femoral component rotation in TKA. To determine the rotation of the femoral component, the reference of the surgical epicondylar axis (SEA), posterior condylar axis (PCA), AP axis with three dimensional model achieved from computed tomography data were considered. There are some limitations with pre-oprerative CT-based planning such as radio exposure, cost, time and detection of the depth of cartilage. We evaluate the determination of the femoral component rotation with image-free registration method to compare with three-dimensional template system.
Material and Methods
Thirty six knees were evaluated to determine the femoral component rotation. The reference points were marked to measure the PCA (posterior condylar axis), SEA (surgical transepicondylar axis), and APA (anteroposterior axis, Whiteside line) intra-operatively and calculated the angle from PCA to SEA and PCA to APA with Image free navigation system (BrainLAB). Those knees were preoperatively evaluated the angle deviation from SEA to PCA with three dimensional template system. These angle deviations, which suggested the femoral component rotation obtained from preoperative template system, were statistically compared with the femoral rotation angle in clinical situation.
Accurate in vivo knee joint contact forces are required for joint simulator protocols and finite element models during the development and testing of total knee replacements (Varadarajan et al., 2008.) More accurate knowledge of knee joint contact forces during high flexion activities may lead to safer high flexion implant designs, better understanding of wear mechanisms, and prevention of complications such as aseptic loosening (Komistek et al., 2005.) High flexion is essential for lifestyle and cultural activities in the developing world, as well as in Western cultures, including ground-level tasks and chores, prayer, leisure, and toileting (Hemmerich et al., 2006.) In vivo tibial loads have been reported while kneeling; but only while the subject was at rest in the kneeling position (Zhao et al., 2007), meaning that the loads were submaximal due to muscle relaxation and thigh-calf contact support. The objective of this study was to report the in vivo loads experienced during high flexion activities and to determine how closely the measured axial joint contact forces can be estimated using a simple, non-invasive model. It provides unique data to better interpret non-invasively determined joint-contact forces, as well as directly measured tiobiofemoral joint contact force data for two subjects.
Two subjects with instrumented tibial implants performed kneeling and deep knee bend activities. Two sets of trials were carried out for each activity. During the first set, an electromagnetic tracking system and two force plates were used to record lower limb kinematics and ground reaction forces under the foot and under the knee when it was on the ground. In the second set, three-dimensional joint contact forces were directly measured in vivo via instrumented tibial implants (Heinlein et al., 2007.) The measured axial joint contact forces were compared to estimates from a non-invasive joint contact force model (Smith et al., 2008.)
The maximum mean axial forces measured during the deep knee bend were 24.2 N/kg at 78.2° flexion (subject A) and 31.1 N/kg at 63.5° flexion (subject B) during the deep knee bend (Figure 1.) During the kneeling activity, the maximum mean axial force measured was 29.8 N/kg at 86.8° flexion (subject B.) While the general shapes of the model-estimated curves were similar to the directly measured curves, the axial joint contact force model underestimated the measured contact forces by 7.0 N/kg on average (Figure 2.) The most likely contributor to this underestimation is the lack of co-contraction in the model.
The study protocol was limited in that data could not be simultaneously collected due to electromagnetic interference between the motion tracking system and the inductively powered instrumented tibial component. Because skin-mounted markers were used, kinematics may be affected by skin motion artefacts. Despite these limitations, this study presents valuable information that will advance the development of high flexion total knee replacements. The study provides in vivo measurements and non-invasive estimates of joint contact forces during high flexion activities that can be used for joint simulator protocols and finite element modeling.
Introduction
Advanced medical imaging techniques have allowed the understanding of the patterns of relative bone motions at human joints1. However, poor imaging contrasts of soft tissues have not allowed the full understanding of various glenohumeral ligaments (GHL) functions during glenohumeral joint (GHJ) manoeuvres. This is presently a significant limitation to research as these structures are said to be responsible for the passive stability of the GHJ2. Furthermore, the repairs of GHJ instability often take recourse to these structures3. Earlier studies have presented a model that numerically reconstructs or simulates GHJ motions4 and how the locus of bony attachment points of the GHLs on a dynamic GHJ could be numerically tagged and trailed5. The aim of this study was to advance these previous findings by developing an algorithm that allows the quantification of GHL lengths at any instantaneous position of the GHJ.
Materials and Method
CT scan of a set of humerus and scapula was reconstructed into two individual surface meshes of interconnected nodes, each node having a unique vectorial identification in space. The two attachment nodes (
Bacterial infection related to prosthetic replacement is one of the serious types of complications. Recently, there has been a greater interest in antibacterial biomaterials. In order to reduce the incidence of replacement-associated infections, we developed a novel coating technology of Hydroxyapatite (HA) containing silver (Ag). We reported the Ag-HA coating showed high antibacterial activity against
Ag-HA or HA powder was sprayed onto the commercial pure titanium disks using a flame spraying system. The HA coating disks were used as negative control. The biofilm-forming methicillin sensitive
The number of the bacteria on these disks was not so different between Ag-HA and HA coating after rinsing. After biofilm-forming test, the coverage of the biofilm of BF-MSSA was 2.1% and 81.0% on the Ag-HA and HA coatings, respectively. Similarly, in the case of BF-MRSA, it was 7.7% and 72.0% on the Ag-HA and HA coatings, respectively. Though bacteria slightly adhered, biofilm was hardly observed on the Ag-HA coating. The biofilm on the HA coating was extensive and mature. The inhibition effect of biofilm formation on the Ag-HA coating might be ascribed to the antibacterial effect by Ag ions released from the coating. Because Ag ions have a broad spectrum of antibacterial activity against pathogens, including biofilm forming bacteria, they inhibited the biofilm formation on the Ag-HA coating by killing adherent bacteria. Even in a flow condition, it was suggested that the AgHA shows the antibacterial activity, though the conditions in this work are different from those in living body.
Fracture of the acetabulum can lead to degenerative arthritis of the hip, avascular necrosis of the femoral head, or both. Total hip arthroplasty is a common form of surgical treatment when significant joint changes and pain are present.
Ten patients with fracture acetabulum were treated in this study using metal on metal total hip arthoplasty. The initial fracture was posterior wall fracture in one patient, posterior column fracture in one patient, transverse fracture in 2 patients, fracture dislocation in 3 patients and fracture posterior wall and column in 3 patients. The indications of arthroplasty were secondry osteoarthritis after internal fixation or after conservative management or collapse of the femoral head. Arthroplasty was done after an average period of 1.8 years (range from 1 to 4 years).
After a follow up period ranged from 3 to 7 years with a mean of 4.6 years, the Harris hip score was improved from a mean of 51 (range 20 to 65) to a mean of 92.5 (range 90 to 95). Infection occurred in one case and two stages revision was done. Another case developed loosening of the acetabular component and was revised using cementless cup fixed with screws and bone graft.
Metal on metal THR after acetabular fracture are relatively uncomplicated and lead to a good outcome despite the difficulties faced during the procedure.
To review prospectively collected data on patients undergoing femoral revision arthroplasty for failed cemented or cementless primary stems.
Materials & Methods
All patients undergoing primary and revision joint replacement surgery at our institution are prospectively entered into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. These investigations are repeated 3 months, 6 months, 1 year and yearly thereafter at each patient visit.
This database identified all patients undergoing femoral revision arthroplasty over the last 10 years.
Results
There were a total of 231 patients with 248 revision procedures performed. There were 127 female and 104 male patients and the mean age at the time of revision surgery was 69.4 years. Twenty-two of these patients had had at least one prior revision operation on the index hip. Thirty hips were treated with a cemented Echelon stem and 218 treated with a cementless Echelon stem. Of the 248 hips 14 patients were lost to follow-up (14 hips) and 9 patients (9 hips) are deceased. The average follow-up was 5.9 years.
Of the 225 hips remaining in the follow-up series there was a single case of aseptic loosening confirmed radiologically. Twenty-one hips were diagnosed with infection (9.3%); 6 of those patients had had at least one prior revision procedure and 4 additional patients had a prior diagnosis of infection. Therefore, 10 of the 21 hips were either definitely or probably infected at the time of their revision operation on which we are reporting. Nine patients (4%) had multiple dislocations post-operatively. These were patients who had undergone multiple revisions or whose primary revision operation was for instability. An additional 18 patients (8%) had a single dislocation treated by closed reduction requiring no further treatment.
There were 6 hips with intra-operative fracture requiring immediate re-revision plus fracture fixation and a further 12 hips (5.3%) who sustained a peri-prosthetic fracture some time after their revision procedure.
Despite the number of complications the majority of patients required no further surgical treatment. Eleven hips (4.8%) required re-revision of the femoral component. Therefore the overall survival rate at 5.9 years of the Echelon revision stem was 95.2%.
Different femoral designs in TKA have shown multiple effects on the conformity of the patella-femoral joint. Historically, this anatomical relationship may interfere with clinical results. The objective of this study was to compare the reproducibility of a correct patello-femoral conformity in patients underwent TKA utilizing modern femoral implants.
MATERIALS AND METHODS
We performed 50 consecutives TKA in fifty patients affected by knee arthritis utilizing the PFC Sigma System (De Puy, Warsaw, USA) with a new femoral design, having a prolonged anterior flange and a “smoother” throclea. The surgical procedure was performed utilizing the Sigma HP instrumentation to allow 3 degrees of external rotation of the femoral component and the “balanced gaps technique” was chosen. All patellae were replaced. All patients were evaluated preoperatively and at six months follow-up both clinically with the Knee society Score as well as radiografically: standing 30x90 cm. view, Merchant view, standard lateral view and a CT-scan with two millimeters cuts (Berger Protocol) at 20 degrees of flexion were all done. Particular attention was paid to the following CT measurements: patellar tilt, patellar conformity angle, patellar lateralization, femoral component external-rotation in relation to the patellar sitting. Statistical analysis was performed utilizing the t-test e the Wilcoxon test (p<.05).
RESULTS
Any patient was dropped from the study group. Femoral component positioning in relationship to the trans-epicondilar axis showed at follow-up an external rotation of 2.74° (± 2.10°) respect to a preoperative value of 5.7 ° (± 1.80°). Average patellar conformity angle was at follow-up 12.5 (range, -2.5 ° - 28.2 °) respect to an average preoperative value of 10.3° (range, 1.5 – 25.6). Average patellar tilt at follow-up was 2.8°(±7.5°) respect to a preoperative average value of 18.5° (±8.5 °). Average lateralization index was at follow-up 2.7 mm (range, - 3.4 – 7.1 mm) respect to a preoperative value of 12.2 mm (± 4.8 mm).
Extensor mechanism disruption in total knee arthroplasty (TKA) occurs infrequently but often requires surgical intervention. We compared two cohorts undergoing extensor mechanism allograft reconstruction, one group had an extensor mechanism rupture, and the other had a recurrent ankylosed knee. Thirteen consecutive patients with extensor mechanism disruption or ankylosis after TKA were treated. Two different types of extensor mechanism allografts were used: quadriceps tendon-patella-patella tendon-tibial tubercle, and Achilles tendon allograft(Fig1). Demographic factors, diagnosis at extensor failure, Knee Society clinical rating scores, radiographs, and patient satisfaction were recorded. The average time from extensor mechanism disruption to surgery was 6.6 months (range, 1-24 months). At a mean followup of 24 months (range, 6-46 months), all patients were community ambulators. None of the patients showed a postoperative extensor lag. Average postoperative maximum flexion was 97° (90-115°) for the ruptured group and 80° (75-90) for the ankylosed grup. All patients thought their functional status had improved, and 87% were satisfied with the results of the allograft reconstruction (Fig 2, 3, 4, 5). One patient had allograft failure due to recurrent infection after re-revision for sepsis. The total extensor mechanism allograft and Achilles tendon allograft both were successful in the treatment of the failed extensor mechanism and showed promising results for the treatment of the ankylosed knee.
The aim of tissue sparing surgery in total knee arthroplasty is to reduce surgical invasivity to the entire knee joint. Surgical invasion should not be limited only toward soft tissues but also toward bone. The classic technique for total knee arthroplasty implies intramedullary canal invasion for proper femoral component positioning. This phase is associated to fat embolism, activation of coagulation, and occult bleeding from the reamed canal. The purpose of our study was to validate a new extramedullary device which relies on templated data.
Two-hundred patients in four different orthopaedics centres were randomized to undergo primary total knee arthroplasty either using standard intramedullary femoral instruments (IM group) or using a new extramedullary device (EM group). A new set of instruments was developed to control the sagittal and coranl plane of the distal femoral resection. The extramedullary instrument was calibrated referencing to templated data obtained from the preoperative long-limb radiograph (Fig 1, 2). Varus-valgus orientation of the resection were established by moving the two paddles according to templated data. An L-shaped sliding tool (5 centimetres long) over the anterior cortex controls the flexion-extension parameter of the resection and is intended to allow a cut flush with the anterior cortex at 0° of angulation with the distal aspect of the femoral diaphysis on the sagittal plane
Femoral component coronal alignment was within 0±3° of the mechanical axis in 86% of the IM group and 88% of the EM group. Sagittal alignment of the femoral component was 0±3° in 80% of the IM group and 94% of the EM group. There was no difference in the average operative time between the two groups. The EM group showed a trend toward less postoperative blood loss
Extramedullary reference with careful preoperative templating can be safely utilized during total knee arthroplasty.
The anterior curve of the tibial plateau cortex represents a realiable and reproducible landmark which may help aligning the tibial component with the femoral component and the extensor mechanism
Few studies analyzed the tibial component rotational alignment during total knee arthroplasty. Malrotation can affect both patello-femoral and tibio-femoral postoperative function. We evaluated the rotational relationship between femur and tibia, and we investigated which tibial landmark consistently matches the rotation of the femoral epicondylar axis in full extension (Fig 1).
Axial magnetic resonance images of 124 normal knees (statistical power 1-beta=0.8) were analyzed separately by three authors. Scanograms were obtained with the knee in full extension and with the long axis of the foot (second metatarsal bone) aligned on the neutral sagittal plane. The surgical epicondylar axis was drawn and projected over the proximal tibia and tibial tuberosity slices. Multiple anatomical tibial rotational landmarks were drawn and symmetric tibial component digital templates of different sizes were aligned according to each landmark. Alignment of the virtual tibial components was then compared to that of the projected femoral epicondylar axis (Fig 2). The best antero-posterior line to achieve rotational matching between the components was drawn on the proximal tibia slice of each patient.
Results of rotation (positive = external rotation, negative = internal) relative to the epicondylar axis were (Fig 3): (a) Medial third-to the middle third of the tibial tubercle 1.2°+/−5.7, (b) Akagi's line (centre of the posterior cruciate ligament tibial insertion to the most medial part of the tibial tubercle) -11.5+/−6.5, (c) The anterior curved tibial plateau cortex (curve-on-curve matching between the tibial template and the anterior cortex) 1.0+/−2.9. Intraclass correlation coefficient resulted 0.923, 0,881, and 0.949 for the Akagi's line, Middle third of tibial tubercle, and the curve-on-curve reference respectively.
The anterior curve of the tibial plateau cortex represents a realiable and reproducible landmark which may help aligning the tibial component with the femoral component and the extensor mechanism (Fig 4, 5).
Background
Revision THA presents significant challenges for the surgeon when the proximal femur is deficient or mechanically unreliable. The aim of this study is to assess the clinical and functional results of the use of tumor enndoprosthesis to reconstruct the proximal femur when there is massive bone loss.
Patients and Methods
A prospective study was conducted involving 10 cases. The follow up of the cases ranged from 12 months to 30 months with a mean period of an average of 23months. The indications for revision surgery were aseptic loosening in 9 cases and septic loosening in one case Harris hip score was used for pre and postoperative clinical evaluation of the patients
We present a new technique for TKA implantation which utilizes patient-specific femoral and tibial positioning guides developed from MRI to offer an individualized approach to total knee replacement.
This is a prospective non controlled study which aims to analyse the precision of this technique, its advantages and inconvenients in comparison with the conventional instrumented technique.
Material
The MRI provides a consistent three-dimensional data set of the patient's anatomy which allows for 3D axis identification.
The ideal position and sizing is performed by the surgeon on this 3D model and the patient specific guides are manufactured in advance in order to reproduce the bone cuts corresponding to this positioning and implant size. There are no intramedullary nor extramedullary instruments during the surgery.
Method
We compared 20 patients operated with this technique with 20 patients operated with the conventional technique.
The hypothesis was a difference < 2° between the 2 techniques
The measured parameters were:
HKS, HKA, tibial slope, femoral rotation on CT
Duration, bleeding, pain on VAS and morphine consumption, active flexion, KSS, Oxford score, recovery of independant walking and delay of return to home.
Both groups were identical for gender, age, BMI, etiology, comorbidities, pain and rehabilitation protocols.
Introduction
Hypothermia is the drop in body temperature under 35°C (95°F), It has implications in immunological function and healing process, increasing the infection and the cardiovascular risk. During hip arthroscopy patients are exposed to several risk factors that may lead to hypothermia.
Objective
to determinate if there are hypothermia and which are the factors contributing to hypothermia during hip arthroscopy.
The present clinico-radiographical study evaluated the long term performance of a Ti-Al-V alloy cementless modular press-fit cups (Fitek™) having, on the outer surface, an oriented multilayer titanium mesh (Sulmesh™) with 65% tridimensional porosity and 2 fins applied to the outer surface. Fins were initially designed for anti-rotatory purposes but showed to give an excellent initial mechanical stability. Thus, in the following years, we have designed 2 other cups having 8 fins and ceramic insert. In this paper we compare the design and the results obtained with these 3 cups.
We have reviewed the first 100 consecutive FITEK cups implanted in 92 patients with an average FU of 9,7 years (range 9-11 years). Results were evaluated with the Harris score. We had 86 Excellent, 10 Good, 2 Fair and 2 Poor. In this series we always used 28 mm heads.
Dysplastic patients showed inferior results compared to arthritics patients in different parameters, as pain, limp, ROM (p < 0.05), putting socks and shoes (p < 0.05).
Radiographically, our cups were implanted in a fairly horizontal position (36.5° an average).
At the last FU radiolucent lines were present in 14 % of the cases, never progressive.
In no case we found a change of position of the cup, and in this series no revision was necessary.
Between 2005 and 2008 we have implanted 140 consecutive Delta Fins cups with ceramic-on-ceramic articulation. The fins of this cup have a trapezoidal shape, with HA coating. The cup has an interference of 2 mm. The Delta ceramic insert allows the use of 32 or 36 mm heads.
Clinico-radiographical results were very good. One cup needed to be revised for aseptic loosening consecutive to a surgical error (undersizing)
The H.M.S. cup is made of Porous Titanium with 8 fins having a triangular section, in order to increase their penetration into cortical bone. The ceramic insert allows even larger ceramic insert (32, 36 and 40). Preliminary clinico-radiographical results were excellent, with complete initial mechanical stability and great ROM due to the large ceramic heads.
The presence of fins on the outer surface of cementless cups enhances primary stability and fixation and the use of large ceramic heads improves ROM and subjective patients satisfaction.
Purpose
Introduce an Integrated Approach for Orthopedic-Sports Medicine Practice and Patient Care Management that
Is built around effective and efficient surgical techniques, and patient care management processes
Integrates Operations and Service Excellence best practices with patient care management processes
Integrates orthopedic care delivery between outpatient clinic, pre-surgery, surgery, inpatient, (acute care) and post acute care settings
Delivers exceptional clinical, patient satisfaction and financial outcomes as validated by independent national healthcare benchmarking organization
Helps position Ortho-Sports medicine services for strategic growth
Is replicable to develop Ortho-Sports Medicine Centers of Excellence
Presentation illustrates the ‘Ten Elements’ approach to implement the Ortho-Sports Medicine Centers of Excellence and demonstrate the effectiveness of the approach with an outcomes study from over 1000 total knee arthroplasty (TKA) procedures. During the presentation, the speakers would share the key clinical, patient satisfaction, and financial outcomes achieved by the implementation of the best practices defined in our ‘Ten Elements’ approach. All performance data elements are collected, validated and analyzed by an independent third party, national healthcare benchmarking company.
During the presentation Dr. Bramlett would elaborate on the surgical protocol, and the key differentiating steps in procedure technique from traditional approach that significantly enhances procedure effectiveness, efficiency and lowers the patient complication rate as demonstrated by benchmarking data. Speakers would further present the key elements of Total Knee Arthoplasty procedure that focus on patient education, patient participation in pre-surgical weight loss and pre-habilitation program, anesthesia approach, avoiding tourniquet use and deep veen thrombosis (DVT) risk reduction, early post operative patient ambulation and weight bearing, and post operative patient management approach. On average the ortho-sports medicine clinical of Alabama TKA patients are disharged from the hospital in 2.6 days, and experience 65 percent less complications than expected for a similar patient population and assume early control of their independent functionality.
Wear of the polyethylene (PE) insert in total knee replacements can lead to wear-particle and fluid-pressure induced osteolysis. One major factor affecting the wear behaviour of the PE insert in-vivo is the surface characteristics of the articulating femoral components. Contemporary femoral components available in Canada are either made of cast Cobalt Chromium (CoCr) alloy or have an oxidized zirconium surface (Oxinium). The latter type of femoral components have shown to have increased abrasive wear resistance and increased surface wettability, thus leading to reduced PE wear in-vitro compared with conventional cast CoCr components. Although surface damage has been reported on femoral components in general, there have been no reports in the literature as to what extent the recommended operating techniques affect the surface tribology of either type of femoral component.
Twenty-two retrieved total knee replacements were identified with profound surface damage on the posterior aspect of the femoral condyles. The femoral components were of three different knee systems: five retrievals from the NexGen(r) total knee system (Zimmer Inc., Warsaw, IN), twelve retrievals from the Genesis II(r) total knee system (CoCr alloy or Oxinium; Smith & Nephew Inc., Memphis, TN), and five retrievals from the Duracon(r) total knee system (Stryker Inc., Mahwah, NJ). Reasons for revision were all non-wear-related and included aseptic loosening in two cases, painful flexion instability, and chronic infection. All retrieved femoral components showed evidence of surface damage on the condyles, at an average of 99° flexion (range, 43° – 135° flexion). Titanium (Ti) alloy transfer and abrasive surface damage were evident on all retrieved CoCr alloy femoral components that came in contact with Ti alloy tibial trays. Surface damage on the retrieved Oxinium femoral components was gouging, associated with the removal and cracking of the oxide and exposure of the zirconium alloy substrate material. CoCr alloy femoral components that had unintended contact with CoCr alloy tibial trays also showed evidence of gouging and abrasive wear.
All femoral components showed severe surface damage in the posterior aspect of the condyles. The femoral surface was heavily scratched and the oxidized zirconium coating surface appeared removed. The surface analysis suggested that the surface damage most likely occurred during the time of initial implantation. In particular, it appeared that the femoral condyles were resting on the posterior aspect of the tibial tray in flexion, thus scratching the femoral components. Such scratches could potentially lead to accelerated PE insert wear and reduced implant longevity, thus making expensive revisions surgery necessary. The authors strongly suggest a revision of the current operating techniques recommended by the implant manufacturer to prevent this type of surface damage from occurring.
The paper describes various surgical techniques and devices for: nucleus pulpous replacement and total lumbar disc arthroplasty/L TDR, as well as other dynamic-system preservation motion stabilization/fixation without fusion techniques (ISS-ILS, DF/semirigid (based on screw & rods)) vs. fusion.
Coverage includes indications and contraindications, surgical approaches, and the latest constructs and clinical trial results.
Introduction
Our clinic has started to use MAZOR's Spine-Assist(r) robotic device in routine spinal surgery practice since 2006. The use of this system is diverse and now applicable for Vertebroplasty, Biopsy procedures and different techniques of Spinal fusion. During this time our clinic performed near 150 robotic assisted surgeries. Amongst its benefits the system allows the reduction of the duration of fluoroscopic exposure in the OR, better accuracy due to computerized assisted planning and navigation, avoidance of human caused complications and a less traumatic procedure for the patient. On the other hand, the duration of the procedure is prolonged, the wound is subdued to a longer exposure in cases of the open surgery, and the operational cost is higher and requires a good trained medical staff.
Materials and Methods
In the last 2 years we have performed 56 robotic assisted Vertebroplasty procedures (research group). At the same time we have performed 44 non assisted Vertebroplasty procedures. There was a significant difference in the fluoroscopic time and subsequent exposure time to radiation between the groups: in the research group we used only an average of 3 seconds of staff fluoroscopic exposure (an average of 5 fluoroscopic images) compared to an average of 11 seconds of exposure (an average of 24 fluoroscopic images). Furthermore, we have successfully inserted more than 400 pedical screws with less than 1mm accuracy from planning, out which only 8 were misplaced. Subsequently we have also performed 16 biopsies, which were effective as CT based biopsies. The average duration of a surgical procedure without the use of the system in 1 level fusion was 82 min. With the use of the system the average time was 106 min. The operational cost with the use of the system was about 1,000 ∊ more expensive. Furthermore, the use of the system required performing of an additional CT scan with 1 mm slices, which caused an additional exposure to patient radiation.
Undisplaced or minimal displaced medial neck femoral fractures are treated with canulated screws either in young or in elderly patients with good functional capacity, without severe comorbidity and cognitive impairment. We also perform this procedure in patients with very low daily activities and affected by severe comorbidity, with the aim to reduce pain. We reserve total hip replacement in middle-advanced age, with good level of functional activity and adequate bone-stock. We use bipolar hemiarthroplasty in patients that need early mobilization for the presence of comorbidities that could worsen. We prefer cemented bipolar hemiarthroplasty, as it gives an optimal primary stability, without press-fit. We prefer to utilize bipolar hemiarthroplasty with memory shape stem F.G.L. (Fig.1) in high risk patients (ASA classification). In fact the use of cement prolongs duration of surgery and is associated with higher perioperative mortality from cardiopulmonary complications. This stem in its metaphyseal region has 10 tabs, made of a Nitinol alloy (Ni-Ti). The feature of this alloy is to enlarge when brought to a certain temperature. When F.G.L. stem is mantained at 4° - 7° C the Nitinol (r) tabs are in the “restrained” configuration. Just at the time of surgery procedure, the stem is taken out of the refrigerator and inserted into the femoral diaphysis. At corporeal temperature, the Nitinol tabs enlarge, compressing the metaphyseal cancellous femoral region and give an immediate primary stability. We report clinical and radiological results of 15 patients (mean follow-up: 8 months) that underwent surgical procedure of bipolar hemiarthroplasty with F.G.L. stem in our department from March 2008 to December 2009. We had no perioperative complications and the results overlapped those of patients that underwent standard cemented bipolar hemiarthroplasty. The advantage of the use of F.G.L. stem is that it allows an immediate primary stability without searching an extreme press-fit. The disadvantage is the higher cost respect a standard cemented bipolar hemiarthroplasty. Therefore its use should be limited to those patients in which the surgery time must be contained for severe comorbidity, or in patients in which specific cardio-pulmonary complaints make dangerous the use of cement.
Background
The increasing desire to protect the periarticular structures led the need of a Tissue Sparing Surgery. The accesses most widely used are the direct-lateral approach and the postero-lateral one, both with patient in lateral decubitus. Aim: This accesses require however an incision of tendons and muscles even in their minimally invasive technique, so we looked for an approach that would wholly protect the periarticular structures and allow us not to revise our experience in patient positioning, preparation of the operating field and surgeon's position during surgery. Our intent was to leave the acquired knowledge unchanged and to preserve unaltered the anatomical landmarks that we had previously identified and consolidated for the correct positioning of the components.
Methods
We have used this approach in more than 180 cases of primary hip arthroplasty. Clinical control includes: Oxford Hip Score, VAS and X-Ray.
Co-Cr-Mo alloys are widely used for biomedical implant materials such as artificial hip and knee joints owing to their excellent corrosion and wear resistance as well as higher strengthening properties. However, the alloys exhibits sever brittle nature under an as-cast condition. It is generally recognized that refinement of the grain size of the metallic materials by means of hot-forging processes is an effective methodology to strengthen the alloy. Dynamic recrystallization (DRX) is an effective metallurgical process for grain refinement during hot deformation. However, there are few studies on the hot deformation behavior of Co-Cr-Mo alloy, especially grain refinement through DRX. In the present study, DRX and grain refinement during hot deformation of Co-29Cr-6Mo alloy has been investigated under various conditions such as deformation temperature and strain rate.
Although at strain of 5% hot deformed microstructure maintains the original grains, the grain size decreases with increasing the strain and exhibits the average grain size of approximately 2μm at strain of 60%. Ultra fine grained microstructure with the grain size of approximately 0.5 μm was obtained under deformation at a 1323 K at a strain rate of 0.1s-1. The original grains are broken up into different grains due to the new boundary formation not only near the initial boundaries but also in the interior of the grains at large strain. This grain fragmentation without bulging in the course of hot deformation is associated with considerably low stacking fault energy (SFE) of the Co-29Cr-6Mo alloy even at the deformation temperatures.
Purpose
To evaluate the clinical and radiologic midterm results of rotational acetabular osteotomy (RAO) in incongruent hip joints.
Material and Methods
A consecutive series of 15 hips in 14 patients who underwent RAO in incongruent hip joint were evaluated at an average follow-up of 52.3 months (range from 36 to 101 months). The average age at operation was 27 years (range from 12 to 38 years) old. The preoperative diagnoses were developmental dysplasia in 4 hips, sequelae of Legg-Calvé-Perthes disease in 8 hips, and multiple epiphyseal dysplasia in 3 hips. The RAO procedures were combined with a femoral valgus oseotomy in 10 hips, advance osteotomy of greater trochanter in 4 hips, derotational osteotomy in 2 hips. Clinically, Harris hip score, range of motion, leg length discrepancy(LLD) and hip joint pain were evaluated. Radiological changes of anterior and lateral center-edge(CE) angle, acetabular roof angle, acetabular head index(AHI), ratio of body weight moment arm to abductor moment arm, and a progression of osteoarthritis were analyzed.
Purpose
The ultimate goal in total hip arthroplasty is not only to relieve the pain but also to restore original hip joint biomechanics. The average femoral neck-shaft angle(FNSA) in Korean tend to have more varus pattern. Since most of conventional femoral stems have relatively high, single, fixed neck shaft angle, it's not easy to restore vertical and horizontal offset exactly especially in Korean people. This study demonstrates the advantages of dual offset(especially high-offset) stem for restoring original biomechanics of hip joint during the total hip arthroplasty in Korean.
Materials and Methods
180 hips of 155 patients who underwent total hip arthroplasty using one of the standard(132°) or extended(127°) offset Accolade cementless stems were evaluated retrospectively. Offset of stem was chosen according to the patient's own FNSA in preoperative templating. In a morphometric study, neck-shaft angle of proximal femur, vertical offset and horizontal offset, abductor moment arm were measured on preoperative and postoperative both hip AP radiographs and the differences and correlation of each parameters, between operated hip and original non-operated hip which had no deformity (preoperative ipsilateral or postoperative contralateral hip), were analyzed.
CLS Spotorno expansion acetabular cup is in use since 1984 for uncemented Metal-Polyethylene (PE) total hip arthroplasties (THA). Metal-PE articulations are notoriously known to wear and lead to failure of THA. However, catastrophic breakage of expansion acetabular cup is rare. Our 74-year-old male who was diagnosed with bilateral osteonecrosis of femoral head, underwent bilateral THA using CLS Spotorno metal expansion acetabular cups (Protek, AG, Bern) in 1991. He had irregular follow-up since then. In 2005, he presented with right hip pain and inability to walk without support. Anteroposterior (AP) hip radiographs established the diagnosis of catastrophic failure of right THA secondary to severe liner wear and acetabular osteolysis. Patient chose to postpone the revision surgery and opted for wheel chair ambulation. He presented 4 years later, when the right hip pain became unbearable. Anteroposterior as well as lateral hip radiographs showed worsening of cup breakage with superolateral migration of metal femoral head. Pelvic CT scans confirmed severe acetabular osteolysis in DeLee and Charnley's Zone 1, 2 & 3 with secondary loss of bony support to the expansion cup [Fig. 1]. A revision THA was strongly advised. However, patient sought for a pain-free rather than a fully ambulatory right hip and decided against a second THA. We performed resection arthroplasty of right hip with bone cement loading, respecting patient's decision. Intra-operatively, the metal femoral head was lying in the huge osteolytic defect in the roof of acetabulum. The 3 cranial wings of metal expansion shell were broken with corresponding wear of the cranial pole of polyethylene liner [Fig. 2]. We were able to gratify patient's expectations and patient is able to ambulate with the aid of one crutch at latest follow-up. However, it is clearly evident that a timely and regular follow-up would have identified the initial PE wear and secondary osteolysis. Additionally, it can avoid extensive procedures like a revision THA or resection arthroplasty by allowing simple procedures like modular PE liner and the femoral head exchange. A comprehensive review of literature for catastrophic acetabular component breakage revealed 10 such cases, although with different cup designs. To the best of our knowledge, this is the first case of CLS expansion cup breakage for metal-PE articulation. Majority of these cases have a presence of extensive liner wear and pelvic osteolysis along with a post-operative irregular follow up. This case stresses on importance of regular follow-up even after many years of index THA to identify early PE wear and prevent secondary catastrophic complications.
Introduction
Alumina Ceramic liners are increasingly used in patients undergoing Total Hip Replacement (THR). The rate of fracture of ceramic liner is decreasing with improved manufacturing techniques from 1st to 3rd generation alumina-ceramic liners. We report the first case of a fracture of a modern, 4th generation alumina bearing ceramic liner, which incorporates a metal sheath to help avoid fracture. Our case is a 60 years old female presenting two years and three months after a bilateral total hip replacement using Stryker Trident cup, securfit stem and alumina on alumina bearing ceramic liner. Ceramic liners are commonly used, especially in young patients because of their excellent biocompatibility, low wear rate and superior tribology. Although fracture of ceramic liner is a less common complication of modern total hip arthroplasty, it is a major concern with the use of ceramic on ceramic THR, the reason being brittleness of ceramic. Cases of 3rd generation ceramic liner fracture have been reported which might be associated with impingement due to excessive anteversion of the socket in Asian patients who habitually squat. Habitual squatting, sitting cross legged and kneeling were not characteristic of this case.
Methods
The patient presented with complains of mechanical grinding in left hip. She also reported a past history of clicking sound from left hip on extension of left hip and long stride gait. There was no history of trauma or fall. On examination she had a nonantalgic gait and left hip had audible and palpable crepitations. The range of motion on left hip was intact with no subluxation. Right hip was symptom free and examination did not detect any abnormalities.
Introduction
Modular tapered implants have been suggested as the optimal treatment in patients with severe femoral bone loss undergoing revision total hip arthroplasty (THA). The purpose of this study is to describe minimum 2 year follow up of patients treated with modular tapered prostheses for Paprosky type IIIB and IV femoral bone loss in revision THA.
Methods
44 Consecutive patients with Paprosky type IIIB (23) or IV (21) femurs undergoing revision total hip arthroplasty to cementless modular tapered prostheses were studied. Harris Hip Scores were obtained prior to revision on all patients except those presenting with acute implant failure or periprosthetic fracture. 10 Patients were deceased within 2 years of surgery; the remaining 18 were followed for an average of 42 months (range 25-69 months). Clinical outcomes were measured using the Harris Hip Score, and radiographs were assessed for signs of stem loosening or subsidence >4mm.
Introduction
When using press-fit stems in revision total knee arthroplasty (TKA), diaphyseal engagement optimizes stability. Attempts to maximize press fit may lead to periprosthetic fracture; however, the literature offers no guidance regarding the prevalence or management of this complication. The purpose of this study is to report the incidence, risk factors, and outcomes of these fractures.
Methods
634 Stemmed implants (307 femoral and 327 tibial) from 413 consecutive revision TKAs were reviewed. Immediate and 6 week post-operative radiographs were examined. Patient age, gender, stem length, diameter, and offset were evaluated as potential risk factors for fracture occurrence using a paired t-test for continuous and a chi-square analysis for categorical variables.
Introduction
Serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and synovial fluid white blood cell (WBC) count and differential are effective in diagnosing periprosthetic joint infection (PPJI); however their utility in patients with inflammatory arthritis is unknown. The purpose of this study is to determine the utility of these tests in patients with inflammatory arthritis.
Methods
934 Consecutive revision hip and knee arthroplasties were prospectively evaluated for PPJI. 202 Cases were excluded due to acute post-operative or hematogenous infection. 690 Patients had non-inflammatory and 42 had inflammatory arthritis. Receiver operating characteristic (ROC) curves were used to establish optimal ESR, CRP, WBC, and % neutrophil values for diagnosis of PPJI, and the area under the curve (AUC) was calculated to determine the overall accuracy.
Introduction
Clinical outcomes of UKA procedures are sensitive to malalignment of the components, and thus show significant variability in the literature. A new robotic procedure addresses isolated medial compartment osteoarthritis with the classic indications of UKA. Using precision planning through patient specific 3D modeling and reconstruction, a robotic arm gives the surgeon control of resurfacing the knee joint, allowing for consistent precision according to the previously chosen plan. Through the precise preparation of bone surfaces and inter-component alignment, this procedure is designed to significantly increase accuracy and decrease mal-alignment, thus increasing post-operative physical and function outcomes. This paper evaluates four year clinical outcomes of this novel surgical procedure.
Methods
The first seventy-three (42 male, 31 female) patients (average age: 71 ±10yrs) to receive a robotically assisted UKA enrolled in an IRB approved outcomes registry. Eleven patients were four years post operative and sixty-two patients were three years post operative at the time of the study. The average follow ups were 45 months and 35 months, respectively (range: 30 to 47 months). The tibial component for all patients was an all-poly inlay design.
Two-stage revision is the gold standard in treatment of TKA infection. Several risk factor as the type of microbical flora, presence of general and local comorbidity and the type of therapeutic protocol may influence the success rate of treatment. The aim of our study is to assess the impact of these factor on prognosis in two-stage revision in chronic periprosthetic knee infection. We treated 38 knees in 37 patients, with an overall recurrence of 23,5% (9 recurrences). Our series analisys shows that associated diseases can affect the final result, with recurrence of infection in 12% of patients with one risk factor and in 33% of patients with association of comorbidity, wherass any infection occurred if less than three comorbidity were present. We also detect a statistically significative higher rate of recurrence in presence of local risk factor and in infection sustained by methicillin-resistant germs or with poly-microbial flora. Presence of these factors significantly affect prognosis and should be taken into serious consideration in the decision process leading to appropriate treatment.
Blood loss during the perioperative period of total joint arthroplasty has been well described in the literature. Despite numerous advances, allogeneic transfusion rates are still reported as high as 50%. Often the literature focuses on one area or mechanism of blood loss prevention but this article focuses on a multimodal approach to blood loss prevention including preoperative optimization, intraoperative technique, and postoperative management. Hemoglobin drop and transfusion rates were retrospectively reviewed for 134 control patients undergoing total knee arthroplasty (TKA) in three groups. Group 1 included low risk patients (Hb >14 g/dl), Group 2 included intermediate risk patients (Hb 13-14 g/dl) utilizing reinfusion drain and preoperative autologous blood donation, and Group 3 included high risk (Hgb <13) patients treated with preoperative erythropoietin (EPO). These controls were then compared to two groups of patients undergoing minimally invasive total knee arthroplasty (MIS TKA). Group 4 included 20 consecutive patients undergoing MIS TKA with intraoperative injection of lidocaine and epinephrine along the arthrotomy site. Group 5 included 22 consecutive patients treated with similar technique plus the additional intraoperative use of a bipolar sealer device. The combined utilization of MIS TKA, epinephrine, and bipolar sealer minimized hemoglobin drop (2.74 (Std Dev 0.77) vs 3.29 (SD 1.05) g/dl, p= 0.01) and total blood transfusions (0.05 (SD 0.21) vs 0.86 (SD 0.63) units, p< 0.01) compared with the traditional TKA approach for high risk patients using reinfusion drain and preoperative autologous donation (Group 2). This series demonstrates how a busy knee practice minimizes hemoglobin drop and transfusion requirements with preoperative optimization of high risk patients utilizing EPO, minimally invasive technique, intraoperative hemostasis obtained with epinephering injection, use of a bipolar sealer, and postoperative management with a reinfusion drain.
Introduction
The purpose of this study was to determine the efficacy of a Multi-modal Blood Conservation protocol that involves pre–operative autologous blood donations (2 units) in conjunction with Erythropoietin supplementation as well as intra-operative conservation modalities.
Methods
A retrospective review of 104 patients with simultaneous bilateral total knee arthroplasty done between 2006-2009 was performed. Patients donated two units of blood, 4 weeks prior to surgery and also received Erythropoetin injections (40 k units 3weeks,2 weeks and 1 week prior to surgery). Intra- operative Blood Management included symptom-based transfusions, blood salvage devices, local epinephrine injections and fibrin spray. Pre-donation blood levels, peri-operative hemoglobin and hematocrit levels along with transfusion records were assessed.
Introduction
The anatomic abnormalities associated with the dysplastic hip increase the complexity of hip arthroplasty, in addition previous femural osteotomy can deformate proximal femur. Despite the fact that uncemented cup and stems are specifically designed for dysplasia to recover the true acetabular region in Crowe IV and sometimes Crowe III additional surgical procedure are required. Purpose of the study is to verify surgical procedures and explore reconstruction options on severe hip dysplasia.
Materials and methods
In last 25 years, 2308 arthroplasties were performed in dysplastic hips (565 cases had a previous femoral osteotomy). In 128 cases was required a correction of femoral side deformity: in 64 cases was performed a greater trochanter osteotomy (in 12 of these a proximal femoral shortening was associated), 55 cases were treated by a shortening subtrochanteric osteotomy (that allows corrections in any plane) and in 9 cases was performed a distal femur osteotomy.
Introduction
Aligning the tibial tray is a critical step in total knee arthroplasty (TKA). Malalignment, (especially in varus) has been associated with failure and revision surgery. While the link between varus malalignment and failure has been attributed to increased medial compartmental loading and generation of shear stress, quantitative biomechanical evidence to directly support this mechanism is incomplete. We therefore constructed and validated a finite element model of knee arthroplasty to test the hypothesis that varus malalignment of the tibial tray would increase the risk of tray subsidence.
Methods
Background
While in vivo kinematics and forces in the knee have been studied extensively, these are typically measured during controlled activities conducted in an artificial laboratory environment and often do not reflect the natural day-to-day activities of typical patients. We have developed a novel algorithm that together with our electronic tibial component provide unsupervised simultaneous dynamic 3-D kinematics and forces in patients.
Methods
An inverse finite element approach was used to compute knee kinematics from in vivo measured knee forces. In vitro pilot testing indicated that the accuracy of the algorithm was acceptable for all degrees of freedom except knee flexion angle. We therefore mounted an electrogoniometer on a knee sleeve to monitor knee flexion while simultaneously recording knee forces. A finite element model was constructed for each subject. The femur was flexed using the measured knee flexion angle and brought into contact with the fixed tibial insert using the three-component contact force vector applied as boundary conditions to the femoral component, which was free to translate in all directions. The relative femorotibial adduction-abduction and axial rotation were varied using an optimization program (iSIGHT, Simulia, Providence, RI) to minimize the difference between the resultant moments output by the model and the experimentally measured moments. Maximum absolute error was less than 1 mm in anteroposterior and mediolateral translation and was 1.2° for axial rotation and varus-valgus angulation. This accuracy is comparable to that reported for fluoroscopically measured kinematics. We miniaturized the external hardware and developed a wearable data acquisition system to monitor knee forces and kinematics outside the laboratory.
INTRODUCTION
Knee contact force during activities after total knee arthroplasty (TKA) is very important, since it directly affects component wear and implant loosening. While several computational models have predicted knee contact force, the reports vary widely based on the type of modeling approach and the assumptions made in the model. The knee is a complex joint, with three compartments of which stability is governed primarily by soft tissues. Multiple muscles control knee motion with antagonistic co-contraction and redundant actions, which adds to the difficulty of accurate dynamic modeling. For accurate clinically relevant predictions a subject-specific approach is necessary to account for inter-patient variability.
METHODS
Data were collected from 3 patients who received custom TKA tibial prostheses instrumented with force transducers and a telemetry system. Knee contact forces were measured during squatting, which was performed up to a knee flexion angle that was possible without discomfort (range, 80–120°). Skin marker-based video motion analysis was used to record knee kinematics. Preoperative CT scans were reconstructed to extract tibiofemoral bone geometry using MIMICS (Materialise, Belgium). Subject-specific musculoskeletal models of dynamic squatting were generated in a commercial software program (LifeMOD, LifeModeler, USA). Contact was modeled between tibiofemoral and patellofemoral articular surfaces and between the quadriceps and trochlear groove to simulate tendon wrapping. Knee ligaments were modeled with nonlinear springs: the attachments of these ligaments were adjusted to subject-specific anatomic landmarks and material properties were assigned from published reports.
Background
One of the main concern about reverse shoulder arthoplasty for the treatment of rotator cuff deficiency is scapular notching that is still an unsolved issue for this particular prosthesis. The purpose of this multicentric retrospective study is to compare two different concept of reverse prosthesis, one with a concentric glenoshere and the other one with a new eccentric glenoshere design that aim to minimize scapular notching.
Methods
From 2004 to 2009 67 patients were treated with a SMR reverse shoulder prosthesis (LIMA) with either concentric (figure 2) or eccentric glenosphere (figure 1). We selected for the study patients with criteria as much homogeneous as possible by the age and pathology. We then included for the study 25 patients (Group 1) with a concentric glenosphere and 21 (Group 2) with a eccentric glenosphere. All baseplates of concentric glenospheres were implanted with the most inferior aspect of baseplate that matched with the inferior glenoid ream, so that the glenosphere extended 4 mm beyond the glenoid inferiorly in order to minimize scapular notching. Every patient were followed clinically (Constant and Murley Score [C.S.] and Simple Shuolder test [S.S.T.]) and radiographically (notching, loosening and mechanical failure) with a minimum follow-up of 24 months. We also evaluated at the final follow-up psna (prosthesis-scapular neck angle), pgrd (peg glenoid rim distance) and DBSNG (distance between scapular neck and glenosfere).
In general TKA can be divided into two distinct groups: cruciate retaining and cruciate substituting. The cam and post of the latter system is in fact a mechanical substitution of the intricate posterior cruciate ligament. In our previous work we and many other investigators have focused on the movement of the femoral component relative to the tibial tray. Little information is available about the relative movement between the cam part of the femoral component and the post of the tibial insert. In this study we determine the distance and the changes in distance between the cam of the femoral component and the tibial post during extension, flexion at 90° and full flexion. The secondary purpose is to analyse possible differences between FBPS and MBPS TKA.
Methods
12 subjects' knees were imaged using fluoroscopy from extension over 90° to maximum kneeling flexion. The images were digitized. The 3-dimensional (3D) position and orientation of the implant components were determined using model-based shape-matching techniques, manual matching, and image-space optimization routines. The implant surface model was projected onto the geometry-corrected image, and its 3D pose was iteratively adjusted to match its silhouette with the silhouette of the subject's TKA components. The results of this shapematching process have standard errors of approximately 0.5° to 1.0° for rotations and 0.5 mm to 1.0 mm for translations in the sagittal plane. Joint kinematics were determined from the 3D pose of each TKA component using the 3-1-2 Cardan angle convention. This process resulted in a distance map of the femoral and tibial surfaces, from which the minimum separations were determined for the purpose of this study between cam and post (fig1.).
Separation distances between the tibial polyethylene (PE) insert's post and the femoral prosthesis component have been calculated in three steps. First, the surface models of all three components as well as their position and orientation were extracted from the data files produced by the fluoroscopic kinematic analysis. Next, a set of 12 points were located on the post of each tibial insert (fig2.). Finally, for each point, the distance to the femoral component was quantified. For each step in this process, custom MATLAB(r) (The MathWorks(tm) Inc., Natick, MA, USA) programs were used.
For each of the 12 points on the post, a line was constructed through the point and parallel to the outward-facing local surface normal of the post. The resulting set of lines was then intersected with the femoral component model. Intersection points where lines ran “out of” the femoral component, detected by a positive dot product of the femoral component surface normal with the post surface normal (used to define the line), were discarded.
Finally, the distances between the 12 points on the post and the intersection points on each line were calculated. For each line, the smallest distance was retained as a measure of the separation between insert and femoral component. Where a line did not intersect the femoral component, the corresponding separation distance was set to infinity.
In each position, distances are measured at 6 pairs of points. Two indices of asymmetry are analysed:
The absolute difference between both measurements within a pair. Perfect symmetry is present when this absolute difference equals zero. The proportion of pairs where one of both measurements equals infinity. Indeed, this situation refers to the presence of ‘extreme’ asymmetry.
A linear model for repeated measures is used to analyse the absolute differences as a function of the between-subjects factor condition (mobile bearing or fixed bearing) and the within-subject factors position (4 levels) and pair (6 levels). More specifically, a direct likelihood approach is adopted using a compound symmetric covariance matrix.
Results
There is a significant difference in absolute difference between the fixed and mobile bearing condition (p=0.046). On average, the absolute difference is higher in the fixed bearing condition, 1.75 (95%CI: 1.39;2.11) vs 1.20 (95%CI:0.78;1.62). (fig2.).
The number of joint revision surgeries is rising, and the complexity of the cases is increasing. In 58% of the revision cases, the acetabular component has to be revised. For these indications, literature decision schemes [Paprosky 2005] point at custom pre-shaped implants. Any standard device would prove either unfeasible during surgery or inadequate in the short term. Studies show that custom-made triflanged implants can be a durable solution with good clinical results. However, the number of cases reported is few confirming that the device is not in widespread use.
Case Report
A patient, female 50 yrs old, diagnosed having a pseudotumor after Resurfacing Arthroplasty for osteo-arthritis of the left hip joint. The revision also failed after 1 y and she developed a pelvic discontinuity. X-ray and Ct scans were taken and sent to a specialized implant manufacturer [Mobelife, Leuven, Belgium]. The novel process of patient-specific implant design comprises three highly automated steps.
In the first step, advanced 3D image processing presented the bony structures and implant components. Analysis showed that anterior column was missing, while the posterior column was degraded and fractured. The acetabular defect was diagnosed being Paprosky 3B. The former acetabular component migrated in posterolateral direction resulting in luxation of the joint. The reconstruction proposal showed the missing bone stock and anatomical joint location.
In the second step, a triflanged custom acetabular metal backing implant was proposed. The bone defect (35ml) is filled with a patient-specific porous structure which is rigidly connected to a solid patient-specific plate. The proposed implant shape is determined taking into account surgical window and surrounding soft tissues. Cup orientation is anatomically analyzed for inclination and anteversion. A cemented liner fixation was preferred (Biomet Advantage 48mm). Screw positions and lengths are pre-operatively planned depending on bone quality, and transferred into surgery using jig guiding technology (Materialise NV, Leuven, Belgium).
In the third step, the implant design was evaluated in a fully patient-specific manner in dedicated engineering (FEA) software. Using the novel automated CT-based methodology, patient-specific bone quality and thickness, as well as individualised muscle attachments and muscle and joint forces were included in the evaluation.
Implants and jig were produced with Additive Manufacturing techniques under ISO 13485 certification, using respectively Selective Laser Melting (SLM) techniques [Kruth 2005] in medical grade Ti6Al4V material, and the Selective Laser Sintering technique using medical grade epoxy monomer. The parts were cleaned ultrasonically, and quality control was performed by optical scanning [Atos2 scanning device, GOM Intl. AG, Wilden, Switzerland]. Sterilization is performed in the hospital.
CONCLUSION
A unique combination of advanced 3D planning, patient-specific designed and evaluated implants and drill guides is presented. This paper illustrates, by means of a clinical case, the novel tools and devices that are able to turn reconstruction of complex acetabular deficiencies into a reliable procedure.
Introduction
Fixation remains a challenge in Revision TKR. Irregular and cavitary bone loss may precludeproper metaphyseal cementation and pressurization. Metaphyseal sleeves have been proposed to improve theinherent rotational stability of the implant bone interface. The goal of this study was to assess the effect of the use of metaphyseal sleeves on the quality of the cement fixation achieved.
Methods
Fifty consecutive revision TKRs for AORI type 2 and 3 bone loss between January 2005 through January 2008 with average 2 years follow up were assessed retrospectively. Twelve patients were excluded for inadequate follow up. Nineteen patients with 26 cemented metaphyseal sleeves (15 tibiae and 11 femora) formed group 1 and 19 patients with 36 revision components (without metaphyseal sleeves) served as control (group 2). Patients were assessed clinically with knee society scores (KSS) and radiographically by quality of metaphyseal cement mantle and radiolucent lines(RLL). Groups were matched for pre-op bone loss and length of follow-up.
Introduction
Mechanical integrity of patella can be weakened by the technique of removing the articulating surface. The senior author developed the technique of maintaining subchondral bone of the lateral patellar facet in early 1980s. Though laboratory studies have demonstrated deleterious effect of excessive resection of patella on the strains in the remaining bone under load; clinical studies have not shown the importance of strong subchondral bone of lateral facet to have an effect on patellar fracture prevalence. We present the results of our patellar resection technique preserving the subchondral bone of lateral facet.
Methods
393 TKRs were performed between 1989 and 1996 using cruciate substituting modular knee with recessed femoral trochlear groove and congruent patello-femoral articulation. 45 patients with 48 knees died and 37 patients with 41 knees were lost to follow-up. Three hundred and four knees were followed for an average 10 years (range 5 -16 years). Patellar surface was resected with an oscillating saw without the use of cutting guide. The medial facet and most of the articular cartilage of the lateral facet was resected, while preserving the subchondral bone of lateral facet. An all-polyethylene implant with single peg was used in most cases.
Patients with osteochondrodysplasia frequently require Total Hip Arthroplasty at a younger age, as a result of early degenerative disease of the hip joint. The outcome of Modular Total Hip Arthroplasty in this group of patients has been reported previously. In this retrospective study we evaluated the outcome of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia.
Between 1974 and 2009, twenty one CADCAM Total Hip Arthroplasty procedures were performed in fourteen patients in our institution. There were eight female and six male patients, with the mean age at time of surgery of 40.95 years (20 to 78). The patients were followed up clinically and with the Harris hip score for a mean of 7.12 years (0.5 to 17 years).
Four of the twenty-one hips (23.8%) required revision surgery at a mean of 11.54 years (6.5 to 17 years); one required it for aseptic loosening of the femoral component; one required complete revision of the acetabular component; one required exchange of acetabular liner; and one was for symptomatic non-union of a lesser trochanter avulsion.
This study shows encouraging clinical outcomes of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia,
Purpose
The rate of arthroplasty or osteotomy in patients who had undergone autologous chondrocyte implantation (ACI) for osteochondral defects in the knee was determined. Furthermore, we investigated whether any radiographic evidence of osteoarthritis (OA) prior to ACI was associated with poorer outcome following surgery.
Methods
We retrospectively reviewed the medical notes and radiographs of 236 patients (mean age 34.9) who underwent ACI from 1998 to 2005 at our institution. Knee function was assessed according to the Modified Cincinnati Score (MCS) pre-operatively and at a mean of 64.3 months postoperatively (range 12 – 130). Radiographic changes were graded according to the Stanmore grading system.
The aim of this study is to investigate whether Metal-on-Metal (MoM) implants result in more chromosome aberrations and increased blood metal ions post-operatively when compared to Metal-on-Polyethylene (MoP) implants. Metal-on-metal arthroplasties are being inserted in increasing numbers of younger patients due to the increased durability and reduced requirement for revision in these implants. Recent studies have raised many concerns over possible genotoxicity of MoM implants. This is a prospective study of patients who have undergone elective total hip replacement, they were selected and then randomised into two groups. Group A received a MoP implant and group B received a MoM implant. Patients are reviewed pre-operatively (control group), at 3 months, 6 months, 1 year and 2 years post-operatively. On each occasion blood tests are taken to quantify metal ion levels (chromium, cobalt, titanium, nickel and vanadium) using HR-ICPMS method and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hybridisation (FISH). 53 patients have been recruited to date. 24 of whom had MoP prosthesis and 29 a MoM. 37 of these have had their one year follow-up with blood analysis and 14 have had 2 year follow up. Cobalt and chromium concentration increased during the first 6 months in both MoM and MoP groups, in the MoM group the chromium levels were twice that of MoP group and 12x that of the preoperative samples. Chromosome aberrations occurred in both groups. At 6 months both the MoM and MoP groups showed increase frequency of aneuploidy aberrations with further increases after one year. Structural damage in the form of translocations occurred in the MoM group after one year, but not in the MoP group, by two years there was a profound increase in translocations Preliminary results of this study show that the levels of chromium and cobalt are significantly higher in the MoM group compared to the MoP group. This corresponds to increases in chromosome aberrations in the groups with increases in structural chromosome damage after two years.
INTRODUCTION
Computer-aided systems have been developed recently in order to improve the precision of implantation of a total knee replacement (TKR). Several authors demonstrated that the accuracy of implantation of TKR was higher with the help of a navigation system in comparison to the conventional, manual technique. Theoretically, the clinical results and the survival rates should be improved. Our team was one of the first all over the world which decided to use routinely a navigation system for TKR.
Prostheses designed with a mobile bearing polyethylene component allow an increased congruence between femoral and tibial gliding surface, and should decrease the risk of long-term polyethylene wear. We designed a prosthetic system with one of the highest congruence on the current market. These prostheses might be technically more demanding than more conventional designs, and involve specific complications like bearing luxation. Navigation systems might be helpful in this was as well.
In the present study, we wanted to test clinically the theoretic advantages of these three specific points of our system (navigated implantation, mobile bearing and increased congruence) with a five-year clinical and radiological follow-up.
MATERIAL AND METHODS
128 patients were operated on at our Department with this TKR system between 2000, and were contacted for a five-year clinical and radiological follow-up. The clinical and functional results were evaluated according to the Knee Society Scoring System (KSS). The subjective results were analyzed with the Oxford Knee Score. The accuracy of implantation was assessed on post-operative long leg antero-posterior and lateral X-rays. The survival rate after 5 years was calculated according to the Kaplan-Meier technique.
INTRODUCTION
Computer-aided systems have been developed recently in order to improve the precision of implantation of a total knee replacement (TKR). Several authors demonstrated that the accuracy of implantation of an unicompartmental knee replacement (UKR) was also improved.
Minimal invasive techniques have been developed to decrease the surgical trauma related to the prosthesis implantation. The benefits of minimal-incision surgery might include less surgical dissection, less blood loss and pain, an earlier return to function, a smaller scar, and subsequently lower costs. However, there might be a concern about the potential of minimal invasive techniques for a loss of accuracy. Navigation might help to compensate for these difficulties.
Mobile bearing prostheses have been developed to decrease the risk of polyethylene wear. The benefits might be a better survival and less bone loss during revisions. However, these prosthesis are technically more demanding, and involve the specific risk of bearing luxation. Again, navigation might help to compensate for these difficulties.
MATERIAL AND METHODS
We wanted to combine the theoretical advantages of the three different techniques by developing a navigated, minimal invasive, mobile bearing unicompartmental knee prosthesis. 160 patients have been operated on at our institution with this system. The 81 patients with more than 2 year follow-up have been re-examined. Complications have been recorded. The clinical results have been analyzed according to the Knee Society Scoring System. The subjective results have been analyzed with the Oxford Knee Questionnaire. The accuracy of implantation has been analyzed on post-operative antero-posterior and lateral long leg X-rays. The 2-year survival rate has been calculated.
INTRODUCTION
Revision total knee replacement (TKR) is a challenging procedure, especially because most of the standard bony and ligamentous landmarks used during primary TKR are lost due to the index implantation. However, as for primary TKR, restoration of the joint line, adequate limb axis correction and ligamentous stability are considered critical for the short- and long- term outcome of revision TKR. Navigation system might address this issue.
MATERIAL AND METHODS
We are using an image-free system (ORTHOPILOT TM, AESCULAP, FRG) for routine implantation of primary TKR. The standard software was used for revision TKR. Registration of anatomic and cinematic data was performed with the index implant left in place. The components were then removed. New bone cuts as necessary were performed under the control of the navigation system. The system did not allow navigation for intra-medullary stem extensions and any bone filling which may have been required. This technique was used for 37 patients. The accuracy of implantation was assessed by measuring following angles on the post-operative long-leg radiographs: mechanical femoro-tibial angle, coronal orientation of the femoral component in comparison to the mechanical femoral axis, coronal orientation of the tibial component in comparison to the mechanical tibial axis, sagittal orientation of the tibial component in comparison to the proximal posterior tibial cortex.
Individual analysis was performed as follows: one point was given for each fulfilled item, giving a maximal accuracy note of 4 points. Prosthesis implantation was considered as satisfactory when the accuracy note was 4 (all fulfilled items). The rate of globally satisfactory implanted prostheses and the rate of prostheses implanted within the desired range for each criterion were recorded. The results of the 37 navigated revision TKR were compared to 26 cases of revision TKR performed with conventional intramedullary guiding systems.
Total knee arthroplasty belongs today to one of the standard operation in orthopaedic surgery. During the last years the number of the total knee arthroplasty has dramatically increased. The prognosis for the future have shown also an increasing tendence. The Swedish Regiter Study and others showed that the results after total knee replacement not almost dependant on the design of the prothesis. More important are patient selection, operation technique and the postoperative therapy.
The goals of modern knee replacement surgery are restoring mechanical alignment, preserving of the joint line, balancing ligament with a well balanced extension and flexion gap to reach maximum stability and movement. Bone resection is the simple part of a total knee operation. Ligament balancing with equal extention and flextion gap represents a major chalange for the surgeon which may consequantly affect the stability both in extention and flextion. Stability of total knee arthroplasty is dependant on correct and percise rotation of the femoral component. Femoral component malrotation has been associated with numerous adverse sequelae, including patellofemoral and tibiofemoral instability, knee pain, arthrofibrosis, and abnormal knee kinematics. A great number of early revision today are due to malrotation of the femoral component.
Multiple differing surgical techniques are currently utilized to perform TKA. femur first (measured resection) tibia first (gap balancing)
In the classic femur first technique the excision of the bone done indepentaly after one another followed by ligament balancing in flextion and extension. There are 4 bony landmarks deciding the rotational position of the femur. The epicondylar line, whiteside line, the dorsal condyles and anetroir-posterior axis. All these landmarks are associated with problems and failure to define exactly these bony landmarks intraoperatively. This may lead not seldom to malrotation of the femural component, consequently instability, limitation of function and increased wear.
In the tibia first technique excision of the femur especially for flexion done dependant on the excision of the tibia. This carried out using a tensor. With using this technique the rotation of the femur will be oriented mainly at the ligament balancing espcialy in flexion. Flexion instability and patellae maltacking will be avoided.
We present our preferrd tibia first technique using a new tensor system. With this system it is possible to reach a well balanced extension and flextion gap. A 3° release is only needed in special cases. The rotation position of the femur depend primerly on the released soft tissue in extension. Also an exact reconstruction of the dorsal offset as well as an exact anterior or posterior referencing can be guaranteed with the instruments by infinitely variable ap movement. The use of bony landmarks also possible.
we think our new tensor present a step forwards in understanding the biomechanics of the knee and offer a new development of the instruments used in knee replacement. This could be useful especialy in cases of revision.
Today TKA belongs to a standard care in orthopaedics and traumatology. The number of the annual implantations has clearly increased during the last years and also in the future an increasing rate to be expected.
Also the number of Revision TKA and the treatment of complicated pathologies in the primary care will increase in the same way.
Therefore the requirements of the surgeon rised as well as a suitable and accurate systems will be needed. Beside revision cases, traumatic-, post-traumatic- and RA-patients demonstrate partly distinctive bone and ligamentous pathologies.
Beside the primary implant components and instrumentation-systems, modern knee systems must include also modular revision systems compatible with the primary systems to be able to carry out complicated primary as well as light to moderately severe recision cases. Besides, also the possibility should be able to change within the system (with constant bone-cuttings) on higher degrees of the constrain.
With the TC-Primary and TC-Revision system fulfils the above mentioned criteria so that nearly every situation can be handled.
We present our experience using this system in cases of revisions, traumatic, post-traumatic and RA-cases The handling of bone and ligamentous defects will be demonstrated. In particular the possibility the use of the TC-Revision also in primary TKA as P a so named “extension primary system” will be emphasized.
By the Modulary and compatibility of the TC-Primary and TC-Revision systems, the use of Wedges and Stems as well as the possibility of the different degrees of the constrain a knee family permits us to treat complicated primary as well as mild to moderate revision cases.
We report on our experience of a THR program set up in Ouagadougou, Burkina Faso (BF). As THR is not performed on a regular basis in this country, we had to start it up completely. We work in BF during a 2 weeks period in December each year. We do this in coöperation with a local surgeon who makes a preselection of THR candidates in advance. This surgeon is trained by us to do the necessary follow up and can contact us all year round in case of specific problems. From 2004 until 2009 we performed 104 operations; these consisted of 98 THR, 2 bipolar hip replacements and 4 revisions. 3 of these revisions were of hip replacements performed by us; 1 revision was of a THR performed in France. Mean age at operation was 48,4 years. All operations were performed by an anterolateral approach with use of cemented implants. Reason for operation was degenerative arthritis in 31 (29,8%), AVN in 39 (37,5%), fracture in 30 (28,9%). Fractures were more than several months old in most cases. Reason for the revision operations was aseptic loosening in 3 cases and periprosthetic fracture in 1.
For every operation, technical problems were recorded, if applicable. These problems were not necessarily complicatons. We recorded 50 technical problems in 31 patients. 73 operations (70,2%) were performed without any note of technical problem. Most frequently recorded problems were important shortening of the leg (6), very narrow femoral canal (6), difficult reduction (5), peroperative femoral fracture (4-excluding trochanter maior fracture), extensive fibrosis (4), blocked femoral canal (3).
Flexible reamers were used in 5 cases.
There were 2 peri-operative deaths: one patient died after a postoperatieve sickle cell crisis with hemolysis. One patient developed a pulmonary embolism. Both patients were Hb SC.
We recorded 21 complications in 16 patients. The majority were osseous complications. These were 4 femoral fractures of which 3 had clinical repercussion, 4 trochanteric fractures without any clinical repercussion and 4 peroperative perforations of the femoral canal, all without postoperative clinical repercussion. Other complications were infection (2), paralysis of femoral nerve (1), burn injury by diathermia plate (1), postoperative hemolysis (1), pulmonary embolism (1) and dislocation (2). One infection and dislocation was found in the same patient. This was the patient with revision of a initial THR performed in France.
The indications for THR in BF differ significantly form the indications we find in Belgium. We also find the average case in BF more challenging. During the years we have developed specific strategies and schemes based on our experience and the technical problems encountered during the operations.
Specific tips and tricks regarding patient selection, technique and equipment will be presented. This can be a good opportunity to learn from our experience for anyone who wants to set up a similar program.
Revision total hip replacements are likely to have higher complication rates than primary procedures due to the poor quality of the original bone. This may be constrained to achieve adequate fixation strength to prevent future “aseptic loosening” [1]. A thin, slightly flexible, acetabular component with a three dimensional, titanium foam in-growth surface has been developed to compensate for inferior bone quality and decreased contact area between the host bone and implant by better distributing loads across the remaining acetabulum in a revision situation. This is assumed to result in more uniform bone apposition to the implant by minimizing stress concentrations at the implant/bone contact points that may be associated with a thicker, stiffer acetabular component, resulting in improved implant performance.[2] To assemble the liner to the shell, the use of PMMA bone cement is recommended at the interface between the polyethylene insert and the acetabular shell as a locking mechanism configuration may not be ideal due to the flexibility in the shell [3].
The purpose of this study was to quantify the mechanical integrity of a thin acetabular shell with a cemented liner in a laboratory bench-top total hip revision condition. Two-point loading in an unsupported cavity was created in a polyurethane foam block to mimic the contact of the anterior and posterior columns in an acetabulum with superior and inferior defects. This simulates the deformation in an acetabular shell when loaded anatomically [4]. The application has been extended to evaluate the fatigue performance of the Titanium metal foam Revision Non-Modular Shell Sequentially Cross Linked PE All-Poly Inserts and its influence on liner fixation.
The purpose of this study is to investigate the feasibility of surgical correction of moderate flexion deformity during total knee arthroplasty by recreating the posterior condylar recess following certain sequence of surgical principles without extra-resection of bone from the distal femur or proximal tibia. The hypothesized surgical protocol was applied in 52 consecutive primary TKAs with moderate flexion deformity. Preoperative and residual postoperative flexion deformity was recorded. Intraoperatively, extension and flexion gap widths were recorded before and after surgical correction. Fixed flexion deformity has improved from a preoperative mean value of 24.8±6.4 to a postoperative residual value of 3.2±1.8 (p value < 0.001). Extension and flexion gap widths have increased by a mean value of 3.8±0.4 mm and 4.1±0.7 mm respectively (p value < 0.005). There was no significant difference between the changes in the extension and flexion gaps. The original flexion/extension gap width mismatch (3.2±0.5mm) was compensated for by an upsized femoral component. The statistically significant changes has demonstrated the efficiency of the hypothesized surgical protocol for management of flexion deformity during TKA added to the benefits of bone conservation for future revision surgery, preservation of surface area for collateral attachments, and establishment of the joint line at the correct level.
Two-stage revision arthroplasty is the gold standard for treatment of infection after total hip Arthroplasty and end stage septic arthritis of the hip. In the first stage we used a modified technique to insert an inexpensive modular femoral component coated with antibiotic-impregnated polymethylmethacrylate articulating with a polyethylene liner. The construct was used in 8 patients with infected arthroplasty, and 6 patients with septic arthritis of the hip. Two patients were excluded (no second stage). Of the remaining 12 patients, only one patient had persistent infection after the first stage; 11 patients received a successful re-implantation at the second-stage. The technique provide a construct that can be used safely and successfully in the awaiting period between the two stages of revision arthroplasty.
Background
High cup abduction angles generate increased contact stresses, higher wear rates and increased revision rates. However, there is no reported study about the influence of cup abduction on stresses under head lateralisation conditions for ceramic-on-Ceramic THA.
Material and method
A finite elements model of a ceramic-on-ceramic THA was developed in order to predict the contact area and the contact pressure, first under an ideal regime and then under lateralised conditions. A 32 mm head diameter with a 30 microns radial clearance was used. The cup was positioned with a 0°anteversion angle and the abduction angle was varied from 45° to 90°. The medial-lateral lateralisation was varied from 0 to 500 microns. A load of 2500 N was applied through the head center.
INTRODUCTION
Squeaking after total hip replacement has been reported in up to 10% of patients. Some authors proposed that sound emissions from squeaking hips result from resonance of one or other or both of the metal parts and not the bearing surfaces. There is no reported in vitro study about the squeaking frequencies under lubricated regime. The goal of the study was to reproduce the squeaking in vitro under lubricated conditions, and to compare the in vitro frequencies to in vivo frequencies determined in a group of squeaking patients. The frequencies may help determining the responsible part of the noise.
METHODS
Four patients, who underwent THR with a Ceramic-on-Ceramic THR (Trident(r), Stryker(r)) presented a squeaking noise. The noise was recorded and analysed with acoustic software (FMaster(r)). In-vitro 3 alumina ceramic (Biolox Forte Ceramtec(r)) 32 mm diameter (Ceramconcept(r)) components were tested using a PROSIM(r) hip friction simulator. The cup was positioned with a 75° abduction angle in order to achieve edge loading conditions. The backing and the cup liner were cut with a diamond saw, in order to avoid neck-head impingement and dislocation in case of high cup abduction angles (Figure1). The head was articulated ± 10° at 1 Hz with a load of 2.5kN for a duration of 300 cycles. The motion was along the edge. Tests were conducted under lubricated conditions with 25% bovine serum without and with the addition of a 3rd body alumina ceramic particle (200 μm thickness and 2 mm length). Before hand, engineering blue was used in order to analyze the contact area and to determine whether edge loading was achieved.
Background
A high precision of three-dimensional (3D) computerised planning of THA was recently reported. However, there is no comparative study analysing the value of 3D planning comparatively to the planning made on X-rays using 2D templates
Material and method
A prospective comparative randomised study was carried out from 2008 to 2009, and included 2 groups of 32 patients who underwent THA for primary osteoarthritis. One surgeon performed all the procedures using a direct anterior approach. In one group, the planning was made on calibrated X-Rays using 2D templates. In the other group, a 3D planning was performed based on CT-scan using the Hip-Plan software. Post operatively, the final hip anatomy was analysed on X-Rays for the 2D group and on CT-scan for the 3D group.
Introduction
The Oxford Knee Score is a well validated, commonly used scoring system. Previous studies have suggested that the score is influenced by demographic differences between patients in particular the functional component more than the pain and clinical components. The aim of this study was to further assess this using a large number of patients.
Methods
The pre, 3 months and 12 months post-surgical Oxford Knee Scores were collected from 1492 patients from five distinct demographic locations undergoing total knee arthroplasty over twelve years under the care of 8 different consultants. A total of 735 patients had complete data sets. The scores were than analysed to test whether age, postcode, sex or consultant in charge had any significant effects on the outcome.
In this study we reviewed all Total Elbow Replacements (TER) done in our hospital over eight years period (1997 – 2005), 21 patients (16 females, 5 males) were available for follow up and four were lost (two died and two moved out of the region) with average age of 65 years (range 44 – 77), all procedures were done by two upper limb surgeons (CHB & RGW). 16 patients (14 females, 2 males) had the procedure for Rheumatoid Arthritis and 5 patients (3 males, 2 females) undergone the procedure for post-traumatic arthritis.
The average follow up was 61 months (range 12 – 120 months), the Mayo Clinic performance index, the DASH scores and activities of daily living (adopted from Secec Elbow Score) assessment tools were used. In addition, all patients were assessed for loosening using standard AP and lateral radiographs. Sixteen patients had Souter-Starthclyde prosthesis whilst three had Kudo and two had Conrad-Moorey prosthesis.
All procedures were done through dorsal approach and all were cemented, the ulnar nerve was not transposed in any of the cases. The average elbow extension lag was 27 degrees (range 15 – 35) with flexion up to 130 degrees (range 110 – 140). Supination was 65 degrees (range 15 – 90) and pronation was 77 (range 55 – 90). The average DASH score was 51.3 (range 19 – 95), the Mayo elbow score was 82 (range 55 – 100) and the average Activities of daily living Secec Score was 17 (range 10 – 20).
There were four complications, three ulnar nerve paresis which recovered and one wound complication which needed a flap cover. Two needed revision surgery, one for a periprosthetic fracture and one for loosening. Two patients showed radiological signs of loosening but were asymptomatic. The survival rate with revision as the end point is 95% for aseptic loosening and 90% for any other reason.
Our study proves TER has good medium term results with good functional outcome and high patient satisfaction rate.
Between 2002 and 2009, 15 patients with periprosthetic fractures of the femur and the acetabulum either intraoperative or perioperative fracures were treated.
The intraoperative femoral fracture was treated by circulage and longer stems with excellent results, the postoperative femoral fracture was treated by cable plate systems or revision arthroplasty without the use of cortical strut allograft, all the cases are treated according to Vancouver classification.
There are tow cases of intraoperative acetabular fractures, the first one was treated by block autograft and cemented cup, the other one treated by multihole cementless cup as internal plating.
The postoperative acetabular fractures are spontaneous fractures due to osteolysis and treated by impaction or allograftwith metal support either by rings or meshes.
Between 2001 and 2010, 120 cases of femoral revisions were done, these cases were treated by one of the following three techniques; the first one is revision by long stem cemented, the second is revision by long stem cementless with the use of oscar system through endofemoral application and the third is revision by long stem cementless via Wagner osteotomy, one of these patients was treated by long stem cemented as primary treatment due to proximal femoral deficiency.
All of the long stem revisions were treated without the use of strut cortical allograft as this type of graft is not available in Egypt.
The choice of the implant depends on the type of the primary prosthesis, bone quality, proximal femoral deficiency and the technique of removal.
40 patients affected by primary and secondary acetabular bone stock defect that were operated using cemented and cementless hip replacement.
Bone defect was classified according to American Academy of orthopaedic surgery, different types of bone graft techniques and metal reinforcement were used.
Geometrical position of the acetabular component, cup integration, hip center and graft interposition were assessed, 95% of the cups were in the desired position with graft incorporation and remodeled with one case of partial sciatic affection, most of reconstructions in primary hips were done with cementless cups but most of reconstructions in defects following loosening were treated by cemented cups.
The results depend on the stability of the graft, cementing technique as well as cup position.
This Outcome Studies Software suite has been designed and carried out by Surgeons for Surgeons in order to provide the Orthopaedic Community with a valuable tool devoted to the computerized clinical follow-up of Joint Arthroplasty, named OrthoWave(tm). The development of the OrthoWave(tm) suite, since 1996, has got involved clinical studies coordinators, software engineers, orthopaedic surgeons, and statisticians.
One underlying theme regarding Health Care has and always will be constant: the need to understand if our treatments actually work. Providing answers makes not only scientific sense but pragmatic and economic sense as well. In such a way, Evaluation in Joint Arthroplasty has become a master word in the realm of Orthopaedic Surgery, which thus gets many actors involved, be they Surgeons, Scientific Societies, Health Department Authorities, Journal Editors, and Orthopaedic Devices Manufacturer.
While bearing in mind that more than a million of Hip and Knee replacements are worldly performed annually and there are thousands of devices and device combinations in use to achieve arthroplasties, these replacement procedures have to be properly evaluated as a very challenging procedure. An outcomes study software needs to allow for easy and user friendly collection of clinical data and related images, while preserving privacy of patients and their personal data. This software must then provide consistent statistical and survivorship analyzes in the very long run. The OrthoWave(tm) software has been widely used worldly, and currently features the on-line Version 6, now available as a web-based secured “cloud computing” computer system. The so called “regular databases” can be linked to additional “scientific databases” and “monitored databases” able to set up together a very consistent and efficient global system.
Roughly speaking, OrthoWave addresses (1) data collection of Surgeons themselves, able to self evaluate their surgeries while owning their own data, (2) Local Registries, involving groups of Surgeons, to analyze, report and publish clinical series in the Literature, (3) Brand Registries, for tracking upon large multicenter studies at an early stage any problem that might occur with any given implant, (4) Clinical Affairs Departments in Industry, (5) and finally enables potential automatic links to National and International Joint Registries.
This OrthoWave software has thus permitted a “fine tuning” of clinical results, radiographic findings, survival rates and real assessment of quality of life, helping to determine in large databases studies if implant composition or joint replacement features can be associated with decreased need for repeat surgery, and to outline best methodological approaches to the assessment of failures in arthroplasty, in terms of functioning, quality of life and long-term disability.
All along these 14 years of continuous use of this OrthoWave software suite, we have tried to help it to be more and more efficient and user friendly. The current on-line web-based version now meets our expectation, and is flexible enough to adapt itself to future needs and better treatments for patients.
Non-cemented components have traditionally employed several possible features, among them a stem and/or collar, to achieve proper alignment and initial implant stability within the proximal femoral cavity.
The advent of MIS has stimulated an interest in reducing the dimensions of implants, specifically stem length, in order to facilitate introduction and implantation of the component. The consequence of this trend appears to be an increase in early aseptic failure, of some components, due to loosening and migration. Several important questions have arisen. What are the direction of the deforming forces about a hip during daily activities? What design features should a short stem implant exhibit so as to provide optimum stability against these forces? Is having a stem an absolute requirement of a femoral component? What is the minimum “safe” length a stem must have? How can proper short stem alignment be optimized? Is intra-operative x-ray exposure necessary?
This presentation will discuss the computer modeling, laboratory testing and clinical outcomes of various
component designs; and make suggestions concerning directions for future investigations.
Objectives
Few reports were shown about the position of the cup in total hip arthroplasty (THA) with CT-based navigation system. We use minimally invasive surgery (MIS) technique when we perform cementless THA and the correct settings of cups are sometimes difficult in MIS. So we use CT-based navigation system for put implants with correct angles and positions. We evaluated the depth of cup which was shown on intra-operative navigation system.
Materials and Methods
We treated 30 hips in 29 patients (1 male and 28 females) by navigated THA. 21 osteoarthritis hips, 6 rheumatoid arthritis hips and 3 idiopathic osteonecrosis hips were performed THA with VectorVision Hip 2.5.1 navigation system (BrainLAB). Implants were AMS HA cups and PerFix stems (Japan Medical Materials, Osaka). Appropriate angles and positions of cups were decided on the 3D model of pelvis before operation. According to the preoperative planning, we put the implants with navigation system. We correct the pelvic inclination angle and measured the depth of cups with 3D template software.
INTRODUCTION
The majority of papers covering MIS total knee describe a surgical approach where the quads tendon is violated. This presentation describes a modified subvastus approach using MIS technique. The results are compared to the regular subvastus approach.
MATERIAL AND METHODS
423 total knee replacements were performed through MIS subvastus approach from November 2002 to February 2004. All cases were performed by the same surgeon. The subvastus approach was modified to allow more quads excursion so the surgery can be performed without dislocating the patella. The data was processed at University of Dundee. The results were compared to the results of 361 cases of standard subvastus approach performed by the same surgeon.
INTRODUCTION
The majority of implants available in the market today were designed to allow for a flexion up to 130 degree angle. The LPS Mobile Flex was designed to accommodate deep flexion, up to 160 degree angle. The purpose of this study is to evaluate the clinical result of the LPS Mobile Flex knee.
MATERIALS AND METHODS
From January 1999 to February 200, 1043 (one thousand and forty three) surgeries were performed on patients treated for advanced osteoarthritis. All the surgeries were carried out by the same surgeon. The majority of the patients had bilateral total knee replacements simultaneously. Mobile and fixed implants were used. Pre-operative ranges of motion were documented on lateral x-ray. Patients were considered to have full flexion if they were able to flex the knee to at least 140 degree and sit on the ground with calf touching thigh for at least one minute. Data were processed at University of Dundee
INTRODUCTION
The majority of implants available in the market today were designed to allow for a flexion up to 130 degree angle. The LPS Mobile Flex was designed to accommodate deep flexion, up to 160 degree angle. The purpose of this study is to evaluate the clinical result of the LPS Mobile Flex knee.
MATERIALS AND METHODS
From January 1999 to Febuary 2002, 318 surgeries were performed on patients treated for advance osteoporosis. All the surgeries were carried out by the same surgeon. The majority of the patients had bilateral total knee replacements simultaneously. Pre-operative ranges of motion were documented on lateral x-ray. Patients were considered to have full flexion if they were able to fix the knee to at least 140 degree angle sit on the ground with calf touching thigh for at least one minute.
Introduction
The number of total knee joint replacements has increased dramatically, from 28,000 in 2004 to over 73,000 in 2008 in the UK. This increase in procedures means that there is a need to assess the performance of an implant design in the general population. For younger, more active patients, cementless tibial fixation is an attractive alternative means of fixation and has been used for over 30 years. However, the clinical results with cementless fixation have been variable, with reports of extensive radiolucent lines, rapid early migration and aseptic loosening [1]. This study investigates the inter-patient variability of bone strain at the implant-bone interface of 130 implanted tibias over a full gait cycle.
Methods
A large scale FE study of a full gait cycle was performed on 130 tibias implanted with a cementless tibia tray (PFC Sigma, DePuy Inc, USA). A population of tibias was generated from a statistical shape and intensity (SSI) model [2].
The tibia tray was automatically positioned and implanted using ZIBAmira (Zuse Institute Berlin, Germany). Cutting and implanting were performed using Boolean operations on the meshed surfaces of the tibia and implant. After generation of a volume mesh from the resulting surface, the bone modulus was mapped onto the new mesh.
The FE models were processed in Abaqus (SIMULIA, RI, USA). Associated force data (axial, anterior-posterior and medial-lateral forces and flexion-extension, varus-valgus and internal-external moments) was sampled from a statistical model of the gait cycle derived from musculoskeletal modelling of 20 elderly healthy subjects. Patient weight was estimated using the length of the tibia and a BMI sampled from NHANES data.
Loads were applied to four groups of nodes on the tibia tray (anterior, posterior, medial and, lateral) for 51 steps in the gait cycle. The bone and implant were assumed to be bonded, simulating the osseointegrated condition.
Introduction
the aim of this study was to analyse the long-term radiological changes following tsa in order to better understand the mechanisms responsible for loosening.
Material and methods
between 1991 and 2003, in 10 European centers, 611 shoulder arthroplasties were performed for primary osteoarthritis using a third generation anatomic prosthesis with a cemented all-polyethylene keeled glenoid component. Full radiographic and clinical follow-up greater than 5 years was available for 518 shoulders. Kaplan-meier survivorship analysis was performed with glenoid revision for loosening and radiological loosening as end points; clinical outcome was assessed with the constant score, patient satisfaction score, subjective shoulder value and range of movement
Introduction
Revision surgery is generally recommended for recurrent dislocation following Total hip arthroplasty (THA). However, dislocation following revision THA continues to remain a problem with further dislocation rates upto 28% quoted in literature.
We present early results of one of the largest series in U.K. using dual mobility cemented acetabular cup for recurrent hip dislocation.
Methods
We retrospectively evaluated 40 patients where revision of hip replacement was performed using cemented dual mobility acetabular prosthesis for recurrent dislocations from March 2006 till August 2009 at our district general hospital by a single surgeon (senior author). The series comprised of 13 men and 27 females with average age of 73.4 years (49-92). The mean follow-up period was 23 months. (36 months –6 months).
All the hips that were revised had 3 or more dislocations, some them more than 10 times. The cause of dislocation was multifactorial in majority of cases including acetabular component malpositioning mainly due to loosening and wear. A cemented dual mobility cup was used in all cases. In six cases the femoral stem was also revised.
Introduction
A 68 year old female patient underwent a left total hip replacement for primary osteoarthritis in March 2004. She was referred back by her GP 5 years as she was struggling with mobility and felt there were mice in her hip. It was squeking so loudly that it could be hear at a distance of 25 metres. There was no history of any falls or dislocation in the last 5 years. The implant used was an Exeter/ABG ceramic total hip prosthesis with Palacos cement. This ladies discomfort in her hip had been always there. She never described herself as being satisfied with the THR. However, her discomfort had worsened terribly over the last year.
On examination
The slightest movement around her hip caused her severe pain. Tremendous squeaking could be heard when she was made to walk. She had significantly limb length discrepancy of 2.5cms. The radiographs revealed that she had probably broken the ceramic head as pieces could be seen around the neck area.
Collo MIS is a new short stem created to achieve minimal metaepiphyseal invasiveness, to respect the joint physiology, to get optimal primary stability and osteointegration.
This stem needs a subcapital osteotomy to respect and preserve the physiologic anteversion of the femoral neck; the technique provide compactation of the cancellous bone of the greater trochanter using just compactors and not rasps during the femur preparation and the stem has to match the calcar curvature to get the right position.
This stem has been designed with a lateral wedge to ensure a great primary stability in the femoral neck.
Since November 2008 at Niguarda Hospital we have implanted 350 prosthesis in cooperation with Frankfurt Hospital.
Patients age varies form 26 to 80 years old with a mean age of 61 y.o.
This stem has to be implanted in patients with good bone quality to achieve the compactation of the cancellous bone.
We have operated patients affected mostly by coaxrthrosis and just in few cases by dysplasia (Crowe 1); contraindications are represented by a CCD angle less than 120° and more than 140° because of the stem morphology, severe osteoporosis, dymorphism, and dysplasia (Crowe 2,3,4).
We have evaluated the offset and CCD angle pre and post op that resulted mostly increased after surgery (average CCD angle +6,15°, offset + 5.95 mm).
In the post-op we normally give partial weight bearing after 1 day and the full weight bearing after 20 days.
The mean HSS score before surgery was of 57.5 points and after 1 year of 98 points.
The complications we have found in these study were: 11 cases of dysmetrias less than 1 cm, 6 cases of neck fissuration. No infection, mobilization, neck impingemen, subsidence, radiolucency have been evaluated.
Introduction
The aim of this study is to report the results of Revision hip arthroplasty using large diameter, metal on metal bearing implants- minimum 2 year follow up.
Methods
A single centre retrospective study was performed of 22 consecutive patients who underwent acetabular revision surgery using metal on metal bearing implants between 2004 and 2007. Birmingham hip resurfacing (BHR) cup was used in all patients - monoblock, uncemented, without additional screws in 16 cases and cemented within reinforcement or reconstruction ring in 6 cases.
Femoral revisions were carried out as necessary.
Introduction
To report the short to medium term results of acetabular reconstruction using reinforcement/reconstruction ring, morcellised femoral head allograft and cemented metal on metal cup.
Methods
Single centre retrospective study of 6 consecutive patients who underwent acetabular reconstruction for revision hip surgery.
The acetabulum was reconstructed using morcellised femoral head allograft and reinforcement or reconstruction ring fixed with screws. The Birmingham cup – designed for cementless fixation, was
Data from our previous in-vitro study had shown good pull out strength of a cemented Birmingham cup.
Non-invasive expandable prostheses for limb salvage tumour surgery were first used in 2002. These implants allow ongoing lengthening of the operated limb to maintain limb-length equality and function while avoiding unnecessary repeat surgeries and the phenomenon of anniversary operations.
A large series of skeletally immature patients have been treated with these implants at the two leading orthopaedic oncology centres in England (Royal National Orthopaedic Hospital, Stanmore, and Royal Orthopaedic Hospital, Birmingham).
An up to date review of these patients has been made, documenting the relevant diagnoses, sites of tumour and types of implant used. 87 patients were assessed, with an age range of 5 to 17 years and follow up range of up to 88 months.
Primary diagnosis was osteosarcoma, followed by Ewing's sarcoma. We implanted distal femoral, proximal femoral, total femoral and proximal tibial prostheses. All implants involving the knee joint used a rotating hinge knee. 6 implants reached maximum length and were revised. 8 implants had issues with lengthening but only 4 of these were identified as being due to failure of the lengthening mechanism and were revised successfully. Deep infection was limited to 5% of patients.
Overall satisfaction was high with the patients avoiding operative lengthening and tolerating the non-invasive lengthenings well. Combined with satisfactory survivorship and functional outcome, we commend its use in the immature population of long bone tumour cases.
One cementless cup which had porous outer surface with Apatite-Wollastonite glass ceramic (AWGC) coating, was revised 13 years after primary THA because of massive osteolysis expanded to medial iliac wall along the screws. While many retrieved studies of hydroxyapatite-coated cup have been reported, there has been no report on the retrieved cup with AWGC coating. The purpose of this study was to describe this rare case in detail, confirm the bone ingrowth to the porous cup, and discuss on the effectiveness of porous surface with AWGC coating.
Case
The patient was a 64 old woman and complained of chronic mild pain around her left groin region. X-ray examination revealed that osteolysis had been expanding around the screws and extended proximally. The revision surgery was performed for the massive osteolysis through Hardinge antero-lateral approach. The retrieved implants included a cementless cup made of titanium alloy (QPOC cup, Japan Medical Materirals Inc.(JMM) Osaka, Japan), the outer surface of which was plasma-sprayed with titanium for porous formation and coated with AWGC in the deep layer. It was found that the polyethylene liner was destructed partially in the supero-lateral portion, but the cup was well fixed to the bone. The bone-attached area was found to be dispersed over the porous surface of the hemispherical cup. Histological examination revealed that matured bony tissue intruded into the porous surface of the cup, and contacted to bone directly, which was also demonstrated in the back-scattered electron image. It was also demonstrated that there were residual silicon (Si) rich regions on the porous surface by the SEM-EDX analysis, which indicated that constituents of AWGC still remained on the surface. On the other hand, the results of elementary analyses in the Si rich regions varied among the sections, which probably indicated that the extent of degradation and absorption of AWGC varied among the sections.
AWGC was one of the bioactive ceramics and reported to have an ability to bond to bone earlier than hydroxyapatite (HA). In the present case, though massive osteolysis occurred with aggressive wear, it did not expand on the porous surface, and rather progressed along the smooth surface of the screws. Considering that there are many clinical studies reporting poor clinical results of HA-coated smooth cups, bioactive ceramic coating may function well and bring superior clinical results when combined with porous coated substrate. In our study, though the cause of massive polyethylene wear and intrapelvic giant osteolysis could not be revealed, the porous cup with AW-GC bottom coating was well fixed and gained bone-ingrowth at the porous surface under osteolytic conditions, which may demonstrate the long-term durability of this surface treatment.
Introduction
Reoperations to manage unstable total hip arthroplasty are reported with a high failure rate. The dual mobility cup (figure 1) (mobile polyethylene component between the prosthetic head and the outer metal shell) is a useful option in such cases. The purpose of this retrospective study was to assess the clinical and radiologic features associated with the dual mobility cup.
Materials and Methods
Fifty one unstable total hip arthroplasties (32 females, 19 males) were revised using a dual mobility socket at our institution between March 2000 and February 2005.
Mean age at reoperation was 67 year old (range, 35 to 98). The outcome of the revision procedure was assessed using the Harris Hip Score, and complications were determined by detailed review of the patient's records. Anteroposterior and lateral radiographs of the involved joint were reviewed to assess the position of the prosthesis and to look for osteolysis and signs of loosening of the implant.
Introduction
Recurrent instability after total hip arthroplasty remains a serious and somewhat frequent problem. Constrained implants have proven effective to manage instability. This has led to a liberal utilization of these devices. However, sporadic mechanical failures have been reported. This report analyzes the failures of a single constrained device at our institution.
Materials and Methods
Forty-three constrained implants (Stryker Constrained Liner™) in 34 patients were revised out of total 390 similar implants performed at our institution. There were 24 females and 10 males. Constrained implant was inserted at the first revision in 6 hips and after an average of three surgeries (1-6) in 37 hips. Seven different methods of constrained liner fixation were observed. Eight different theoretical failure mechanisms were identified: six are mechanical device failures at each of the implant interfaces, infection and catastrophic polyethylene wear being the other two.
Introduction
Despite improvements in prosthesis design, the clinical outcome of total hip arthroplasty still has 10% failure rate after 10 years. Component malpositioning can lead to instability, impingement, excessive wear and loosening. Computer-assisted procedures are expected to improve the accuracy of component positioning, and therefore the long-term outcome. We present an original hip navigation system that allows controlling leg lengthening, offset and stability without the use of the pelvic anterior plane.
Material and Methods
Because the reliability of the pelvic anterior plane (Lewinnek plane) remains discussed, we present a computer-assisted hip replacement using a functional femoral reference plane. Direction and depth of the acetabular reaming and progression of the femoral rasp are calculated by a sophisticated algorithm, as well as the components' final position, in order to control leg lengthening and offset. In addition, the ROM to impingement (and therefore the stability) is continuously displayed relative to the position of the components. Simple graphical and numerical data in addition to virtual instruments displayed on the screen aid the surgeon during the entire procedure.
Digital templating was used in 50 patients who underwent THA using Merge Ortho software, Cedara. Clinical examination was performed first, to measure leg lengths and account for pelvic obliquity and flexion deformity. Good quality digital radiographs were obtained with anteroposterior and lateral views extending beyond the tip of the femoral component and the cement restrictor. A coin was placed on the ASIS to help in determining radiological magnification
Digital radiographs were saved in DICOM format and imported to EndoMap software system.
A 6-step technique was used for templating as follows:
Intraoperatively, the surgeon performed the femoral neck osteotomy at the level determined by preoperative templating. Postoperatively, the leg length was measured and compared to the preoperative leg length. Preoperatively, the leg length discrepancy ranged from 5 to 30 mm. In all cases, the leg was short on the side of THR (ipsilateral). Leg length discrepancy was adjusted in all THR cases. Postoperatively, the accuracy of the correction was found to be within 5 millimeters i.e. less than 5mm of shortening or lengthening). Intraoperatively, the level of femoral neck cut ranged from 1 to 44 mm.
Digital templating is useful in adjusting leg length discrepancy. In addition, there were other benefits such as predication of femoral and acetabular implant sizes, restoration of normal hip centre, and optimization of femoral offset.
Introduction
There is a controversy with regard to the treatment of osteoarthritis (OA) of the knee in patients with considerable deformities of the femoral or tibial shafts. Some surgeons prefer to correct the deformity while performing TKA at the level of the knee joint. However, this technique requires accurate planning and execution of the planned cuts. In addition, the use of intramedullary guides in such cases may not be possible or desirable and may lead to complications. There is a strong indication for using navigation in such cases.
Methods
The navigation technique was used in both laboratory and clinical setting, First, we compared between navigational and conventional techniques in performing TKA in 24 plastic knee specimens (Sawbones, Sweden) that have osteoarthritic changes and complex tibial or femoral deformities. A demo kit for conventional instrumentation of posterior stabilised TKA (Scorpio, Stryker) was used for 12 cases and an image-free navigation system (Stryker) was used for a corresponding 12 cases. There were 4 different deformities; severe mid-shaft tibial varus, severe distal third femoral valgus, complex deformity distal femur and deformity following a revision TKA. The surgical procedures were performed by 3 arthroplasty surgeons, each surgeon operated on 8 knee specimens (4 knees in each arm of the study with 4 different deformities). Deformities were corrected at the level of the knee joint during TKA without prior osteotomies. For conventional techniques, surgeons used a combination of both intramedullary and extramedullary guides. Postoperative long leg radiographs were used to assess coronal alignment. Second, we used the same navigational technique clinically to perform TKA in patients with extra-articular deformities.
Some mobile bearing knee replacement designs have shown truly excellent long-term clinical results. The higher laxity of a mobile bearing helps reduce the shear forces and torques transmitted to the prosthesis-bone interface, and this could only help reduce the risk of loosening. Some argue that self-alignment of a mobile bearing rotationally can produce more central patellar tracking. However, the most commonly assumed benefit of mobile bearings is the reduction in contact stress, which is typically expected to reduce fatigue and wear. In a rotating platform TKR for example, wear is also expected to be less because the rolling/sliding motion is separated from the transverse rotational motion onto two separate articulating surfaces, thus less cross-paths and less wear. Such expectations may have dominated the thinking and perhaps even clouded the expectations of TKR wear test engineers. Such wear reduction however has not really been categorically proven clinically.
This paper combines in-vitro wear results from two separate laboratories, one in Nebraska USA and one in Germany. These two (industrially unattached labs) possess between them a very large set of in-vitro wear testing results across the widest variety of fixed and mobile bearing TKR designs. Fortunately, the wear testing methodology using the force-control regime used in the two labs was largely similar, and was highly consistent within each lab. The fixed and the mobile bearings were subjected to the exact same force fields, allowing their Anterior-Posterior translation and internal-external rotation kinematics to vary based on the individual TKR design.
Tens of implant designs have been tested, both fixed and mobile, in total (bycondylar) form and unicompartmental, of various sizes. Some mobile bearings had rotating platforms and some were rotating-translating. Some of the tests specifically compared mobile to fixed bearing tibial components using identical femoral components. Between both labs, and across all tests, no statistically significant difference resulted in wear between fixed and mobile bearings. Yet, such differences did clearly feature with known superior bearing materials (for wear) and other favored design features. Also, generally, the force-control test methodology has proven highly discriminatory in its simulation and measurement of wear as a potential clinical failure mode.
The take home message to test engineers is to expect the wear of both mobile and fixed bearings to depend more on the detailed design and materials of the TKR than on the mobility of the bearing. The results of this study re-confirm the need for wear testing to be performed prior to any clinical use on all implant designs, despite seemingly similar predicates or success of some mobile bearings.
Unicompartmental knee replacement components have gained favor because they replace only the most damaged areas of articular cartilage and the less invasive operation results in a faster patient recovery than traditional TKR. Additionally, they can provide a solution when a full TKR is not yet needed. However, the wear magnitude of such implants is not well understood, primarily due the variation in design and the difficulty of testing them in knee simulators designed to test full TKRs. Modern innovative partial cartilage replacement knee components which are typically even smaller and more bone conservative than unicompartmental implants, are even less common in testing with added challenges. This study investigates the fatigue characteristics of partial cartilage replacement knee components, and the wear of the UHMWPE bearing of a new, truly less invasive unicompartmental design by Arthrex Inc./Florida.
Fatigue testing was performed on MTS 858 MiniBionix machines. Two 12mm diameter UHMWPE tibial components were cemented into jigs at 0° posterior slope and were axially loaded at 2Hz for 10 million cycles (Mc) with a sinusoidal profile peaking at 60% of 8 average human bodyweights (3800N) and a load ratio R of 0.1. Two femoral components were tested with the same load profile at 10Hz for 10 million loading cycles (Mc). The femoral components were mounted at 15° flexion and only the anterior half of the implant was supported, replicating a worst-case scenario where fixation had failed on the posterior half of the implant. This resulted in a large bending moment when force was applied that would fatigue the femoral implant. Following the fatigue test, two full wear simulation tests were conducted on four 12mm and four 20mm unicompartmental components on a four-station Instron-Stanmore force-control knee simulator. The spring-based system to simulate soft-tissue restraining forces and torques was adapted to operate the machine in a displacement control mode to achieve the motions of the medial compartment based on ISO 14243-3. The specimens were lubricated with bovine serum (20g/L protein, 37°C) and the simulator was operated at 1Hz. Liquid absorption was corrected through passive-soak-control bearing inserts. The tibial specimens were cleaned and weighed at standard intervals with the usual ISO test protocols.
After 10Mc of fatigue testing, both tibial components had deformed by some flattening out but were able to sustain the full load without failure and displayed average stiffness (over the whole 10Mc) of 27,600±1,180 N/mm. Neither partially supported femoral component failed, and the femorals displayed average stiffness (over 10Mc) of 37,500 ±3,280N/mm. After 5Mc of wear testing, the 12mm tibial components displayed a wear rate of 4.56±1.45mg/Mc while the larger 20mm size wore at a lower 2.80±0.39mg/Mc.
The results from the fatigue test suggest that this unicompartmental cartilage replacement design will not fail under simple axial loading, even under the extreme case where the tibial implant is receiving the entire share of the load, and the femoral component is only partially supported. In the clinical application, of course some load-sharing with the native unworn cartilage would occur, reducing the stresses on the implant. The results from the wear test showed very low wear for tibial components of this design, lower than many successful TKRs. The larger size tibial components wore less likely due to reduced contact stress. Based on the results of this test, an implant of this type could be a viable option prior to TKR.
Introduction
The purpose of this study was to evaluate the in vivo migration patterns of a polished femoral component cemented line-to-line using EBRA –FCA.
Methods
The series included 164 primary consecutive THAs performed in 155 patients with a mean age of 63.8 years. A single prosthesis was used combining an all-polyethylene socket and a 22.2 mm femoral head. The monoblock double tapered femoral component made of 316-L stainless steel had a highly polished surface (Ra 0.04 micron) and a quadrangular section (Kerboull(r) MKIII, Stryker). The femoral preparation included removal of diaphyseal cancellous bone to obtain primary rotational stability of the stem prior to the line-to-line cementation. Stem subsidence was evaluated using EBRA-FCA software which accuracy is better than ± 1.5 mm (95% percentile), with a specificity of 100% and a sensitivity of 78% for detection of migration of more than 1.0 mm, using RSA as the gold standard.
Introduction
The purpose of this prospective randomized study was to compare the 2-year follow-up penetration of Oxinium versus Metal on polyethylene in a consecutive series of low friction total hip arthroplasty.
Methods
Between July 2006 and May 2006, 50 patients (27 females and 23 males) with a mean age of 60.6 ± 11.4 years (21 to 75) were randomized to receive either Oxinium (25 hips) or Metal (25 hips) femoral head. Other parameters, including the femoral component and the all polyethylene socket (EtO sterilized), were identical in both groups. The primary criterion for evaluation was linear head penetration measurement using the Martell system.
Introduction
Several devices based upon the dual mobility (DM) concept have recently been FDA approved. However, little is available on the efficiency of current DM on THA instability prevention, and on specific complications. The aim of this retrospective study was to report on the minimal 5-year follow-up results of a cementless DM socket.
Methods
Between January 2000 and June 2002, 168 primary consecutive non selected THAs were performed in 92 females and 76 males. The average age at surgery was 67.3 years. A single DM socket design was used (Tregor, Aston Medical, France) consisting of a Ti-sprayed and HA-coated CoCr shell with a highly polished inner surface articulating with a mobile intermediate polyethylene component. The opening diameter of the mobile insert was 6% smaller than that of the femoral head. In 115 hips, the modular femoral head completely covered the Morse taper, whereas a long-neck option leaved the base of the Morse taper uncovered in the remaining 53 hips.
Introduction
Metal Artefact Reduction Sequence (MARS) MRI is being increasingly used to detect soft tissue inflammatory reactions surrounding metal-on-metal hip replacements. The UK MHRA safety alert announced in April 2010 recommended cross-sectional imaging such as MRI for all patients with painful MOM hips. The terms used to describe the findings include bursae, cystic lesions and solid masses. A recently used term, pseudotumour, incorporates all of these lesions. We aimed to correlate the pattern of abnormalities on MRI with clinical symptoms.
Method
Following our experience with over 160 MARS MRI scans of patients with MOM hips we recognized patterns of lesions according to their: wall thickness, T1/T2 signal, shape, and location. We categorised the 79 lesions from 159 MARS MRI scans of into our novel classification scheme of 1, 2a, 2b and 3. There were two groups of patients: well functioning and painful.
Summary
We report the first use of synchrotron xray spectroscopy to characterize and compare the chemical form and distribution of metals found in tissues surrounding patients with metal-on-metal hip replacements that failed with (Ultima hips) or without (current generation, large diameter hips) corrosion.
Introduction
The commonest clinical category of failure of metal-on-metal (MOM) hip replacements is “unexplained” and commonly involved a soft tissue inflammatory response. The mechanism of failure of the Ultima MOM total hip replacement includes severe corrosion of the metal stem and was severe enough to be removed from clinical use. Corrosion is not a feature that we have found in the currently used MOM bearings. To better understand the biological response to MOM wear debris we hypothesized that tissue from failed hips with implant corrosion contained a different type of metal species when compared to those without corrosion.
The reverse ball and socket shoulder replacement, employing a humeral socket and glenosphere, has revolutionized the treatment of patients with arthritis and rotator cuff insufficiency. The RSP (DjO Surgical, Inc., Austin, Texas) is one such device, characterized by a lateral center of rotation and approved for use in the United States since 2004. Multiple studies by the implant design team have documented excellent outcomes and low revision rates for the RSP, but other published outcomes data are relatively sparse. The objective of this study is to report on the complications and early outcomes in the first consecutive 60 RSPs implanted in 57 patients by a single shoulder replacement surgeon between 2004 and 2010. Forty-four patients were female and mean age at the time of reverse shoulder arthroplasty was 75 years (range 54 to 92 years). The RSP was used as a primary arthroplasty in 42 shoulders and to revise a failed prosthetic shoulder arthroplasty in 18 shoulders. During the study period, 365 shoulder replacements were implanted so that the RSP was used selectively, accounting for only 17% of all shoulder arthroplasties (8.4% for 2004-2007, 24.2% for 2008-2010). Most patients had pseudoparalysis and profound shoulder dysfunction so that mean pre-operative active forward elevation was to 45°, active abduction to 43°, active internal rotation to the buttock, and the mean pre-operative Simple Shoulder Test (SST) score was 1 out of 12. At final follow-up, mean active forward elevation had improved to 101° (p<0.0001), active abduction to 91° (p<0.0001), active internal rotation to the lumbosacral junction (p<0.001), and the mean final SST score was 7 out of 12. There were 16 complications in 14 patients, including 7 reoperations in 6 patients (11%): 3 closed reductions for dislocation, 2 open revisions for instability and for a dissociated liner in the same patient, one evacuation of a hematoma, and one open reduction and internal fixation of a post-operative scapular spine fracture. Two additional scapular spine or acromion fractures and one acromioclavicular joint separation developed postoperatively that impacted outcome adversely but did not require re-operation. None of the glenoid baseplates or humeral stems has been revised and no deep infections have occurred. Experience with reverse shoulder arthroplasty appears to influence the reoperation rate, as 3 of the reoperations occurred following the first 15 reverse shoulder arthroplasties. Overall improvements in active motion and self-assessed shoulder function were comparable to those reported previously. Final active motion results were somewhat lower than those reported previously, which may relate to the selection of predominately pseudoparalytic patients for reverse shoulder arthroplasty in this series. Use of the RSP device for reverse shoulder arthroplasty leads to improved motion and function in carefully selected older patients with pseudoparalysis or a failed shoulder replacement. Re-operations and complications occur but the learning curve may not be as steep as previously reported. This may relate to specific features of the implant system used in this series, as well as to surgeon experience.
Glenohumeral chondrolysis is a devastating condition characterized by the rapid dissolution of glenohumeral cartilage and resultant joint destruction. Excessive intra-articular use of thermal heat, suture anchors that are prominent or loose, and the use of an intra-articular pain pump (IAPP) delivering local anesthetics have all been implicated as causative factors. Between November 2007 and February 2010, 29 patients presented with glenohumeral chondrolysis related to one or more of the causative factors noted above. Seventeen patients have been followed since their initial presentation, with the remainder presenting for evaluation only, at the suggestion of their attorneys. Of those 17 patients, 7 were male and mean age at the time of their index surgery was 28.6 years (range 15-55 years). Two patients developed chondrolysis as a result of prominent suture anchors and 15 as a result of an IAPP delivering bupivacaine. Two patients underwent placement of an IAPP following closed manipulation for adhesive capsulitis and 13 underwent IAPP placement following arthroscopic labrum repair or capsular plication using one to seven suture anchors. Onset of symptoms related to chondrolysis, such as increased pain, stiffness and crepitation, occurred at a mean 8 months (range 1-32 months) following the index procedure. Twelve of the 17 patients underwent one or more additional arthroscopic procedure, typically for debridement and chondroplasty, and in some cases, capsular release. A loose suture anchor was found in one joint at arthroscopy, which was removed. Eleven patients had radiographs documenting joint space obliteration at most recent follow-up or at the time of prosthetic shoulder arthroplasty. At most recent follow-up, 7 patients had undergone 3 total shoulder replacements and 4 humeral head resurfacing procedures. Four other patients were contemplating prosthetic shoulder arthroplasty. For those undergoing shoulder replacement, range of motion recovered modestly so that active forward elevation improved from 111° to 137° (p<0.05) and active abduction improved from 99° to 123° (p<0.05). Seven of the 12 patients presenting for evaluation only had also undergone prosthetic shoulder arthroplasty elsewhere by the time of their presentation, so that overall, 14 of 29 patients had undergone their first prosthetic shoulder replacement for chondrolysis within 25 months (range 9-54 months) of their index procedure. The onset of chondrolysis in two patients following the use of an IAPP after closed manipulation has not been reported previously. Post-arthroscopic glenohumeral chondrolysis (PAGCL) is a devastating condition that strikes young patients and frequently requires shoulder replacement surgery. The use of an intra-articular pain pump delivering local anesthetics is the principal causative factor for glenohumeral chondrolysis in most patients and should be abandoned.
Purpose
To determine the effect of early recovery with 2 different MIS THA for patients with dysplastic hip because of relatively severe muscle weakness before surgery.
Materials & Methods
MIS THA (248 MIS A/L, 96 2-incision) were performed with single surgeon from 2002. Averaged age was 61 years old. Abductor muscle power and VAS score were analyzed preop, 3, 5 7, 14 days, 2, 6 and 12 months after surgery. Patients were prone position and MicroFET machine (HOGGAN Inc. USA) were used for this analysis. All analysis were performed with single observer (physical therapist).
Restoration of joint line in total knee arthroplasty (TKA) is important for kinematics of knee and ligamentous balance. Especially in revision TKA, it may be difficult to identify the joint line. The aim of this study is to define the relationship between epicondyles and articular surface using CT based three-dimensional digital templating sofware $“Athena” (Soft Cube, Osaka, Japan).
137 knees with osteoarthritis, all caces were grade 2 or lower in Kellgren-Lawrence index, were investigated. Perpendicular lines were dropped from the prominences of the medial and lateral femoral epicondyles to the most distal points of articular surfaces and distances of the lines were measured on the axial and coronal planes. The femoral width was measured as the distance between medial and lateral epicondyles. Each of the distance described above was converted to a ratio by dividing by the femoral width.
On the axial plane, the average distance from epicondyles to the posterior articular surfaces were 29.4±2.2mm on the medial side and 21.2±2.3mm on the lateral side. The average of the femoral width was 75.2±4.1mm. On coronal plane, the average distance from epicondyles to the distal articular surfaces were 25.2±2.8mm on the medial side and 21.4±2.5mm on the lateral side.
The ratio for the distance from epicondyles to the distal and posterior joint line compared to femoral width was 0.39±0.02, 0.28±0.03, 0.33±0.03 and 0.28±0.03. The distance from epicondyles to the distal and posterior joint line correlates with the femoral width of the distal femur. This information can be useful in determining appropriate joint line.
The objective of this study is to introduce the forces acting on the knee joint while ascending from kneeling. Our research group has developed a new type of knee prosthesis which is capable of attaining complete deep knee flexion such as a Japanese style sitting,
Ten male and five female healthy subjects participated in the measurement experiment. Although the measurement of subjects' physical parameters was non-invasive and direct, some parameters had to be determined by referring to the literature. The data of ground reaction force and each joint's angle during the motion were collected using a force plate and video recording system respectively. Then the muscle forces and the joints' forces were calculated through our mathematical model. In order to verify the validity of our model approach, we first introduced the data during the activities with small/middle knee flexion such as level walking and rising from a chair; these kinds of data are available in the literature. Then we found our results were in good agreement with the literature data. Next, we introduced the data during the activities with deep knee flexion; double leg ascent [Fig.1 (a)] and single leg ascent [Fig.1 (b)] from kneeling without using the upper limbs.
The statistics of the maximum values on the single knee joint for all the subjects were; during double leg ascent,
Total hip replacements have shown great benefits to patients through relief of pain and restoration of function. However, because of the extensive variation in the size and shape of the femoral canal, especially for the situation encountered in the revision hip arthroplasty, standard uncemented hip systems with a limited number of sizes are unable to provide an accurate fit in every case. This study showed clinical results of 112 primary total hip replacements and 158 revision total hip replacements, using custom made CAD-CAM (Computer Aided Design-Computer Aided Manufactured) hip prostheses inserted between 1992 and 1998.
For primary hip replacements, the implants were designed to produce proximal line-to-line fit with the femoral bone and to provide optimal biomechanical environment of the hip. The stem was HA coated, 53 males and 58 females were included. Mean age was 46.2 years (range 24.6yrs - 62.2 yrs). The average duration of the follow up was 24 years (10 – 17 years). The mean Harris Hip Score (HHS) was improved from 42.4 to 90.3, mean Oxford Hip Score (OHS) was improved from 43.1 to 18.2 and the mean WOMAC hip score was improved from 57.0 to 11.9. There was 1 revision due to failure of the acetabular components but there were no failures of the femoral components. In the whole follow-up period, the survival of the femoral stem alone was 100%.
For revision hip replacements, the implants were designed using our design strategies of graduate approach to different revision situation based on Paprosky's classification of femoral bone defect. The implants were HA coated; some of them had distal cutting flutes. A total of 158 patients (97 males and 61 females) who had operation between 1991 and 1998 were followed up, among them 138 cases were due to aseptic loosening, 6 cases were periprosthetic fractures and 14 cases were infection. The average age was 63.1 years (range 34.6 – 85.9 years). The minimum follow up was 10 years (range 10 – 12 years). The mean Harris Hip Score was improved from 44.2 to 89.3, mean Oxford Hip Score was improved from 41.1 to 18.2 and the mean WOMAC hip score was improved from 52.4 to 12.3 respectively. 6 cases required further revision surgery, among them 3 were due to aseptic implant loosening, the overall survivorship at ten years was 97%.
The CAD-CAM hip stems are able to provide optimal implant fixation and restore hip function for every patient regardless their original femoral shape, bone condition and biomechanics of the hip. The excellent medium to long term clinical results justifies the use of CAD-CAM custom hip stems.
Introduction
Materials and Methods
Five pairs of 50 mm DefCom devices were tested in a ProSim hip wear Simulator for 5 million cycles (MC) at a frequency of 1 Hz. The lubricant was new born calf serum with 0.2% sodium azide diluted with de-ionised water to achieve protein concentration of 20 mg/ml. The flexion/extension was 30° and 15° and the internal/external rotation was 10°. The force was Paul-type stance phase loading with a maximum load of 3 kN and a standard ISO swing phase load of 0.3 kN. Five standard 50 mm BHR devices were tested under the same testing conditions for comparison. Statistical analyses were performed at a 95% confidence level (CL) using the statistics function in Excel (Microsoft(r) Excel 2003).
Introduction
All hip replacements depend upon good orientation and positioning to ensure that implants function well
Aim
To investigate the correlation between edge loading and wear on retrieved implants through linear wear analysis and radiographic examination of implants
Purpose
Many TKA instruments were developed in these days. Distal femoral cutting guide using intra-medullary system were divided into two methods, from anterior or medial. Many companies employed anterior cutting guide, however these guides have a disadvantage of wide skin and quadriceps incision. Only Zimmer provided medial cut guide which performed short skin and quadriceps incision. However, reference point (medial femoral condyle) will be a risk of imprecise cutting for a medial condyle defect cases. We tried L-shaped new distal femoral cutting guide, reference point will be both femoral condyle and cutting from antero-medial side. The purpose of this study was to prove usefulness of the new guide.
Materials and Methods
Twenty-nine knees were employed in this study. All knees were treated with Optetrak knee system (Exactec). Surgical methods were as follows, mid line skin incision, short para-patellar deep incision, no patellar resurfacing, PS type implant and cement fixation were employed. 13 knees were used original anterior cutting guide (O group) and 16 knees were used new antero-medial cut guide (N group). Study items were length of skin incision, length of Quadriceps incision, surgical time, JOA score, and component tilting angles (implant position were compared to femoral axis with AP and lateral view of roentgenograms).
One of the ironies in modern technology for arthroplasty is the stress shielding in cementless stems. The aim of the development of cementless stems had been reduction of stress shielding which cement stems are not free from. In healthy femur, trabecula start form the femoral head and reach at both medial and lateral cortex in rather narrow area around lesser trochanter. So the load from the femoral head is transferred at the level on both medial and lateral side. Cement stems should have binding to the cortical bone from collar to the tip of the stem where the cement interlays, and then the load is transferred gradually from the tip to the collar, which means mild stress shielding. When distal bonding is removed, the load could be transferred as normal femur. This should have been one of the biggest requests for cementless stem. But in realty many cementless stems have difficulty to obtain a load transfer at the level like normal femur.
Since 1990, we have been mainly using lateral flare stems to obtain contact on both medial and lateral side at proximal level. In the present study, different types and length of the designs were compared by 3-Dimensional fill, 3-Dimensional fit and Finite Element Analysis.
Materials and Methods
Stems from DJO: Revelation Standard, Revelation Short, and Linear stems were inserted into patients' canal geometries. Three-D fill and 3-D fit which were reported ISTA2009 and stress transfer were observed by FEA.
Results
The closest fit and fill were observed Revelation Short and Revelation Standard then Linear. The most proximal load transfer was observed Revelation Short, followed by Revelation Standard then Linear.
We have been using 3-dimensional CAD software for preoperative planning as a desktop tool daily. In ordinary cases, proper size stems and cups can be decided without much labor but in our population, many arthritic hip cases have dysplastic condition and they often come to see us for hip replacement after severe defects were created over the acetabulum. It is often the case that has Crowe's type III, IV hips with leg length difference. For those cases preoperative planning using 3D CAD is a very powerful tool.
Although we only have 2-dimensional display with our computer during preoperative planning, 3 dimensional geometries are not so difficult to be understood, because we can turn the objects with the mouse and can observer from different directions. We can also display their sections and can peep inside of the geometries. It is quite natural desire that a surgeon wishes to see the planed geometries as a 3-dimensional materials. For some complicated cases, we had prepared plastic model and observed at the theater for better understanding. When we ask for a model service, each model costs $2,500. We also have small scale desk top rapid processing tool too, however it takes 2 days to make one side of pelvis. Observation of the geometries using 3-dimensional display can be its substitute without much cost and without taking much time. The problem of using 3D display had been the special goggle to mask either eye alternatively.
In the present paper, we have used a 3D display which has micro arrays of powerful prism to deriver different image for each eye without using any goggle.
Method
After preoperative planning, 2 images were prepared for right eye and left eye giving 2-3 degree's parallax. These images were encoded into a special AVI file for 3-dimensional display. To keep fingers away from the device, several scenes were selected and 3-dimensional slide show was endlessly shown during the surgery.
Result
Cup geometries with screws had been prepared and cup position with screws direction were very useful. The edge of acetabulum and cup edge are well compared then could obtain a better cup alignment. Screws are said to be safe if they were inserted in upper posterior quadrant. However so long as the cluster cup was used, when the cup was given 30 degrees anterior rotation, 25 mm screw was still acceptable using CAT angiography.
In previous congress of ISTA in Hawaii, we reported the results about accuracy of the cup center position in our image-free navigation system. In the new version of our navigation system, leg elongation and offset change as well as cup center position can be navigated. In this study, we therefore investigated the accuracy of cup center position, leg elongation and offset change.
Twenty four THA operations were performed with using the image-free OrthoPilot THA3.1 dysplasia navigation system (B. Braun Aesculap, Tuttlingen, Germany) between August 2009 and December 2009 by three experienced surgeons. In this system, cup center height was shown as the distance from tear drop, and cup medialization was shown as horizontal distance from inner wall of acetabulum. Leg elongation and offset change were navigated by comparing the two reference points in femur between registration before neck resection and that after inserting the trial implant. After operation, the cup angles were measured on CT image, and cup center position, leg elongation and offset change were measured on plain radiography. We compared these values that indicated by the navigation system to those measured on the CT image and the plain radiography.
The average cup inclination was 37.5 ± 7.0 degree and anteversion was 22.2 ± 4.7 degree. The average absolute difference between navigation and measured angles were 5.2 ± 4.0 degree in inclination, 5.9 ± 4.0 degree in anteversion. The difference of cup height was 5.8 ± 3.9 mm, cup medialization was 3.8 ± 2.7 mm, leg elongation was 4.3±3.3mm, and offset was 5.4±4.1mm, respectively.
By using this new version navigation system, we can plan the cup center position and navigate it within smaller error of vertical and horizontal direction than the previous system. Moreover, leg elongation and offset change can be satisfactory navigated during operation. However surgeon's skill and learning curve might have influence the accuracy. We have to continue to evaluate this system and make effort to further improvement.
Introduction
There is many reports about complications with a resurfacing total hip arthroplasty (RHA). One of the most common complications is the femoral neck fracture. A notch and malalignment were risk factors for this. For an accurate implanting the femoral component in RHA, we performed 3D template and made a patient specific template (PST) using 3D printer and applied this technique for a clinical usage. We report a preliminary early result using this novel technique.
material and method
We performed 10 RHAs in nine patients (7 male, 2 female) from June 2009 to March 2010 due to osteonecrosis in 7 hips and secondary osteoarthritis in 3hips with a mean age of 48 years (40-60). We obtained a volumetric data from pre-operative CT and planned using 3D CAD software. Firstly, size of femoral components were decided from the size planning of cups. We aimed a femoral component angle as ten degrees valgus to the neck axis in AP and parallel in lateral view avoiding a notch. We measured femoral shaft axis and femoral neck axis in AP and lateral view using 3D processing software. PSTs were made using Laser Sintering by 3D printer which had the heat tolerance for sterilization in order to insert the femoral guide wire correctly. We operated in postero-lateral approach for all the patients PST has the base (contact part) fit to poterior inter trochanteric area. It has the arm reached from the base and sleeve hole to insert the guide pin into the femoral head. We measured the femoral component angle in three dimensions using the 3D processing software postoperatively. We compared the difference of this angle and the pre-operative planed angles. We also investigated the operation time, the volume of bleeding during operation and complications.
There is very limited literature available on the use of prosthetic replacement in the treatment of primary and secondary tumours of the radius. In the past these were treated with vascularised and non-vascularised autografts which had associated donor site morbidity, problems of non union, graft or junctional fractures and delayed return to function. Our study is a mid to long term follow-up of implant survivorship and the functional outcome of metal prosthetic replacement used for primary and metastatic lesions of radius. We had 15 patients (8 males:7 females) with a mean age of 53 years. 8 patients underwent proximal radial replacement, 2 with mid-shaft radial replacement and 6 patients had distal radial replacements with wrist arthrodesis. The indications for replacement included metastatic lesions from renal cell carcinoma, primary giant cell tumours, ewings' sarcoma, chondroblastoma, radio-ulnar synostosis and benign fibrous histiocytoma. The average follow up was 5 years and 6 months (range 3 months - 18 years). Four patients died as a result of dissemination of renal cell carcinoma and two patients were lost to follow-up. There were no complications with the prosthesis or infection. Clinically and radiographically there was no loosening demonstrated at 18 years with secure fixation of implants. Two patients developed interossoeus nerve palsies which partially recovered. Functional outcomes of the elbow were assessed using the Mayo performance score with patients achieving a mean score of 85 postoperatively (range 65-95). All but one patient had full range of motion of the elbow. The patient with radio-ulnar synostosis had a 25 degree fixed flexion pot-operatively. Although the distal radial replacements had decreased range of movements of the wrist due to arthrodesis, they had excellent functional outcomes. Only one patient required revision surgery due to post-traumatic loosening of the implant. Our results of the use of endoprosthetic replacement of radius in the treatment of tumours are encouraging with regards to survivorship of the implant and functional outcome. This type of treatment results in an early return to daily routine activties, good functional outcome and patient satisfaction.
Introduction
Recent gains in knowledge reveal that the ideal acetabular cup position is in a narrower range than previously appreciated and that position is likely different based on femoral component anteversion. For that reason more accurate acetabular cup positioning techniques will be important for contemporary THA. It is well known that malalignment of the acetabular component in THA may result in dislocation, reduced range of motion or accelerated wear. Up to 8% of THA patients have cups malaligned in version by more than ±10° outside of the Lewinnek safe zone. This type of malalignment may result in dislocation of the femoral head and instability of the joint within the first year, requiring reoperation. Reported incidences of reoperation are 1-9% depending on surgical skills and technique. In addition, cup malalignment is becoming increasingly important as adoption of hard on hard bearings increases as the success of large head hard on hard bearings seems to be more sensitive to cup positioning. This study reports the accuracy of a haptic robotic system to ream the acetabulum and impact an acetabular cup compared to manual instrumentation.
Methods
Six fresh frozen cadaveric acetabula were CT scanned and three-dimensional templating of the center of rotation, anteversion and inclination of the cup was determined pre-operatively. Half of the specimens were prepared with manual instrumentation while half were prepared with robotic guidance. Haptic and visual feedback were provided through robotics and an associated navigation system to guide reaming and impaction of the cup. The robot constrained the orientation and position of the instruments thus constraining the inclination, anteversion and center of rotation of the reamer, trial and the final cup. Post-operative CT's were used to determine the achieved cup placement and compared to the pre-operative plans.
The metal-on-metal total hip resurfacing arthroplasty is a good solution for the younger patient with osteoarthritis of the hip. It is effective in pain resolution and provides a good function.
Our study of 300 BHR arthroplasties with a follow-up of 2 to 7 year shows good results in a young and active population.
With an overall survival of 96.7% we obtained similar results to those of the design centre. The overall postoperative HHS score of 95.78 +/− 12.63 is in line with other studies. We noticed a similar increase in HHS in female patients and male patients.
Even in the HOOS scores there was no significant difference between both groups. This is an important finding for the surgeon as well as the patients.
Looking at the VAS scores for satisfaction or reoperation we could state that the high expectations of this population have been fulfilled.
With have an acceptable revision rate of 2.42% the patients undergoing a revision were of a simular mean age than those in the overall group. Five of them are female, two are male. Since there were twice as many female as male patients there is little difference in revision percentage between both groups.
There was 1 patient with a bilateral revision because of ALVAL (aseptic lymphocytic vasculitis associated lesion).
Although femoral neck fractures are a known complication, there where none in our series.
Patients are able to lead an active life and perform sports. The postoperative benefits are equal in men and women. The satisfaction rate confirms that we are able to meet the expectations in this high demand group.
Introduction
Hip resurfacing arthroplasty has gained popularity as an alternative for total hip arthroplasty. Usually, cemented fixation is used for the femoral component. However, each type of resurfacing design has its own recommended cementing technique.
In a recent investigation the effect of various cementing techniques on cement mantle properties was studied. This study showed distinct differences in cement mantle volume, filling index and morphology.
In this study, we investigated the effect of these cement mantle variations on the heat generation during polymerization, and its consequences in terms of thermal bone necrosis.
Materials and methods
Two FEA models of resurfacing reconstructions were created based on CT-data of
Thermal analyses were performed of the polymerization process, simulating three different types of bone cement: Simplex P (Stryker), CMW3 (DePuy J&J) and Osteobond (Zimmer), with distinct differences in polymerization characteristics. The polymerization kinematics were based on data reported previously.
During the polymerization simulations the cement and bone temperature were monitored. Based on the local temperature and time of exposure, the occurrence of thermal bone necrosis was predicted. The total volume of necrotic bone was calculated for each case.
Introduction
Proper alignment of the components and soft tissue balance are the two factors that determine the long term outcome of total knee arthroplasty (TKA). On the femoral side a distal cut made perpendicular to the MA will restore the MA of the leg. Different methods are commonly used to resect the femur perpendicular to its MA. In uncomplicated cases, most surgeons routinely use a fixed valgus cut angle (VCA) of 5° or 6°. Various studies have questioned the use of fixed valgus angle resection to restore the mechanical axis. The purpose of this prospective study is to analyze the variability in the valgus angle following computer assisted TKA.
Materials and methods
Twenty-three patients who underwent computer assisted TKA in our institution in 2009 were involved in the study. A total of 40 knees were available for analysis. All the knees underwent a CT scanogram postoperatively. Each scanogram was analyzed using the Amrita medvision(r) software. The angle subtended between the mechanical axis and the distal femoral anatomic axis is the valgus angle. Two independent observers calculated all the values and the interobserver reliability was calculated.
Introduction
Hip implant research has been carried out for decades using hip simulators to reflect situations
Materials & Methods
Three pairs of 50mm as cast (AC) and four pairs of 50mm double heat treated (DHT) CoCr MoM devices were tested in a ProSim hip simulator. In order to determine the frequency for testing, Patients' activities have been monitored using a Step Activity Monitor (SAM) device. The data showed a relatively slower walking pace (frequency) than that used in the hip simulator studies. The new frequency, along with stop/start motion and various kinetics and kinematics profiles have been used in putting together a more physiologically relevant hip simulator test protocol. The lubricant used in this study was new born calf serum with 0.2 % (w/v) sodium azide concentration diluted with de-ionised water to achieve an average protein concentration of 20 g/l. Gravimetric measurements have been taken at 0.5, 1, 1.5 & 2 million cycle (Mc) stages and ion analysis has been carried out on the serum samples.
Kneeling is one of important motion in Asians culture, also there were teachers of tea or flower ceremony who sit seiza routinely. But also, people in the Middle East need deep flexion keeling when they pray. At the symposium with the title of “A Challenge of deep flexion after TKA”, held at the 33rd Annual Meeting of Japanese Society of Reconstructive Arthroplasty in 2003, it was agreed that the definition of post-operative deep flexion to be more than 130 degrees of flexion. Four hundred and seventy two patients treated with a
Introduction
There is no criteria to select cruciate retaining (CR) or posterior substitute (PS) component in total knee arthroplasty (TKA). In this study, extension and flexion gaps were measured intra-operatively with posterior cruciate ligament (PCL) remained to reveal characteristics of the gaps. Component type selection, CR or PS, was decided intra-operatively according to the gaps in each knee.
Materials and methods
One hundred and sixty knees with osteoarthritis were investigated. Extension gap (EG) was made by resection of 8 mm distal femur and 10 mm proximal tibia. After measurement of femoral AP size, about 4 mm bigger 4-in-1 femoral cutting guide than measured size was used for pre-cut of femoral posterior condyle[Figure 1]. With this technique, flexion gap (FG) was made 4 mm smaller than usual measured resection. The gaps were measured by a tension device with 30 pounds tension and FG was corrected by the amount of pre-cut. According to the EG and corrected FG, component type was decided. Too small FG usually needed PCL resection or (and) smaller size of femoral component to make enough final FG. On the other hand, large FG needed careful consideration to sacrifice PCL for adequate final FG. In these cases, CR component was selected usually. If necessary, soft tissue was released for good ligament balance. As the final step of the surgical procedure, the size of femoral component was decided for adequate final FG. It was changeable up to 4 mm larger than measured size[Figure 2].
Background
Mobile-bearing (MB) total knee prostheses have been developed to achieve lower contact stress and higher conformity compared to fixed-bearing total knee prostheses. However, little is known about the in vivo kinematics of MB prostheses especially the motion of the polyethylene insert (PE) during various daily performances. And the in vivo motion of the PE during stairs up and down has not been clarified. The objective of this study is to clarify the in vivo motion of MB total knee arthroplasty including the PE during stairs up and down.
Patients and methods
We investigated the in vivo knee kinematics of 11 knees (10 patients) implanted with PFC-Sigma RP-F (DePuy). Under fluoroscopic surveillance, each patient did stairs up and down motion. And motion between each component was analyzed using two- to three-dimensional registration technique, which used computer-assisted design (CAD) models to reproduce the spatial position of the femoral, tibial components, and PE (implanted with four tantalum beads intra-operatively) from single-view fluoroscopic images. We evaluated the range of motion between the femoral and tibial components during being grounded, axial rotation between the femoral component and PE, the femoral and tibial component, and the PE and tibial component during being grounded.
Background
Currently there are various knee prosthesis designs available each with its plus and minus points; there is no general consensus on whether mobile-bearing knees are functionally better than fixed-bearing ones. This study is designed to compare outcomes after total knee arthroplasty with both of the above prostheses.
Materials & Methods
50 patients (68 knees) who'd had a total knee arthroplasty between April 1999 and April 2008 at both Akhtar and Kian Hospitals for primary osteoarthritis were selected. In 30 cases a fixed-bearing knee (Scorpio(r), Stryker) and in the remaining 38 a mobile-bearing prosthesis (Rotaglide(r), Corin Group) was used. Patients' knees were scored before and after the operation according to the Knee Society Scoring System. The mobile-bearing group had an average age of 65 and 34 months' follow-up; in the fixed-bearing group the average age was 69 and the average follow-up 30 months.
Introduction
Metal on metal hip bearings (MoM) are under scrutiny. Short and mid-term complications attributed to metal wear debris have been reported. Distinctions between MoM prostheses exist. Thus, generalizing findings from one design to another is questionable. This study reports minimum 5 yr. Pinnacle™ modular MoM results.
Methods
Between September 2001 and October 2004, 95 consecutive MoM THAs were performed by one surgeon in a prospective cohort design. Mean age was 53 yrs (range 34-70); 57 were male. Mean BMI was 29 (range 20-46). OA was noted in 87 patients. Head size was 28mm in 3 and 36mm in 92. Surgical approach was postero-lateral in all patients. Harris Hip Score (HHS), WOMAC, ROM and radiographs were evaluated preoperatively, at 6-months, and yearly thereafter.
Introduction
Several options exist for the treatment of periprosthetic osteolysis in revision knee surgery. We describe our preliminary short-term experiences using trabecular metal (TM) technology in order to fill bony defects either on the femoral or on the tibial side.
Material and Methods
52 revision knee surgeries in which this TM technology had been used were retrospectively reviewed clinically and radiographically. Indication for revision included 51 cases with aseptic loosening of Total Knee Arthroplasty. In one case of periprostheti infection, a staged revision procedure was performed. Assessment of bone loss included the AORI classification (1989) and was performed pre- and intraoperatively. Clinical evaluation was performed using the HSS score. In 6 cases in addition to usng the TM cones, an impaction grafting technique was performed.
Introduction
There have been concerns regarding the quality of training received by Orthopaedic trainees. There has been a reduction in working hours according to the European working times directive. National targets to reduce surgical waiting lists has increased the workload of consultants, further reducing the trainees' surgical experience. Navigation assisted procedures are successfully used in orthopaedics and provides useful feedback to the surgeon regarding precision of implant placement. We investigated the use of navigation aids as an alternative source of training surgical trainees.
Methods
We choose a navigation assisted knee replacement (TKR) model for this study. A first year Orthopaedic registrar level trainee was taught the TKR procedure by a scrubbed consultant in 5 cases. He was then trained in use of non-CT based navigation surgery. The Trainee then performed navigation assisted non-complex primary TKR surgery. A consultant Orthopaedic surgeon was available throughout for advice and support. Data collected included pre and post procedure valgus and varus alignment of the knee, total operative time and WOMAC scores pre and post operatively.
Introduction
In recent years, there has been a significant advancement in our understanding of femoro-acetabular impingement and associated labral and chondral pathology. Surgeons worldwide have demonstrated the successful treatment of these lesions via arthroscopic and open techniques. The aim of this study is to validate a simple and reproducible classification system for acetabular chondral lesions.
Methods
In our classification system, the acetabulum is first divided into 6 zones as described by Ilizalithurri VM et al [Arthroscopy 24(5) 534-539]. The cartilage is then graded as 0 to 4 as follows: Grade 0 – normal articular cartilage lesions; Grade 1 softening or wave sign; Grade 2 - cleavage lesion; Grade 3 - delamination and Grade 4 –exposed bone. The site of the lesion is further typed as A, B or C based on whether the lesion is 1/3 distance from acetabular rim to cotyloid fossa, 1/3 to 2/3 distance from acetabular rim to cotyloid fossa and > 2/3 distance from acetabular rim to cotyloid fossa.
For validating the classification system, six surgeons reviewed 14 hip arthroscopy video clips. All surgeons were provided with written explanation of our classification system. Each surgeon then individually graded the cartilage lesion. A single observer then compared results for observer variability using kappa statistics.
Introduction
Infection following total joint arthroplasty is a major and devastating complication. After removal of the initial prosthesis, an antibiotic-impregnated cement spacer is inserted for approx. three months. Treatment is completed by a second stage revision arthroplasty.
Up to now, spacers are produced from conventional bone cements that contain abrasive radio-opaque substances like zirconium dioxide or barium sulphate. As long as spacer wear products (cement particles containing these hard substances) are not fully removed during the final revision surgery they may enter the articulating surfaces of the revision implant leading to third body wear.
In order to reduce the formation of reactive wear particles, a special cement (Copal(r) spacem) without abrasive zirconium dioxide or barium sulphate was developed.
To date, no comparative tribological data for cement spacers have been published. Hence, we carried out a study on the wear properties of Copal(r) spacem (with and without gentamicin) in comparison to conventional bone cements (Palacos(r) R and SmartSet(r) GHV).
Material and Methods
In order to assure reproducible forms of the femoral and tibial components, silicon rubber moulds were produced and filled with the respective cement. Force-controlled simulation was carried out on an AMTI knee simulator (Figure I). The test parameters were in accordance to ISO 14243-1 with a 50% reduced axial force (partial weight bearing). Tests were carried out at 37 °C in closed chambers filled with circulating calf serum. Tests were run for 240,000 cycles (representing the average step rate during 6-8 weeks) at a frequency of 1 Hz. For wear analysis, digital photographs of the spacer were taken at the beginning and at the end of the testing period. The areas of wear scars were measured by the means of a digital image processing software.
Introduction
Osteolysis and aseptic loosening in total hip replacement (THR) is often associated with polyethylene (PE) wear. This caused interest in alternative bearing surfaces. Since the mid nineties, research focused on hard-hard bearings like metal-on-metal (MOM) or ceramic-on-ceramic (COC). However, concerns remain about biological reactions to metallic wear debris or failure of the ceramic components. A new approach to reduce wear with a minimized risk of failure may be the use of a metallic cup in combination with a ceramic head, the so called ceramic-on-metal bearing (COM). The aim of this study was to estimate the wear behaviour at an early stage of this COM bearing type in comparison to COC bearings using a hip simulator.
Material and Methods
Simulator studies were carried out on a single station hip simulator (MTS 858 Mini Bionix II, Eden Prairie, USA) in accordance to ISO 14242-1. Bovine serum was used as the test medium. Four COM and four COC bearings were used, both 36mm in diameter. The heads were made of a mixed-oxid ceramic (Biolox Delta(r)) paired with a high carbon wrought CoCrMo cup in the COM group whereas both components were made of Biolox Delta(r) in the COC group. Simulation was run to a total of 2.4×106 cycles. Wear measurements were performed in intervals of 0.2x106 cycles using a gravimetric method (Sartorius Genius ME235S, measuring solution: 15 μg, Sartorius, Göttingen, Germany).
Introduction
The incorporation of computer navigation in total hip arthroplasty (THA) has been much slower then for total knee arthroplasty (TKA). Computer navigation has proven itself in the realm of TKA but still has yet to advance in THA. The reasons for this include the lack of ease of incorporation, accuracy and precision, and the addition of overall operative time. Another reason for this lack of progress is that a majority of THA's are done with the patient in the lateral position through a posterior or lateral approach making the tracker placement and the registration process somewhat cumbersome. In the direct anterior approach the patient is in the supine position, which accommodates pelvic tracker placement and significantly facilitates the registration process. At our institution we use the direct anterior approach and computer navigation on all of our primary THA's. We hypothesized that computer navigation facilitates cup placement and leg length determination with out significantly increasing our operative time.
Materials and Methods
This was a prospective study comparing a consecutive series of 150 computer navigated total hips to a consecutive series of 150 none navigated total hips. The two groups were similar by age, sex, and BMI. Operative times were collected using our secure online database. The start and stop of operative time was incision to final reduction respectively. Post operative radiographs were analyzed using TraumaCad 2.0 (Voyant Health, Columbia, MD). Cup angle and leg length were measured on A/P pelvic views. Simple descriptive statistics and t-tests were used to analyze data.
Introduction
Total knee arthroplasty is traditionally performed using bone anatomy to dictate femoral implant rotation and soft tissue release to balance any resulting deficiencies. A force sensing device has been developed that reverses this conventional order. It measures the forces in the medial and lateral compartments and dictates the femoral rotation cuts when these are equal. The purpose of this study was to compare the traditional methods of femoral rotation (TEA, AP axis, and posterior referenced) to this novel approach using computer navigation with the force sensor to determine a balanced flexion gap.
Methods
This was a prospective cohort study of 50 consecutive primary TKA's. Inclusion criteria were diagnosis of OA and primary TKA. Exclusion criteria were inability to use force sensing device. The cohort consisted of 29 females and 19 males with an average age of 70.8 years (50.2-90.3) and BMI of 32.0 (19.8 – 56.1). Intra-operative data was collected using computer navigation. Post operative CT scans were obtained on 31 of the 50 knees to assess femoral implant rotation to the patients' true TEA. CT measurements were made by two different observers. Simple descriptive statistics and t-tests were used for analysis.
Introduction
Accurate soft tissue balancing has been recognized as important as alignment of bony cut in total knee arthroplasty (TKA). In addition, using a tensor for TKA that is designed to facilitate soft tissue balance measurements throughout the range of motion with a reduced patello-femoral (PF) joint and femoral component in place, PF joint condition (everted or reduced) has been proved to have a significant effect for intra-operative soft tissue balance. On the other hand, effect of patellar height on intra-operative soft tissue balance has not been well addressed. Therefore, in the present study, we investigated the effect of patellar height by comparing intra-operative soft tissue balance of patella higher subjects (Insall-Salvati index>1) and patella lower subjects (Insall-Salvati indexâ‰/1).
Materials and methods
The subjects were 30 consecutive patients (2 men, 28 women), who underwent primary PS TKA (NexGen LPS-flex PS: Zimmer, Warsaw, IN, USA) between May 2003 and December 2006. All cases were osteoarthritis with varus deformity. Preoperative Insall-Salvati index (ISI) was measured and patients were divided into two groups; the patella higher group (ISIï1/4ž1: 18 knees average ISI was 1.12) and the patella lower group (ISIâ‰/1; 12 knees average ISI was 0.94). Component gap and ligament balance (varus angle) were measured using offset-type tensor with 40lb distraction force after osteotomy with the PF joint reduced and femoral trial in place at 0, 10, 45, 90, 135 degrees of knee flexion. Data of two groups were compared using unpaired t test.
We report long term outcomes of the Rotaglide mobile bearing total knee arthroplasty (RTK).
Method
Between 1995 and 1998, 61 RTK prostheses were implanted at our institution consecutively. Of 34 knees with a median duration to end of follow up of 13.0 years (range 11.4 to 14.2 years), the clinical result using Knee Society Score and radiological analysis using Knee Society Roentgenographic Sytstem was evaluated.
Result
The prosthesis had an estimated survival probability of 94.1% at 13 years. There was one case of deep infection and one case of meniscal component failure.
Background
Mobile-bearing (MB) total knee prostheses have been developed to achieve lower contact stress and higher conformity compared to fixed-bearing total knee prostheses. However, little is known about the in vivo kinematics of MB prostheses especially about the kinematics of polyethylene insert (PE). In vivo motion of PE during squatting still remains unclear. The objective of this study is to investigate the in vivo motion of MB total knee arthroplasty including PE during squatting.
Patients and methods
We investigated the in vivo knee kinematics of 11 knees (10 patients) implanted with Vanguard Rotationg Platform High Flex (Biomet(r)). Under fluoroscopic surveillance, each patient did a wight-bearing deep knee bending motion. Motion between each component was analyzed using two- to three-dimensional registration technique, which uses computer-assisted design (CAD) models to reproduce the spatial position of the femoral, tibial components, and PE (implanted with five tantalum beads intra-operatively) from single-view fluoroscopic images. We evaluated the range of motion between the femoral and tibial components, axial rotation between the femoral component and PE, the femoral and tibial component, and the PE and tibial component, and AP translation of the nearest point between the femoral and tibial component and between the femoral component and PE.
Introduction
While the use of stemmed implants is accepted for patients with medial ligament laxity in primary total knee arthroplasty (TKA), the role of stemmed implants in the setting of isolated lateral laxity is unclear. We present a cohort study to assess the effect of unstemmed, constrained TKA for isolated lateral laxity.
Methods
1745 primary TKA performed by the senior surgeon were reviewed. 39 knees in 33 patients with isolated lateral laxity managed with unstemmed components were compared to matched stemmed controls (37 knees in 28 patients). Lateral instability was defined intra-operatively based on >7mm gap in mid-flexion/full extension/figure-of-four with well-positioned components. Primary outcome measures were clinical failure for aseptic loosening (with need for revision as the endpoint) and any radiographic signs of loosening.
Backgrounds
The authors present an analysis of 30 cases of total hip prosthesis performed with minimally invasive surgical earlier compares with 30 cases of total hip prosthesis performed surgically with direct side. The intent is to demonstrate the immediate and clear advantages especially in the postoperative surgical minimally invasive front.
Methods
The authors present a randomized study of thirty cases of patients undergoing surgery for osteoarthritis of the hip prosthesis with primary surgical minimally invasive front compared to a group of 30 patients undergoing surgery with direct surgical side. All patients had the same cementless implants and instruments with the same surgeon. Patients were then evaluated in four different times: before surgery, immediate postoperative, after 1 week and 4 months after surgery.
Introduction
Wear performances and fracture toughness of the alumina-matrix composite (AMC) Biolox-delta(r) are pointed out in the literature. This study is a prospective monocentric evaluation of 32 and 36 mm AMC/AMC bearing surfaces.
Material and methods
141 THA were included prospectively since 2006 in 127 patients. (62 females, 65 males, mean age 62, 2 years, mean BMI 25, 5). 134 cases were primary implantations. Mean follow-up is 40.9 months (29.8-53.4). In all patients we used the same cementless stem and cup.
Clinical and radiological data were evaluated with a special attention for ceramic fracture and squeaking.
Introduction
The ceramic-on-ceramic strategy in acetabular revision faces potential limitations due to the femoral stem, as the implantation of ceramic ball head on a previously used taper is not recommended. Delta (r) ball heads with titanium sleeves have been proposed to avoid femoral revision. The study reports a minimum 3 years follow-up experience using this strategy.
Materials and Methods
This series report 42 revisions (16 metal-on-metal and 26 PE THA) in 39 patients (mean age 59.2 years, mean BMI 25). The 12-14, 5°46 sleeves were used in 24 cases and 10-12, 6° in 18 cases. (32mm ball head in 26 cases and 36 mm in 16 cases). Titanium serum level has been studied to detect the potential release from the sleeve-taper interface.
Purpose
The purpose of this study was to evaluate the complications related to the prosthesis design in patients managed with cemented total knee arthroplasty (TKA) with the anterior-posterior glide (APG) mobile bearing prosthesis.
Materials and Methods
One hundred eighty three total knee arthroplasties were performed using APG Low Contact Stress mobile bearing prosthesis (Depuy, Warsaw, IN) on 146 patients with an average of 8.4 years follow-up (range, 7 to 10 years). Patients were evaluated clinically and radiologically according to the American Knee Society clinical scoring system. The anteroposterior translation, anterior soft tissue impingements, and complications were assessed at the follow-up periods.
The modern generation of hip resurfacing arthroplasties was developed in the early 1990's with one of the original designs being the McMinn Resurfacing Total Hip System. This was a hybrid metal on metal prosthesis, with a smooth hydroxyapetite coated press fit mono block cobalt chrome shell with a cemented femoral component. Although no longer produced in this form, lessons may be learned from this original series of components. With metal on metal resurfacing arthroplasty now facing criticisms and concerns with regard function, bone preservation capability and soft tissue issues such as ‘pseudotumors’, it is the aim of this long-term study to assess the outcome and survival of an original series of resurfacing arthroplasties.
27 resurfacing arthroplasties were performed in 25 consecutive patients between June 1994 and November 1996. 16 right hips and 11 left were performed in 14 female patients and 11 male patients. The average age at the time of surgery was 50.5 years (SD 7.9, range 30-63). All surgeries were performed by a single surgeon using a posterior lateral approach. Following the initial early care, each patient received bi-annual follow up along with open access to the clinic with any concerns or complications. A retrospective review of the case notes was conducted and outcome scores retrieved from a prospectively updated database. Radiographs were analyzed and a Kaplan Meier survival chart was constructed for the group.
At latest review 3 patients have died (5yrs, 8yrs and 13.8yrs) and 1 patient has been lost to follow up (5yrs). 7 resurfacings have required revision, all due to acetabular loosening, at a mean follow up of 7 years 11months (SD 2.03years, range 4-10). Metallosis was documented in 4 of the revision cases, however no extensive soft tissue inflammation or ‘pseudotumor’ identified. The mean follow up of the remaining 16 hips is 12years and 10months (SD 12.8months, Range 10.4yrs-14.0 years). The Kaplan Meier survival at a minimum follow up of 10 years is 75.8% (95% CI 0.67-0.95). Mean Oxford hip scores at latest follow up was 20.6 (SD 8.8, range 12-38). There was no significant difference between cup inclination angles for the surviving cohort and those who required a revision procedure with mean cup inclinations of 52.5 (SD 5.5, range 45-60) and 58 degrees respectively (SD 9.1, range 50-70)(p=0.255).
This original series of hip resurfacings, with up to 14 years follow up, shows a survival of 76% at the minimum follow up of 10 years. All failures were due to loosening of the smooth backed acetabulum, which with a modern porous coating, failure may have been avoided or delayed. Despite high inclinations angles no soft tissue reactions were identified within this series. No femoral failures were identified suggesting unlike much literature focus, long-term failure may not be related to the femoral head or neck.
The emerging of non-fusion surgery is aimed to solve the long-term complication of fusion surgery that may bring the adjacent disc degeneration. Among several kinds of artificial discs developed in these years, the majority in the market is Prodisc-L (Synthes Inc.) which is designed with the purpose to restore the motions including anteroposterior translation, lateral bending, and axial rotation. These is also one artificial disc called Physio-L (Nexgen Spine) which were hyper-elastic material (Polycarbonate Polyurethanes) and is designed to restore the motions maintioned above plus axial loading. The concept of using hyper-elastic material as disc is to mimic the material properties of intervetebral discs so that this disc both absorb the axial loading and also restore the physiological range of motion. Few studies focused on the biomechanical behavior of hyper-elastic artificial discs have yet been reported. Therefore, the purpose of this study is to compare the biomechanical behavior between Prodisc-L and Physio-L.
A validated three-dimensional finite element model of the L1-L5 lumbar intact spine was used in this study with ANSYS software [Fig.1]. Total disc replacement surgery, partial discectomy, total nuclectomy and removal of the anterior longitudinal ligament were performed at the L3/L4 segment of this intact model, and the Prodisc-L and Physio-L was implanted into L3/L4 segment, respectively. In addition, hyper-elastic materials adopted by Physio-L are usually categorized by their hardness into soft and hard [Fig.2]. Therefore, two kinds of Physio-L were studied. A 400 N follower load and a 10 N-m moment were applied to the intact model to obtain four physiological motions as comparison baseline. The implanted models were subjected to 400 N follower load and specific moments in accordance with the hybrid test method.
For the Prodisc-L model in the surgical segment, the range of motion (ROM) varied by -26%, +17%, -0.01%, and -0.04% in flexion, extension, lateral bending, and axial rotation, respectively, as compared to intact model [Fig.3]. For the Physio-L (soft) model, ROM varied by +10%, +8%, +3%, and +19% in four physiological motions, respectively. For the physio-L (hard) model, ROM varied by +1%, +8%, +1%, and +11% in four physiological motions, respectively. For the Prodisc-L model in the adjacent segments, ROM varied by +4% ∼ +10%, -2% ∼ -5%, -1% ∼ -4%, and +1% ∼ -2% in four physiological motions, respectively. For the Physio-L (soft) model, ROM varied by 0% ∼ -5%, -2% ∼ -5%, -0% ∼ -5%, and -9% ∼ -11% in four physiological motions, respectively. For the physio-L (hard) model, ROM varied by +4% ∼ -2%, +8% ∼ -5%, +1 ∼ -5%, and +11% ∼ -6% in four physiological motions, respectively.
As seemed in the simulation, the behavior of Physio-L (both soft and hard) is similar to that of intact model under flexion and extension, but not in axial rotation. In addition, Physio-L (hard) model is more similar to intact model as compared to Physio-L (soft) model.
Polymethyl methacrylate spacers are commonly used during staged revision knee arthroplasty for infection. In cases with extensive bone loss and ligament instability, such spacers may not preserve limb length, joint stability and motion.
We report a retrospective case series of 19 consecutive patients using a custom-made cobalt chrome hinged spacer with antibiotic-loaded cement. The “SMILES spacer” was used at first-stage revision knee arthroplasty for chronic infection associated with a significant bone loss due to failed revision total knee replacement in 11 patients (58%), tumour endoprosthesis in four patients (21%), primary knee replacement in two patients (11%) and infected metalwork following fracture or osteotomy in a further two patients (11%). Mean follow-up was 38 months (range 24–70). In 12 (63%) patients, infection was eradicated, three patients (16%) had persistent infection and four (21%) developed further infection after initially successful second-stage surgery. Above knee amputation for persistent infection was performed in two patients.
In this particularly difficult to treat population, the SMILES spacer two-stage technique has demonstrated encouraging results and presents an attractive alternative to arthrodesis or amputation.
Suction drains provide an easy and feasible method for controlling hemorrhage after total knee arthroplasty. However, there has been no compromise regarding the optimal clamping time for these drains. We conducted a randomized clinical trial to compare 12-hour drain clamping and continuous drainage after total knee arthroplasty in terms of wound complications, blood loss and articular range of motion. In order to eliminate any other factor except duration of clamping, we chose to compare knees belonging to one single person, as well as restricting the study to those knees undergoing surgery due to osteoarthritis. From a total of 100 knees (50 patients) studied, the 12-hour clamping method resulted in a significantly smaller amount of post-operative blood loss (p<0.001). The passive ranges of motion and wound complications were not significantly different between the two groups.
Background
The role of different surgical approaches and types of implant (1-17), surgical technique (9, 10, 21-24), patient's age (6, 8, 31), activity level (5), weight (17) and other demographic factors have been investigated in a lot of studies. The aim of this study is to assess the effect of demographic factors as well as the effect of traditional life-style in patients who had total hip arthroplasty (THA) in our centre within the past 20 years.
Materials and Methods
We reviewed the average Harris Hip Score (HHS) and the prosthesis survival in 210 patients including 235 THAs and 49 revisions between 1985 - 2005. The mean F/U was 6.1 years and average HHS was 78.08±15.7. 26 patients were dead and 17 were inaccessible. The effects of traditional life-style and daily activity level on implant loosening were also considered.
Background
There is paucity of data concerning the morphological dimensions of the distal part of the femur and the proximal part of the tibia in Indian population. The objective of this study was to analyse the exact anatomic data collected from patients undergoing total knee arthroplasty.
Methods
Morphologic data from the distal part of the femur and proximal part of the tibia, from 50 knees, were obtained during total knee Arthroplasty, with a microcalliper. The study included 30 women and 20 men, who had a mean age of 65 years. A characterisation of the aspect ratio (the medial-lateral to anterior-posterior dimensions) was made for the proximal aspect of the tibia and distal part of the femur.
It is widely accepted that navigation system for TKA improves precision in component alignment. Furthermore, some of the system can measure knee kinematics during surgery. On the other hand, the measurements of kinematics during surgery have limitations because of anesthesia and usage of air tourniquet. The purpose of the present study is to compare the knee kinematics during surgery using navigation system and that after surgery using 2D/3D Registration Technique. Our final goal of the study is to improve clinical outcome by performing feedback of good clinical results to operating theater by means of kinematic analysis.
Kinematics of ten TKA knees for female (average age 71 years old) medial compartmental osteoarthritic knees concerning axial rotation and anterior-posterior translation were measured twice, the time during surgery and 4 weeks after surgery. During surgery, measurement was performed using CT based navigation system (Vector Vision 1.6, Brain LAB, Heimstetten, Germany). Four weeks after surgery, knee kinematics was measured again using a 2-dimensional to 3-dimensional registration technique, which used computer-assisted design models to reproduce the position of metallic implants from single-view fluoroscopic images. Surgery was performed by single surgeon using subvastus approach to eliminate the influence of approach to muscle balance. Implant using the present study was P.F.C. Sigma RP-F (DePuy, Warsaw, USA).
Axial rotation in navigation and 2D/3D are 12.3+/−2.3, and 12.6+/−3.8, respectively. Axial rotations in both of the measurement have the same pattern. A-P translations also have the same pattern between measurement in navigation and that in 2D/3D technique. These results suggested that intraoperative kinematic measurement links to postoperative kinematics. Studies of correlations between kinematics and good clinical results are ongoing.
INTRODUCTION
The number of patients undergoing total hip replacement surgery is rising and thus the number of periprosthetic fractures is set to increase. The risk factors for periprosthetic fractures include osteolysis, rheumatoid arthritis, osteoporosis and use of certain types of implants. Evidence from literature suggests that the mortality rate within one year is similar to that following treatment for hip fractures thus as surgeons it is important for us to understand the various management strategies of these fractures.
MANAGEMENT
Acetabular periprosthetic fractures are uncommon and classified into Type I, in which the acetabular component is radiographically stable and Type II, in which the acetabular component is unstable. It is better to prevent than to treat these fractures.
Femoral periprosthetic fractures have several classifications the most commonly used is the Vancouver classification (fig 1).
Type-A fractures are proximal and can involve the greater or lesser trochanter. These are often related to osteolytic wear debris and therefore revision of the bearing surface with bone grafting is recommended. AG involves the greater trochanter and AL involves the lesser, and these can usually be stabilised by cerclage wires supplemented by screws or plates if required (fig 2).
Management of type B fractures is more controversial and will be discussed in depth with reference to all recent papers at the meeting and data from the Swedish Joint Registry. In summary the management is shown in fig 3.
In type-C fractures, one should ensure the fixation device bypasses the femoral stem by at least 2 diaphyseal diameters. Management is as shown in fig 4.
18 Patients with SCD and 2ndry Osteoarthritis of their hips due to Avascular Necrosis underwent uncemented THA.
There were 12 male and 6 female patients.
Patient had their pre op WOMAC/SF-36/HOOS/and Oxford hip scores recorded preoperatively a well as 3 month, 6months and one year post op.
The outcome scores at one year were significantly better than the pre operative scores
However, when compared to a matched cohort of patients who underwent THA for reasons other than SCD/AVN, e.g. primary OA, rheumatoid arthritis, post traumatic OA, the WOMAC pain score improvement was less.
In this study patients were randomized between surgeon chosen pressure (control) and an automatically determined tourniquet pressure(study group). Of 112 patients in the study group, 5% failed to obtain an automatic pressure. Of the remainder, the average tourniquet pressure was 198 +/− 20.2 mm Hg compared to 259.6 +/− 4.4 mmHg for the control group (p<0.0001). Of the study group 94 (88.6%) had good to excellent fields compared to the control group where 100 (77.5%) had good to excellent fields (p<0.05). The automatic measurement of limb occlusion pressure results in better operative fields at a lower pressure.
BACKGROUND
Acetabular defects are encountered in both primary total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH) and in revision THA. The purpose of this study was to evaluate the clinical and radiographic results of one method of acetabular reconstruction for THA using a hydroxyapatite (HA) block with either an autogenous graft or allograft of impacted morsellized bone in conjunction with a cemented socket.
METHODS
Fourteen hips in 14 patients (all female; average age, 64 years) were treated with the above technique in primary (11 DDH) or revision THA (three loosened sockets). All patients were followed clinically in a prospective fashion, and radiographs were analyzed retrospectively. One initial patient had 16-year follow-up, whereas the remaining 13 patients had follow-up between four and 5.5 years.
Internal fixation for supracondylar fracture of the femur after total knee arthroplasty (TKA) is technically difficult and troublesome because the distal bony fragment is often osteoporotic and too small to fix by screws or K-wires. In addition, the femoral component interferes with the screws or K-wires to be inserted from distal direction for fixation of the fracture.
Patients and Methods
Four knees in 4 patients (all female; average age, 81.5 +/− 2.6 years) with the fracture after TKA were treated with revision TKA. Follow-up period was between six months and 3 years postoperatively
Operative technique
All operations were performed with the patient in the supine position and using a curved anterior (Payer) approach with or without osteotomy of the tuberositas tibiae. The femoral component was removed with detachment from fractured bony fragments. New femoral component with long stem for fixation of the fracture were inserted with bone cement in each case.
Nowadays many new minimally invasive techniques are experienced to perform lower lumbar interbody fusion in attempt to decrease the complications related to open anterior approach. AxiaLIF (axial lumbar interbody fusion) system is a percutaneous transacral approach that exploits the virtual presacral retroperitoneal space to perform annulus-sparing discectomy and interbody instrumented fusion of lower lumbar disc spaces. Additioning posterior percutaneous instrumentation, a robust axial construct is placed which restores disc height, sagittal balance and lordosis with minimal muscle dissection, blood loss and postoperative pain.
Via fluoroscopically-guided approach, AxiaLIF procedure creates a presacral retroperitoneal corridor in the midline through a paracoccigeal skin incision of 2-3 cm. This space is void of neuro-vascular major elements. A safe working cannula is put in and docked in the S1-S1 entry level and a transacral channel is realized gaining the central space of the disc. A 360° annulus-sparing radial discectomy is performed with special cutters even in case of collapsed disc space and the bone graft is inserted. The following screwing of AxiaLIF rod restores disc height via distraction if necessary, decompresses the neural foramen indirectly and undertakes instantaneous rigid fixation of adjacent vertebral bodies. Using the same incision point and trajectory through the presacral space as AxiaLIF, it is possible to realized a similar procedure L4-S1 vertebral fusions called AxiaLIF 2L.
Between february 2009 and may 2010 25 patients (16F:9M) affected by degenerative disc disease (17) and grade 1 or 2 spondylolisthesis (8) were included in this study. Evaluated outcomes were the amount of bleeding, the presence of presacral hematoma, the functional recovery time, the surgery time rate, the x-ray time rate, the complication rate (infection, pelvic visceral injury, postoperative pain).
21 of 25 patients underwent AxiaLIF L5-S1 procedures, 4 of these with a stand alone implant and 17 followed by posterior instrumentation. In the remaining 4 patients, a AxiaLIF 2L L4-S1 procedures is performed. 4 of 25 patients had a perioperative suction drenage. Mean operative time for L5-S1 AxiaLIF procedure was 49 minutes. A 2nd p.o.d. CT pelvic scan of undrained and drained groups showed a mean presacral hematoma of 45 cc and 17 cc respectively reduced one month later to a mean value of 19 cc and 3 cc. Hemoglobin rate mainly reduced of 1,7 g/dL between pre and postoperative time. At one month all patients improved their quality of life significantly but one had a gluteal pain. No patient had perioperative infections or pelvic visceral injuries or required blood transfusions. This study seems to assess that AxiaLIF procedure is a minimally invasive lower spine techique actually. The presacral hematoma presence seems to have no side effect and it may be prevented by perioperative drainage. More large studies are needed to confirm our results.
INTRODUCTION
Trabecular Titanium™ is an innovative material characterised by an high open porosity and composed by multi-planar regular hexagonal cells. It is not a traditional coating and its tri-dimensional structure has been studied to optimise osteointegration. Furthermore, it has excellent mechanical properties, as a very high tensile and fatigue resistance and an elastic module very similar to the that of the trabecular bone. The aim of this study is to evaluate the osteointegration and bone remodelling measuring the longitudinal pattern of change in BMD around a cementless acetabular cup made from Trabecular Titanium™ (Delta TT cup, Lima Corporate, Italy) in primary total hip arthroplasty (THA).
METHODS
Dual-energy x-ray absorptiometry (DEXA) analysis, radiographic evaluation on standard AP and lateral views and clinical evaluation with Harris Hip Score (HHS) and SF-36 were performed at 1 week, 3, 6, 12 months after surgery.
Using a tensor for total knee arthroplasty (TKA) that is designed to facilitate soft tissue balance measurements with a reduced patello-femoral (PF) joint, we examined the influence of pre-operative deformity on intra-operative soft tissue balance during posterior-stabilized (PS) TKA. Joint component gap and varus angle were assessed at 0, 10, 45, 90 and 135° of flexion with femoral trial prosthesis placed and PF joint reduced in 60 varus type osteoarthritic patients. Joint gap measurement showed no significant difference regardless the amount of pre-operative varus alignment. With the procedures of soft tissue release avoiding joint line elevation, however, intra-operative varus angle with varus alignment of more than 20 degrees exhibited significant larger values compared to those with varus alignment of less than 20 degrees throughout the range of motion. Accordingly, we conclude that pre-operative severe varus deformity may have the risk for leaving post-operative varus soft tissue balance during PS TKA.
Co-Cr-Mo alloys represent the most important category of metallic biomaterial for surgical implant applications. Recently, Chiba et al. developed a new type of bio- medical Co based alloy of Co-29Cr-6Mo-0.14N alloy. In this alloy design, the content of N is intended to be controlled to obtain the microstructure consisting of ? single phase. This developed alloy exhibits the lower stacking energy as compared to that of the practical bio-medical Co-Ni based alloy, thereby resulting in the deformation behavior accompanied by strain induced e martensitic transformation.
In this work, the damage process leading to fracture during tensile testing of a biomedical grade Co-29Cr-6Mo-0.14N alloy was analyzed on the basis of three-dimensional damage observation using X-ray tomography and electron backscattered diffraction of the fractured specimen. Initial cracking occurred at grain and annealing twin boundaries, where strain concentrates due to impingement of e-hcp plates formed through strain induced martensitic transformation (SIMT). Crack propagated along interface between ?-fcc matrix and SIMTed e-hcp on {111}, resulting in the occurrence of a quasi-cleavage fracture.
Introduction
Within the reconstruction of unicondylar femoral bone defects with morselized bone grafts in revision total knee arthroplasty (TKA), a stem extension appears to be critical to obtain adequate mechanical stability. Whether the stability is still secured by this reconstruction technique in bicondylar defects has not been assessed. Long, rigid stem extensions have been advocated to maximize the stability in revision TKAs. The disadvantage of relatively stiff stem extensions is that bone resorption is promoted due to stress shielding. Therefore, we developed a relatively thin intramedullary stem which allowed for axial sliding movements of the articulating part relative to the intramedullary stem. The hypothesis behind the design is that compressive contact forces are directly transmitted to the distal femoral bone, whereas adequate stability is provided by the sliding intramedullary stem. A prototype was made of this new knee revision design and applied to the reconstruction of uncontained bicondylar femoral bone defects.
Materials and Methods
Five synthetic distal femora with a bicondylar defect were reconstructed with impacted bone grafting (IBG) and this new knee revision design. A custom-made screw connection between the stem and the intercondylar box was designed to lock or initiate the sliding mechanism, another screw (dis)connected the stem. A cyclically axial load of 500 N was applied to the prosthetic condyles to assess the stability of the reconstruction. Radiostereometry was used to determine the migrations of the femoral component with a rigidly connected stem, a sliding stem and no stem extension.
Objectives
Many reports were shown about the angle of the cup in total hip arthroplasty (THA) with CT-based navigation system. However, there are few reports about the position of the stem. We investigated the position of the stem in navigated THA. We evaluated the position and alignment of stem which were shown on intra-operative navigation system.
Materials and Methods
We treated 10 hips in 10 patients (1 male and 9 females) by navigated THA. 7 osteoarthritis hips and 3 idiopathic osteonecrosis hips were performed THA with VectorVision Hip 2.5.1 navigation system (BrainLAB). Implants were AMS HA cups and PerFix stems (Japan Medical Materials, Osaka). The positions of stem were decided on the 3D model of femur before operation. According to the preoperative planning, we put the implants with navigation system and recorded the position. We measured the position and alignment of stem with 3D template software after operation. We checked for complications.
INTRODICTION
Since 1985, not resorbable crystalline osteoconductive hydroxyapatite (HA) granules were interposed on the interface between bone and bone cement at the cementation (Interface Bioactive Bone Cement: IBBC) of total hip arthoplasty (THA) to prevent generation of connective tissue and osteolysis for the longevity of cemented THA. To prevent the patients from infection, we are planning to use b-tricalcium phosphate (Beta-TCP) impregnated with antibiotics along with HA granules. However, there have been no reports on the loading and release of antibiotics from fine granules of Beta-TCP. Here, we have investigated the loading of antibiotics on Beta-TCP and their release
MATERIALS AND METHODS
Beta-TCP was impregnated with antibiotics such as flomoxef sodium (
The aim of this study was to assess the increase in the anterior diameter of the knee and the impact of this increase on the range of motion and function of the knee.
Twenty-eight patients (34 knees) who underwent Patello-femoral replacement with FPV (Wright Medical) prosthesis between 2005 and 2009 who were identified retrospectively and analyzed using chart and radiological review. Oxford and AKSS knee-scores were gathered prospectively pre-operative and at follow-up.
Trochlear height was measured using lateral radiograph. Trochlear height was compared pre and postoperatively. Patellar height was also measured in preoperative and postoperative skyline view and was compared. The range of movement at six weeks and the Oxford and American knee society knee scores at six months postoperatively were noted. Association between increased anterior height and improved range of motion was studied.
All but three-knees regained full knee extension. Postoperative mean range of flexion of the knee joint was 116 degrees. The mean Oxford knee and the mean American Knee Society Knee Scores significantly improved post-operatively
The trochlear height was increased by 4mms. Patellar height was also increased by 3 mms resulting in average total increase of 7 mms in the anterior-posterior diameter of the knee. We found no relationship between range of motion of the knee and the increase in the anterior-posterior diameter. We found a negative correlation between increase in the antero-posterior and preoperative trochlear and patellar height.
We conclude that FPV Patello-femoral replacement results in correct anatomical reconstruction of the trochlear height rather than ‘overstuffing’ of the patellofemoral joint which can lead to stiffness and failure of resolution of pain post-operatively. This should in turn result in durable improvements in pain and function.
Recently in the literature the indications of unicompartmental knee arthroplasty have been extended by the inclusion of patients with arthritis which is predominantly but not exclusively effecting the medial compartment. The aim of this study is to evaluate the outcome of MAKO unicondylar replacement in the treatment of knee osteoarthritis after the initial surgical insult is worn off to evaluate the impact of residual patellofemoral and lateral osteoarthritis on the outcome of medial unicompartmental knee replacement.
135 patients who underwent uncomplicated 144 MAKO medial unicondylar replacements for knee arthritis were identified and studied. Original radiographs were used to classify severity of patellofemoral and lateral compartmental osteoarthritis in these patients. Severity of patellofemoral and lateral compartmental osteoarthritis was analyzed against Oxford and Knee Society (AKSS) scores and amount of ipsilateral residual knee symptoms at 6 months post-operative period.
Pre-operative Oxford and Knee Society scores, and other comorbidities and long term disability were studied as confounding variables.
We found significant improvement in symptoms and scores in spite of other compartment disease. Poorer outcome was seen in association with comorbidities and long term disability but not when radiographic signs of arthritis in the other compartments were present. Six patients required revision of which three had (lateral facet) patellofemoral disease in the original x-rays.
In conclusion there is no direct relationship between postoperative symptoms and poor outcome and radiographic disease in the other compartments. However when symptoms are severe enough to necessitate revision this is due to patellofemoral and not lateral compartment disease.
The conventional Knee arthroplasty jigs, while being usually accurate, often result in prostheses being inserted in an undesired alignment resulting in poor postoperative outcome. This is especially true about unicompartmental knee replacement. Computer navigation and roboticaly assisted unicompartmental knee replacement were introduced in order to improve surgical accuracy of the femoral and tibial bone cuts.
The aim of this study was to assess accuracy and reliability of robotic assisted, unicondylar knee surgery (Makoplasty) in producing reported bony alignment. Two hundred and twenty consecutive patients who underwent medial robotic assisted unicondylar knee surgery (Makoplasty) performed by two surgeons (RJ & GP) were retrospectively identified and included in the study. Femoral and tibial sagittal and coronal alignments and posterior slope of the tibial component were measured in the post-operative radiographs. These measurements were compared with the equivalent measurements collected during intra-operative period by the navigation to study the reliability and accuracy of femoral and tibial cuts.
Results
We found an average difference of 2.2 to 3.6 degrees between the intra-operatively planned and post-operative radiological equivalent measurements.
In conclusion: assuming appropriate planning, robotically assisted surgery in unicondylar knee replacement will result in reliably accurate positioning of component and reduce early component failures caused by malpositioning. Mismatch between preplanning and post-op radiography is caused by poor cementing technique of the prosthesis rather than wrong bony cuts.
A retrospective single-center review has been performed to gather clinical data on the use of polycarbonate-urethane (PCU) as an articulating bearing material inside a cobalt-chrome (Co-Cr) press-fit acetabular shell.
As of January 2010, the Co-Cr shell and PCU liner have been implanted into 25 total hip patients which were retrospectively followed. The indications for use were in 24 cases of osteoarthritis, and 1 revision case. No patient was lost to follow-up. The average follow-up time was 17.6 months (range 8-27). The average age of these patients was 67.9 (range 44-84), the sex distribution was 14 female and 11 male patients, of whom 15 were right and 10 left side. 24 patients received a total hip replacement with the metal acetabular system and a cementless femoral stem and 1 patient received the metal acetabular shell coupled to a cemented resurfacing head.
None of the cases has had a dislocation, revision, dislodgement, or infection. At follow-up, the mean Harris hip score was 98 points (80-99). X-rays showed good bone-implant contact without any osteolysis or bone rarefaction.
A detailed review of the clinical data of these patients shows that a PCU liner inserted into a Co-Cr acetabular shell is as safe and effective as other commonly used acetabular shells in other total hip systems currently available. No new or unintended adverse or device-related events were discovered with the clinical use of PCU in a Co-Cr acetabular shell.
Introduction
The most common bearing couple used in total knee arthroplasty (TKA) is ultra-high molecular weight polyethylene (UHMWPE) articulating against a CoCrMo alloy femoral component. Although this couple has demonstrated good clinical results, UHMWPE wear has been identified as one of the principal causes for long-term failure of total knee joint replacements1 indicating a need for improvements in TKA bearings technology.
The wear resistance of UHMWPE can be improved by radiation crosslinking; however, in order to get the full benefit of this improved wear resistance, an abrasion resistant ceramic counterface is necessary.2 Since the radiation crosslinking degrades mechanical properties, it is also important to have an optimized radiation dose and subsequent processing. The purpose of this study was to evaluate the long-term wear performance of VERILAST Technology comprising two advanced bearing technologies, abrasion resistant OXINIUM femoral components (OxZr)3-4 and wear/strength optimized 7.5 Mrad crosslinked polyethylene (7.5-XLPE).5
Materials and Methods
Three component assemblies of LEGION(tm) cruciate retaining (CR) OxZr femoral components, 7.5-XLPE tibial inserts were tested on an AMTI knee simulator under displacement control at 1 Hz frequency as described previously.2 The tibial inserts were manufactured from compression molded GUR 1020 UHMWPE, radiation crosslinked to 7.5 Mrad dose, remelted to extinguish free radicals, and sterilized by EtO. The wear test was conducted for 45 Mcycle, which was considered to be a conservative estimate for the amount of cycles that would occur during 30 years of typical in-vivo use based on the relationship between patient age and the number of loading cycles as reported in the literature.6-8
Introduction
Large diameter femoral heads offer increased range of motion and reduced risk of dislocation. However, their use in total hip arthroplasty has historically been limited by their correlation with increased polyethylene wear. The improved wear resistance of highly crosslinked UHWMPE has led a number of clinicians to transition from implanting traditionally popular sizes (28mm and 32 mm) to implanting 36 mm heads. Desire to further increase stability and range of motion has spurred interest in even larger sizes (> 36 mm). While the long-term clinical ramifications are unknown, in-vivo measurements of highly crosslinked UHMWPE liners indicate increases in head diameter are associated with increased volumetric wear [1]. The goal of this study was to determine if this increase in wear could be negated by using femoral heads with a ceramic surface, such as oxidized Zr-2.5Nb (OxZr), rather than CoCrMo (CoCr). Specifically, wear of 10 Mrad crosslinked UHMWPE (XLPE) against 36 mm CoCr and 44 mm OxZr heads was compared.
Materials and Methods
Ram-extruded GUR 1050 UHMWPE was crosslinked by gamma irradiation to 10 Mrad, remelted, and machined into acetabular liners. Liners were sterilized using vaporized hydrogen peroxide and tested against either 36 mm CoCr or 44 mm OxZr (OXINIUM(tm)) heads (n=3). All implants were manufactured by Smith & Nephew (Memphis, TN).
Testing was conducted on a hip simulator (AMTI, Watertown, MA) as previously described [2]. The 4000N peak load (4 time body weight for a 102 kg/225 lb patient) and 1.15 Hz frequency used are based upon data obtained from an instrumented implant during fast walking/jogging and have previously been shown to generate measurable XLPE wear [2,3]. Lubricant was a serum (Alpha Calf Fraction, HyClone Laboratories, Logan, UT) solution that was replaced once per week [2]. Liners were weighed at least once every million cycles (Mcycle) over the duration of testing (∼ 5 Mcycle). Loaded soak controls were used to correct for fluid absorption. Single factor ANOVA was used to compare groups (a = 0.05).
Background
Performing total knee replacement needs both bony & soft tissue consideration. Late John Insall advocating spacer blocks with concept of balanced & equal flexion – extension Gap. Although we usually excise both ACL & PCL, still it is possible to retain more soft tissue. Both PCL retaining & sacrificing Require intact collaterals for stability. Superficial MCL & LCL should be preserved, if possible. after PCL removal the following advantages could obtain: More correction of fixed varus or valgus deformity, More surgical exposure. but there are no proved disadvantages like; increasing in stress & loosening of bone-cement-prosthesis interface, specific clinical difference in ROM, forward lean during stepping up, proprioception inferiority. in other hand Over tight PCL cause excessive rollback of tibia & knee hinges open, preventing flexion (booking), and Severe posteromedial poly wear in poor balance PCL might be happened.
Mid range laxity when Post. Capsule is tight, even with correct tensioning in full extension & 90 degree flexion, may occur (and secondary collateral ligaments imbalance throughout ROM). There is a major effect of capsular contracture in coronal mal alignment with flexion contracture. Full MCL releases not only correct fixed varus but also open the medial space in flexion. MCL & post. Capsule has combined valgus resistant effect in extension. PCL release increase flexion gap more, May be necessary to release something that affect extension gap as compensated balancing (Post.medial capsule). Any flexion contracture need to posterior capsulotomy & post. Condyle osteophyte removal before femoral recut.
So it is possible to perform posteromedial capsulotomy prior to superficial MCL release.
Method
From May to Dec. 2009, 22 patients (23 knees) with primary DJD and varus deformity of knees were operated by myself with joint replacement. most patients had some degree of varus correction in flexion, passively. the varus angle was less than 25∗, means mild to severe but not decompensated. For soft tissue balancing during Total knee arthroplasty I consider the following steps;
Medial capsule & deep MCL release, PCL release, Posteromedial capsulotomy, semimembranous release, Superficial MCL release, Pes anserinous release.
The Average Age was 64.74 years, 19 patients were female (83%) and one of them had bilateral TKA simultaneously. Lt Knee was operated in 14 cases (70% of 24). Spinal anesthesia was applied in 82%. 10 patients were operated with MIS technique and 13 patients with Standard medial parapatellar incision.
Background
There are many difficulties during performing total hip replacement in high riding DDH. These difficulties include: In Acetabular part: bony defect in antero lateral acetabular wall/finding true centre of rotation/shallowness of true acetabulum/hypertrophied and thick capsular obstacle between true and false acetabulum In Femoral part: small diameter femoral shaft/excessive ante version/posterior placement of greater trochanter anatomic changes in soft tissue & neurovascular around the hip including: adductor muscle contracture/shortening of abductor muscles/risk of sciatic nerve injury following lengthening of the limb after reduction in true acetabulum/vascular injury
The purpose of this lecture is how to manage above problems with using reinforcement ring (ARR) for reconstruction of true acetabulum and step cut L fashion proximal femoral neck shortening osteotomy in a single stage operation
Method
23 surgeries in 19 patients, including 18 female and one male were performed by me from Jan. 1997 till Dec. 2009. Six patients had bilateral hip dislocation, but till now only four of them had bilateral stepped operation. Left hip was involved in 15 cases (65.2%). The average age was 40 years old. All hips were high riding DDH according to both hartofillokides and crowe classification. Reconstruction of true acetabulum was performed with aid of reinforcement ring and bone graft from femoral head in all cases. Trochantric osteotomy was done in all, followed by fixation with wire in 22 cases which needed two revisions due to symptomatic non union (9%). Hooked plate was use in one case for trochantric fixation. Due to high riding femur, it was necessary to performed femoral shortening in neck area as a step cut L fashion.
In two patient, one with bilateral involvement, after excessive limb lengthening following trial reduction, it was necessary to performed concomitant supracondylar femoral shortening. (3 cases = 13%)
22 mm cup & miniature muller DDH stem were used in 18 cases (78.26%). In 5 cases, one bilaterally, non cemented stem and 28 mm cemented cup in ring were used.
Primary adductor tenotomy was performed in 9 cases. Secondary adductor tenotomy needed in 2 cases (totally = 47.82%). Repair of iatrogenic femoral artery tear after traction injury with retractor, occurred in 2 cases (8.69%).
All patients evaluate retrospectively. Average follow up month is 68.7.
Minimal invasive surgery (MIS) is accepted when the scar is 10 cm or less. The anterior and the antero-lateral approaches had gained recently interest in the total hip arthroplasty because they allow complete muscle sparing. The postero-lateral and lateral approaches were propsed to be less satisfactory from this point of view. The goal of this paper was to report an objective and carfull assessment of the advantages of the minimal invasive posterior approach in short stem (Nanos) total hip arthroplasty.
Material and methods
From juli 2005 to march 2009 a total of 113 (70 males,53 female) uncemented Nanos-short-stem prothesis were implanted in 111 patients. The patiens average age was 53 years (33-73). The indication for this procedure was predominantly coxarthrosis. In all cases a minimal invasive posterior approach was used. The mean follow up period was 2,5 years (range 6 months- 4,5 years). The patients were assessed using Harris Hip Score and radiologically to detect any bone changes, the stand of the prothesis and peri-articular ossifications
Results
The perioperative Harris Hip Score was 53 (28-77), postoperative was 94 (86-100). Untill now we have not discovered any prothesis specific complications. Radiological follow up examinations showed the development of increasing trabecular reinforciment of the femoral neck and pertrachanteric regions. There is no evidence of any loosing or migration of the prothesis. No luxation. Calcification was noted in 8 cases (Grad 1), 4 cases(Grad 2), 1 case (Grad 3). In 3 cases we have to change the cup because of malposition
Background
Bouchard -arthrose is often familial and affect predominantly females. It starts as acute inflammation of the soft tissue and with time may progress to severe deformity and limitation of movement. In the early phases one of the most commen operation in the management is the synovialectomy. In late stages with severe destruction and deformity of the joint arthrodesis can be carried out. However, arthrodesis may lead to severe loss of function. One of the most commonly and world wide used prothesis to maintain movement is the Swanson –spacer.
Material and Methods
20 Swanson-implants in 14 patients (12 female,2 male) were evaluated subjectively and objectively using PIJA-score (Interphalangeal-joint –score) and Dash –score. The follow period was 4.6 years (range 1-11 years).
Background
The trapeziometacorpal joint (TMJ) of the thumb is a common site of primary osteoarthritis. Pain, crepitis and instability secondary to subluxation are common symptoms associated with TMJ arthritis. Conservative therapy help to control symptoms however with time, many patients progress with pain, deformity and functional limitation. The goals of operative intervention are to restore stability and strength, decrease pain and to provide a functional range of motion. Francobal-prosthesis may fulfil these criterions.
Technique
We implanted the prosthesis through a dorso-radial straight longitudinal or slightly curved skin incision. A dorsal capsulotomy is performed and at this step adduction deformity should be addressed. An osteotomy of the proximal surface of the first metacarpal is made perpendicular to the long axis of the medullary cavity followed by reaming of the medullary cavity and then a trial fit. This is followed by preparation of the trapezium including removing any osteophytes, drilling of a cavity. Dental burs may be used at this step to deepen the cavity. The process of cementation started by cementation of the cup with its opening neutral to the joint surface, and if there is any muscle tension, bone is removed from the metacarpal before the metacarpal component is cemented. Reduction is achieved by snapping. The capsule and wound are closed and the thumb is immobilised in an adduction splint for ten days.
The weight bearing axis of the limb goes from the pelvis to the ground and includes the hindfoot. However, the influence of hindfoot alignment on mechanical axis deviation and overall limb alignment after total knee arthroplasty (TKA) is unknown. This study aimed to assess the change in hindfoot alignment after TKA for knee osteoarthritis, the difference in mechanical axis deviation at the knee when calculated using the ground mechanical axis as compared to the conventional mechanical axis, and the effect of hindfoot alignment on the overall postoperative limb alignment after TKA.
We evaluated the pre- and postoperative hip-knee-ankle (HKA) angle, conventional mechanical axis deviation (CMAD), ground mechanical axis deviation (GMAD), and tibiocalcaneal angle (TCA) in 125 patients who underwent 165 consecutive TKAs. Overall, the change in pre- and postoperative mean TCA was not significant (p=0.48) whereas it was significant (p=0.01) in knees with =15° deformity where the hindfoot valgus decreased by approximately 25%. Preoperatively, there was no significant difference between mean CMAD and mean GMAD whereas postoperatively the difference was significant (p=0.0001). Hindfoot valgus alignment of =10° was present in 22.5% of limbs and 29% limbs had a postoperative GMAD of =10 mm in spite of the limb alignment being restored to within 3° of neutral after TKA.
Despite accurate restoration of limb alignment after TKA, as a result of persistent hindfoot valgus alignment the ground mechanical axis may pass lateral to the centre of the knee joint - with potential detrimental effects on bone, ligaments and implants.
Genu recurvatum deformity is uncommon in arthritic knees undergoing total knee arthroplasty (TKA). We retrospectively analysed radiographs and navigation data to determine the clinical and radiographic results of computer-assisted TKA in knee arthritis with recurvatum deformity.
Based on alignment data obtained during computer assisted (CAS) TKA, 40 arthritic knees (36 patients) with a recurvatum deformity of at least 5° were identified. The mean recurvatum deformity was 8.7° (6° to 14°). On preoperative standing hip-ankle radiographs, 23 limbs (57.5%) had a mean varus deformity of 169.4° (153° to 178°) and 17 limbs had a mean valgus deformity of 189.2° (182° to 224°). The intraoperative navigation data showed mean tibial resection of 7.5mm (4.6 to 13.4mm) and distal femur resection of 7.5mm (3.3 to 13mm) with a mean final extension gap of 21.2mm and a flexion gap at 90° of 21.1mm and on extension. On table, the mean knee deformity in sagittal plane was 3° flexion (1.5° to 4.5° flexion).
Postoperatively, the mean HKA angle on standing hip-ankle radiographs was 179.2° (177° to 182°). On postoperative lateral radiographs, joint line in extension was moved distally in 35 limbs by 2.3mm (0.3 to 4mm) and proximally in 5 limbs by 2.2mm (2.2 to 2.4mm); the mean preoperative posterior femoral offset of 28.7 mm changed to 27.9 mm postoperatively. At a mean follow up 28 months (14- 48 months) the knee, function, and pain scores improved by 61, 48, and 28 points, respectively and there was no recurrence of recurvatum deformity at final follow up.
Genu recurvatum is a notoriously difficult condition to address at TKA. The challenges are to be able to detect it at surgery and take appropriate measures in terms of resection and releases to correct it satisfactorily. Computer assisted TKA helps to achieve excellent deformity correction, limb alignment, gap balancing and function in patients with recurvatum deformity by accurately quantifying and helping to modify the amount of bone cuts and titrate soft tissue release.
Computer navigation has been advocated as a means to improve limb and component alignment and reduce the number of outliers after total knee arthroplasty (TKA). We aimed to determine the alignment outcomes of 1500 consecutive computer-assisted TKAs performed by a single surgeon, using the same implant, with a minimum 1 year follow-up, and to analyze the outliers. Based on radiographic analysis, 112 limbs (7.5%) in 109 patients with mechanical axis malalignment of > 3° were identified and analyzed.
The indication for TKA was osteoarthritis in 107 patients and rheumatoid arthritis in 2 patients. Fifty-eight patients (53%) had undergone simultaneous bilateral TKA and 13 patients (12%) had a BMI >30. Preoperative varus deformity was seen in 100 limbs and valgus deformity in 12 limbs. Thirty limbs (27%) had an extra-articular deformity (2 post HTO limbs, 3 malunited fractures, 1 stress fracture, 21 severe femoral bowing and 3 tibial bowing) and 21 limbs (19%) had severe lateral laxity or subluxation. Thirty-eight limbs (34%) had a preoperative deformity of =10° and 24 limbs (21.5%) had varus or valgus deformity of >20°.
Postoperatively, 11 limbs were malaligned at ±3°, 74 limbs at ±4°, 22 limbs at ±5°, 2 limbs at ±6°, and 2 limbs at ±7°. Coronal plane malalignment of > ±3° of the femoral component was seen in 28 limbs, tibial component in 32 limbs, and both femoral and tibial components in 13 limbs. Twenty-six limbs with preoperative varus deformity had a postoperative valgus alignment of >183° and 3 limbs with valgus deformity had a postoperative varus alignment of <177°.
The incidence of outliers for postoperative limb alignment was low at 7.5% with the tibial component showing a higher incidence of coronal malalignment. Malalignment may be more common in cases of simultaneous bilateral procedures, preoperative limb alignment of =10°, limbs with extra-articular deformities and severe lateral instability. There was a tendency towards over-correction of the hip-knee-ankle axis in both varus- and valgus-deformed knees. Further detailed statistical analysis of the data will be presented.
This is the largest single-surgeon series of consecutive navigated TKAs and consequently the largest analysis of outliers that highlights which knees are likely to fall outside the +3 degrees of acceptable alignment and which therefore behoove the surgeon to exercise greater caution.
Dislocation after total hip arthroplasty (THA) is one of the most serious complications. We recently modified the design of Lateral Flare femoral component (RevelationV2) with six degrees lower anteversion to reproduce the normal hip condition in Japanese. In addition, we added 10-degree slope on the posterior neck to prevent dislocation especially aimed to high anteversion cases. The purpose of this study is to verify the clinical outcome after this design modification.
Hospital records and database were retrospectively reviewed. We investigated 46 consecutive hips in 43 patients who underwent primary total hip arthroplasty using RevelationV2 from September 2007 to August 2009. All patients implicated preoperative planning using CAT scan with their informed consents.
The mean age and BMI at surgery were 63 years old and 23.1. Preoperative diagnosis was osteoarthritis (40/46: 87%), rheumatoid arthritis (2/46: 4%) or avascular necrosis of femoral head (4/46: 9%). There were 41 hips (89.2%) of Crowe I, 3(6.5%) of Crowe II and 2(4.3%) of Crowe III. Preoperative femoral neck anteversion averaged 28 degrees, whereas postoperative combined anteversion (the sum of femoral neck anteversion and anterior cup inclination) averaged 46 degrees. During follow up, 5 complications, in details, 3 mild peroneal nerve palsy, 1 pulmonary embolism and 1 dislocation following deep infection were reported. In conclusion, although no ordinal dislocation was found in this series, longer observation will need to judge appropriateness of this new component.
Acetabular component malpositioning is the most common reason for instability and wear resulting in revision total hip arthroplasty (THA). The current study aimed to assess a novel mechanical navigation device which was designed to simply and efficiently indicate appropriate cup orientation during surgery. The accuracy was compared to a series of hip arthroplasties performed using CT-based computer-assisted cup placement.
The study group consisted of 70 THAs performed using the mechanical device. The control group consisted of 146 THAs performed using CT-based computer navigation. Postoperative cup positioning was measured using a validated 2D/3D-matching method. An outlier was defined outside a range of ± 10 degrees from the planned inclination or anteversion.
In the study group the mean accuracy for inclination was 1.3 ± 3.4 (-6.6 – 8.2) and 1.0 ± 4.1 (-8.8 – 9.5) for anteversion with no outliers for either parameter. In the control group the accuracy for anteversion (3.0 ± 5.8 [-11.8 - 19.6]; p=0.6%) and the percentage of outliers (6.8%; p=3.3%) differed significantly. The accuracy for inclination (3.5 ± 4.1 [-12.7 - 9.5]; p=21.4%) and the percentage of ouliers (4.8%; p=9.9%) did not differ significantly.
The use of this mechanical navigation device can result in similar accuracy of acetabular cup orientation compared with CT-based surgical navigation. All cups were placed within a zone of ± 10 degree range of inclination and anteversion. This mechanical navigation device allows accurate cup navigation with minimal additional time and equipment.
Introduction
The use of less invasive techniques for total hip arthroplasty (THA) has remained controversial with some studies showing a higher incidence of complications. The technique of performing total hip arthroplasty through a superior capsulotomy was developed to maximally preserve the soft tissue envelope surrounding the hip. The current study assesses the recovery and complications of hips replaced using conventional and tissue preserving techniques.
Methods
206 hips in 191 patients with a mean follow-up of 4.3 ± 1.0 (range, 3.2 – 5.9) years underwent total hip arthroplasty using the superior capsulotomy technique. The mean age at operation was 55.7 ± 12.9 (19 – 85) years and the operation was performed for 106 hips (51%) in men. The surgical technique involves exposing the superior hip joint capsule posterior to the medius and minimus, and anterior to the short external rotators. The femur is prepared with the femoral head in place and then the femoral head is excised without dislocation. These 206 hips were compared to a cohort of 279 hips replaced using the transgluteal exposure (control group). These 2 series were controlled for complexity and demographic factors. Recovery was evaluated using the Merle d'Aubigné score at 6 and 12 weeks postoperatively.
Total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH) has been associated with increased rates of complications and revision. Hip instability and wear-induced osteolysis are among the more common and serious of these problems. The current investigation prospectively assessed the survivorship and clinical results of patients with DDH treated by alumina ceramic-ceramic THA.
We investigated 161 consecutive hips in 145 patients with DDH classified as Crowe type I (131 hips, 81%), II (26 hips, 16%), III (2 hips, 1%), and IV (2 hips, 1%). All patients had an uncemented titanium acetabular component with a flush mounted alumina ceramic-ceramic bearing. The mean age at operation was 48.0 ± 12.2 years (range, 18 – 79 years). The preoperative Merle d'Aubigné score was 11.4 ± 1.7 (6 – 15). 27 hips (17%) had at least one previous surgical procedure. 92 hips (57%) were replaced with the use of surgical navigation for acetabular component positioning. The mean cup diameter was 49.9 ± 3.4 mm (46 – 60 mm). 88 (55%) bearings were 28mm and 73 (45%) bearings were 32mm.
At a mean follow-up of 6.1 ± 2.5 years (2 – 11.3 years), the mean Merle d'Aubigné score was 17.4 ± 0.9 (14 – 18). There were no cases of osteolysis or dislocation. There was one reoperation of an early displaced cup. In addition, there was one calcar crack that was cerclaged, one intraoperative trochanteric fracture also repaired at surgery. No patient complained of squeaking. 94 patients with 100 hips (61%) completed a questionnaire specifically asking for squeaking. None of these patients reported squeaking. The 10-year Kaplan Meier survivorship of the implants (revision of any component for any reason) was 99.4% (95% confidence interval 98.2-100%).
Results of ceramic-ceramic THA in young patients with low to middle graded DDH after two to eleven years follow-up are promising with no radiographic signs of osteolysis or dislocation.
Introduction
The initial mechanical stability of cementless femoral stems in total hip arthroplasty is an important factor for stable biological fixation. Conversely, insufficient initial stability can lead to stem subsidence, and excessive subsidence can result in periprosthetic femoral fracture due to hoop stress. The surface roughness of stems with a surface coating theoretically contributes to initial mechanical stability by increasing friction against the bone, however, no reports have shown the effect of surface roughness on stability. The purpose of this study was to evaluate the effect of differences in surface roughness due to different surface treatments with the same stem design on the initial stability.
Materials and Methods
Proximally titanium plasma-sprayed femoral stems (PS stem) and proximally grit-blasted stems (GB stem) were compared. The stem design was identical with an anatomic short tapered shape for proximal fixation. The optimum size of PS stem based on 3D templating was implanted in one side of 11 pairs of human cadaveric femora and the same size of GB stems was implanted in the other side. After implantation, the specimens were fixed to the jig of a universal testing machine in 25cm of entire length so that the long axis of the femur was positioned at 15-degrees adduction to the vertical. Vertical load tests were conducted under 1 mm/minute of displacement-controlled conditions. After 200 N of preload to eliminate the variance in the magnitude of press-fit by manual implantation, load was applied until periprosthetic fracture occurred.
Introduction
Current standard cups of metal on metal resurfacing hip arthroplasty (RHA) have no dome holes and it is very difficult for surgeons to confirm full seating of these cups. This sometimes results in gap formation between the cup and acetabular floor. Although the incidence of initial gaps using modular press-fit cups with dome screw holes has been reported to range from 20 to 35%, few studies have reported the incidence of gap formation with monoblock metal cups and its clinical consequences in RHA. The purpose of this study was to investigate retrospectively the incidence of initial gap formation and whether the initial gap influences the clinical results in RHA.
Material and Method
RHA was performed on 166 hips of 146 patients using the Birmingham Hip Resurfacing (BHR) (MMT, UK) between 1998 and 2007. Mean age at operation was 48.7 years (range, 19-85 years). Mean duration of follow-up was 6.9 years (2.0-10.6). Acetabular reaming was performed with the use of hemispherical reamers and the reamer size was increased up to an odd number diameter which provided tight rim fit in the antero-posterior direction. The same size hemispherical provisional cup with dome holes and slits was used to check the cavity for complete seating. If the provisional cup could not be seated on the floor, reaming was repeated with the same reamer to remove the rim bump until full seating was achieved. Acetabular cups of 1mm larger diameter were impacted into the acetabulum by a press-fit technique. After press-fit fixation, the stability of the cups was confirmed with a synchronized movement of the pelvis and the cup inserter by applying a gentle torque. Clinical evaluation was performed using WOMAC at the latest follow-up. Radiographic assessments were performed using radiographs immediately after the surgery, at 3 weeks, 3 months, 1 year, and then annually thereafter. We evaluated the height of the gap between the cup and acetabular surface, cup inclination angle, cup migration and the time to gap filling. To investigate the relationship between the magnitude of the gap and the radiographic results, the patients were divided into two groups according to the height of the initial gap; the cases with a gap of less than 3 mm on the initial radiograph were grouped into a small gap group, the cases with a gap of 3mm or more were grouped into a large gap group. We compared the changes in the height of the gap, in the cup inclination angle and the cup migration between the groups.
We hypothesize that tethering adhesions of the quadriceps muscle are the major pathological structures responsible for a limited range of motion in the stiff arthritic knee. Forty-two modified quadriceps muscle releases were performed on 24 patients with advanced osteoarthritis scheduled for total knee arthroplasty. The ranges of motion were documented intraoperatively both before and immediately after the release. Passive flexion improved significantly in all patients (mean, 32.4 degrees of improvement, P < .001) following a modified quadriceps release, despite any presence of osteophytes or severe deformities. These results strongly implicate adhesions of the quadriceps muscle to the underlying femur, which prevent the distal excursion of the quadriceps tendon, as the restrictive pathology preventing deep flexion in patients with osteoarthritis.
60 patient where included in this comparative study. Patients where divided into 3 groups. Group A including TKR done navigation guided in a navigation techniques experienced center. Group B including patient done navigation guided in less experienced center. Group c including patients done conventionally by an experienced surgeon. Accuracy was the primary end point. Where an independent observer was requested to comment on the post operative x-ray blindly and to measure accuracy using software. Result showed no significant difference in post operative radiological accuracy in the 3 groups.
Introduction
Resistant organisms are difficult to eradicate in infected total knee arthroplasty, and treatment of methicillin-resistant Staphylococcus aureus (MRSA) is especially challenging. Whereas most surgeons use antibiotic-impregnated cement during revision to treat infection, the delivery of the drug in adequate doses is limited in penetration and duration. This study presents the 2- to 8-year prospective results of one-stage revision and intraarticular antibiotic infusion protocol used to treat MRSA.
Methods
Eighteen knees (18 patients) with methicillin-resistant Staphylococcus aureus were treated between January 2001 and January 2007 with one-stage revision protocol that included débridement, uncemented revision of total knee components, and intraarticular infusion of 500 mg vancomycin via Hickman catheter once or twice daily for 6 weeks. (Figure 1) No intravenous antibiotics were used after the first 24 hours. Serum vancomycin levels were monitored to maintain levels between 3 and 10 μg/mL. The mean serum vancomycin peak concentration was 6 ± 2 μg/mL and the mean serum vancomycin trough concentration was 3 ± 1 μg/mL at 2 weeks postoperative.
Introduction
Recent clinical studies found no apparent reduction in wear using yttria-stabilized zirconia (Y-TZP) instead of cobalt chromium alloy femoral heads bearing against cross-linked UHMWPE. The purpose of this study was to compare the surface topography of retrieved Y-TZP and magnesia-stabilized zirconia (Mg-PSZ) femoral heads and evaluate the influence of time
Materials and Methods
Y-TZP (n = 18) and Mg-PSZ (n = 17) femoral heads were retrieved from revision THA. Heads were cleaned and scanned by optical profilometry (magnification = 10x) at three locations per specimen. After subtracting the curvature of the heads, roughness statistics (Sa, Ssk) were calculated and averaged for each specimen and then correlated to age
Purpose
To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components.
Materials & Methods
All patients undergoing primary total hip replacement surgery at our institution are entered prospectively into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. The patients are re-examined, re-x-rayed and re-scored at 3 months, 6 months and 1 year after surgery and yearly thereafter.
Using this database we are able to identify patients who have undergone total hip replacement using one of two geometric variants of the acetabular component. The first design is hemispherical and the second design has a peripheral rim expansion designed to increase initial press-fit stability.
Aim
This prospective randomised controlled trial aims to compare the clinical and radiological outcomes of ceramic on ceramic, cobalt chrome on ultra-high molecular weight polyethylene, and cobalt chrome on highly cross-linked polyethylene bearing surfaces at a minimum of five years.
Methods
One hundred and two primary total hip replacements were performed in ninety one patients between February 2003 and March 2005. All patients were younger than 65 (mean 52.7, 19-64). They were randomised to receive one of the three bearing surfaces. All patients had 28mm articulations with a Reflection uncemented acetabular component and a Synergy stem (Smith & Nephew, Memphis, Tennessee). Patients were followed up periodically up to at least sixty months following surgery. Outcome measures included WOMAC and SF12 scores. Radiological assessment included implant position, evidence of osteolysis and measurement of linear wear.
Introduction
Femoro-acetabular impingement (FAI) is a common source of impaired motion of the hip, often attributed to the presence of an aspherical femoral head. However, other types of femoral deformity, including posterior slip, retroversion, and neck enlargement, can also limit hip motion. This study was performed to establish whether the “cam” impinging femur has a single deformity of the head/neck junction or multiple abnormalities.
Materials and Methods
Computer models of 71 femora (28 normal and 43 “cam” impinging) were prepared from CT scans. Morphologic parameters describing the dimensions of the head, neck, and medullary canal were calculated for each specimen. The anteversion angle, alpha angle of Notzli, beta angle of Beaulé, and normalized anterior heads offset were also calculated. Average dimensions were compared between the normal and impinging femora.
Introduction
Proper rotational alignment of the tibial component is a critical factor affecting the outcome of TKA. Traditionally, the tibial component is oriented with respect to fixed landmarks on the tibia without reference to the plane of knee motion. In this study, we examined differences between rotational axes based on anatomic landmarks and the true axis of knee motion during a functional activity.
Materials and Methods
24 fresh-frozen lower limb specimens were mounted in a joint simulator which enable replication of lunging and squatting through application of muscle and body-weight forces. Kinematic data was collected using a 3D motion analysis system. Computer models of the femur and tibia were generated by CT reconstruction. The motion axis of each knee (TFA) was defined by the 3D path of the femur with respect to the tibia as the knee was flexed from 30 to 90 degrees. The orientation the TFA was compared to 5 different anatomic axes commonly proposed for alignment of the tibial component.
Introduction
Although the “learning curve” in surgical procedures is well recognized, little data exists documenting the accuracy of surgeons in performing individual steps of orthopedic procedures. In this study we have used a validated computer-based training system to measure variations instrument placement and alignment in TKA, specifically those relating to tibial preparation.
Methods
Eleven trainees (surgical students, residents and fellows) were recruited to perform a series of 43 knee replacement procedures in a computerized training center. After initial instruction, each trainee performed a series of four TKA procedures in cadavers (n=2) and bone replicas (n=2) using a contemporary TKA instrument set and the assistance of an experienced surgical instructor. The Computerized Bioskills system was utilized to monitor the placement and orientation of the proximal tibial osteotomy and the tibial tray.
The objective of this study was to consider whether an impaction bone graft (IBG) with their own bone tips surrounded with an X-changed rim mesh was useful when en bloc bone inplantation was not possible for a total knee replacement with large bone defect.
Materials and Method
4 cases and 5 knees (OA: 2 cases 3 knees, RA: 2 cases 2 knees) more than 2 years after the IBG procedure was done using X-changed rim mesh for the large medial tibial defect. All 4 cases were ladies, with the average age being 66.2 years old at that point of the procedure. A medial and posterior release for the connective tissues of knee was performed. The post and pre radiographic evaluations were done by knee society score and JOA score. All the defect or abrasion of the weighted surface was more than 5 mm from the last stage of osteoarthritis. We used a posterior-stabilized type of TKA (Zimmer nexgen), then took radiographs at pre and post operation periods and evaluated the knee scores, FTA, radiolucent line, range of motion and more than 2 years after the operation.
Result
The graft bones were not depressed after more than 2 years and all the patients were satisfied the condition of their knees and made no mention of any knee pain. The average range of motion of their knee joint was: Pre-operation, passive flexion 133°, passive extension -21°; Post-operation, passive flexion 149°, passive extension -3°. All of the patients did not complain during movement and their walking ability including going up and down stairs was not reduced more than 2 years later. The component placement angle was not changed. The radiolucent line of the femur and tibiae did not appear.
The average femoro-tibial angle improved from 197° to 173° over the course of two years. The femoral/tibial component setting angle was not changed more than 2 years after the TKA operation procedure. Radiolucent zone and component sinking was not seen on both side of femur and tibiae.
INTRODUCTION
We have conducted interface bioactive bone cement method (IBBC) in total hip arthoplasty (THA) to prevent generation of connective tissue and osteolysis for the longevity of cemented THA since 1985, in which non-resorbable crystalline osteoconductive hydroxyapatite (HA) granules were interposed on the interface between bone and bone cement. To prevent the patients from infection, we use HA granules impregnated with antibiotics. However, there have been no reports on the loading and release of antibiotics from fine granules of HA. Here, we have investigated the loading of antibiotics on HA and their release
MATERIALS AND METHODS
HA was impregnated with antibiotics such as flomoxef sodium (
Background
Patellar ligament rupture is an uncommon but devastating complication of total knee arthroplasty. Many predisposing factors may lead to rupture of the ligament during or shortly after surgery. The most common predisposing factor is extensive release of the ligament to improve exposure in difficult cases or revisions.
Purpose
The purpose of this study is to show the outcome of new technique for repair of overstretched patellar ligament during total knee arthroplasty.
Background
Standard implants (PCL retaining or posterior stabilized types) can be used if soft tissue balancing techniques allow the implant to tension and stabilize the joint in flexion and extension. In severe varus, Greater constraint implant may be used. The indications for the use of these components were inability to balance the knee in both flexion and extension because of severe deformities or intraoperative incompetence of the medial collateral ligament after aggressive release.
Material and methods
Fourteen patients with twenty knees had severe varus deformity with average preoperative tibio-femoral angle 25°. The average age was 56 years (from 48 to 64). There was nine males and five females. The pre-operative diagnosis was primary osteoarthritis in 90% of patients and rheumatoid arthritis in 10% (two knees out of twenty). The average follow up was 39 month (from 27 to 57 month). Legacy Constrained Condylar Prosthesis (modular constrained knee of Zimmer) was used in all cases with stemmed both tibial and femoral components.
The Gibson and Moore postero-lateral approach is one of the most often used in hip replacement. The advantage of this approach is an easy execution but it's criticized because of its invasivity to muscle-tendinous tissues especially on extrarotators muscles and because of predisposition to posterior dislocation.
Since June 2003 we executed total hip replacements using a modified postero-lateral approach which allows to preserve the piriformis and quadratus femoris muscles and to detach just the conjoint tendon (gemelli and obturator internus). Articular capsule is preserved and it will be anatomically sutured at the end of the procedure as well as the conjoint tendon with two transossesous sutures. Piriformis and quadratus femoris muscles result untouched by this approach.
We have executed 500 surgeries with this modified approach.
We have used different stems (straight, anatomical, modular and short) and press fit acetabular cup with polyethylene or ceramic insert and we have always used 36 mm femoral heads when allowed by the cup dimensions. We have used any size both of stems and cups without limitation due to the surgical approach.
The mean age is 61.8 y.o., 324 females and 176 males.
Obese patients, hip dysplasia Crowe 3 and 4 and post traumatic arthrosis are exclusion factors for the execution of this approach. If possible we have maintained the capsulo-tendinous less invasivity. The BMI is not an excluding factor because it's just the gluteus region that is an important factor to decide if to execute or not a less invasive approach.
Analyzing our 500 cases we didn't have any case of malpositioning of the stem in varus or valgus (more than 5°) and considering acetabular cup we had the tendency to position it in valgus position (not more than 40°) in the first 20 cases.
No leg discrepancy more than 1 cm were observed.
Intra-operative blood loss have been reduced of about 30 % and 50% in the post-operative.
All the patients were able to active hip mobilization within the first day after surgery with a mean range of motion of 0-70°.
The patients were mobilized the first day after surgery and 80% of them were able to assisted walk within second day after surgery.
The mean time of stay in hospital was 6.8 days.
After 4 weeks 98% of the patients were able to walk without crutches.
One case of deep infection were evaluated and then solved with surgical debridement; no wound dehiscence.
We had 1 case of anterior hip dislocation in dysplastic arthrosis due to a technical mistake.
In 1 case we had femoral nerve palsy, then solved, probably because of anterior retractor malpositioning.
We had 5 cases of piriformis muscle contracture without sciatic nerve palsy, then solved.
We think that for total hip replacement this conservative postero-lateral approach, thanks to capsule-tendinous modification we have adopted, could be considered an anatomical approach, which doesn't present more dislocation risks compared to other approaches to the hip also thanks to the introduction of 36 mm femoral head that gives more stability and proprioceptiveness.
Besides this approach gives the possibility of a shorter rehabilitation as seen above and it could be consider optimal for total hip replacement.
Millions of people suffer from bone and joint inflammatory problems and usually result in extreme cases with total joint replacement. Most commonly affected joints are the hip and the knee. Over the past 20 years there has been a revival in interest of metal-on-metal hip replacements. Various alloys have been used in joint replacement, the most successful in the Cobalt-based alloys. As compared to others the cobalt based alloys have higher wear resistance and therefore less risk of failure. The most common Co-based alloy used in clinical application is the ASTM F75 alloy, which is extensively used in femoral and acetabular components. Conventional methods to fabricate the alloy are via cast or wrought techniques. Wrought alloys are better than their cast materials due to their superior mechanical properties as the forging process promotes plastic deformation. An alternative method of fabrication is via powder processing and has shown significant improvements to produce finer grained materials, which relate to enhancement in properties, such as strength, toughness, ductility.
One of the key stages of powder processing is sintering of the powder to fuse the particles together. A superior but simple sintering processing is spark plasma sintering (SPS), which produces highly dense materials with minimum grain growth. This is achieved by a pulsed electrical current heating the material while applying a pressure to compact the powdered material. This process has the ability to densify nanopowders, in order to produce microstructures with finer grains and superior mechanical properties.
Using SPS and nanopowders for the first time, we have been able to prepare the ASTM F75 cobalt–chromium–molybdenum (Co–Cr–Mo) orthopaedic alloy composition. In this work we have investigated, the effect of processing variables on the structural features of the alloy (phases present, grain size and microstructure). We have been able to produce specimens of >99% of the theoretical density. The structures were free of carbides, which a vital breakthrough. Detrimental carbide phases in the microstructure as found in the more conventional methods of fabrication have shown to cause problems in wear. The compacts are of higher hardness than cast or wrought products despite the absence of carbides in the microstructure. The gain in hardness is because of the presence of oxides in the microstructure and we hope to quantify the oxide content in the future. The mechanisms of oxide formation are explained by considering chemical thermodynamics and kinetics. The next step is to evaluate the tribological performance (wear, friction, lubrication regimes) of this SPS-processed material and compare its performance with conventional MoM products (cast and wrought). The SPS route offers significant advantages over the conventional cast and wrought routes used to prepare this alloy for orthopaedic applications.
INTRODUCTION
Osteochondral defects are still a challenge for the orthopaedic surgeon, since most of the current surgical techniques lead to fibrocartilage formation and poor subchondral regeneration, often associated to joint stiffness and/or pain.
Thinking of the ideal osteochondral graft from both the surgical an commercial point of view, it should be an off-the-shelf product; this is the research direction and the explanation for the new biomaterials recently proposed to repair osteochondral defect inducing an “in situ” cartilage regeneration starting from the time of the implantation into the defect site.
For the clinical pilot study we performed, a newly developed nanostructured biomimetic scaffold was used to treat chondral and osteochondral lesions of the knee; its safety and manageability, as much as the surgical procedure reproducibility and the clinical outcome, were evaluated in order to test its intrinsic potential without any cells colture aid.
MATERIALS AND METHODS
A new osteochondral scaffold was obtained by enucleating equine collagen type 1 fibrils with hydroxyapatite nanoparticles in 3 different layers with 3 different gradient ratios at physiological conditions.
30 patients (9F, 21M, mean age 29,3yy) affected by either chondral or osteochondral lesions of the knee (8 medial femoral condyles, 5 lateral femoral condyles, 12 patellae, 8 femoral throcleas) underwent the scaffold implantation from January to July 2007. The sizes of the lesions were in between 2 and 6 squared cm. All patients and their clinical outcome were analyzed prospectively at 6, 12, 24 and 36 months using the Cartilage standard Evaluation Form as proposed by ICRS and an high resolution MRI.
INTRODUCTION
The menisci play a fundamental biomechanical role in the knee and also help in the maintaining of the articular homeostasis; thus, either a lesion or the complete absence of the menisci can invalidate the physiological function of the knee causing important damages, even at long term. Unfortunately, meniscal tears are often found during the ordinary orthopaedic practice while the regenerative potential of this kind of tissue is very low and limited to its peripheral-vascularized part; this is why the majority of these common arthroscopic findings are not reparable and often the surgeon is almost forced to perform a partial, subtotal or even total meniscectomy, regardless of the well-known consequences of this kind of surgery.
MATERIALS AND METHODS
Recently a porous, biodegradable scaffold made of an aliphatic polyurethane (Actifit(tm),Orteq Ltd) has been developed for the arthroscopic treatment of partial and irreparable meniscal tears; thanks to its particular structure, this scaffold facilitates the regeneration of the removed meniscal part, preventing the potential cartilage damage due to its complete or partial lack.
We performed a prospective clinical study on 17 patients affected by a massive loss of meniscal substance either medial or lateral associated with intraarticular or global knee pain and/or swelling.
We analyzed the patient both clinically and by using the International Knee Document Committee's (IKDC) Subjective and Objective Knee Evaluation Form. We also assessed the sport activity resumption by comparing the Tegner score at the time of the very first visit with the presurgery and prelesional ones. Finally, we also organized a control MRI at 6 and 12 months after surgery.
Nowadays, initial fixation and relative movements of the tibial baseplate with respect to the bone are not a hot topic anymore. Most surgeons have already accepted cement fixation and don't aim for bone ingrowth anymore. This might change if the trend towards implants that offer always a deeper flexion persists. These implants tend to load the tibial baseplate more posteriorly during deep flexion potentially causing a higher risk of lift_off and thus loosening. The ideal concept pushing our team was the search for a design of either a stem or other fixation features able to hold the baseplate to the bone keeping the amount of bone that needs to be removed within acceptable limits.
The Profix tibial baseplate (Smith & Nephew) has a wide range of fixation techniques available. It can be cemented or used cementless and, in both cases, several stem designs are available. One of these is the so-called Omega stem. It has the advantage of being thin (in fact it is a stem and a chisel at the same time) but also stiff, withstanding bending loads due to its curvature in the transversal plane. It is also relatively short compared to other stems and it is thus bone-sparing and suitable for MIS.
Introduction
Radiostereometric Analysis (RSA) is an imaging method that is increasingly being utilized for monitoring fixation of orthopaedic implants in randomized clinical trials. Extensive RSA research has been conducted over the last 35+ years using standard clinical x-ray acquisition modalities that irradiate screen/film media or Computed Radiography (CR) plates. The precision of RSA can depend on a number of factors including modality image quality.
Objective
This study assesses the precision of RSA with a novel Digital Radiography (DR) system compared to a CR imaging system using different imaging techniques. Additionally, the study assesses the precision of locating beads embedded in a modified spine pedicle screw.
The clinical results of the cemented Exeter stem in primary hip surgery have been excellent. The Exeter ‘philosophy’ has also been extended into the treatment of displaced intracapsular hip fractures with ‘cemented bipolars’ and the Exeter Trauma Stem (Howmedica).
We have identified an increase in the number of periprosthetic fractures that we see around the Exeter stem. We have also identified a particular group of patients with comminuted fractures around ‘well fixed’ Exeter stems after primary hip surgery that present a particular difficult clinical problem.
Prior to fracture, the stems are not loose, the cement mantle remains sound and bone quality surrounding the reconstruction is good, i.e. classifying it as a Vancouver B1. However the comminuted nature of the fracture makes reduction and fixation with traditional methods difficult. Therefore in these particular circumstances it is often better to manage these as B2 or even B3 fractures, with distal bypass and uncemented reconstruction.
Over an eleven-year period since 1999, 185 patients have been admitted to Nottingham University Hospitals with a periprosthetic femoral fracture around a hip replacement. These patients were identified from a prospective database of all trauma patients admitted to the institution. Of these patients we have identified a cohort of 21 patients (11%) with a periprosthetic fracture around an Exeter polished stem. Hospital notes were independently reviewed and data retrieved. Outcome data was collected with end points of fracture union, re-revision surgery and death. Data was also collected on immediate and long term post-operative complications.
The mean age was 76 years at time of fracture, and 52% were male. The mean duration between primary index surgery and fracture was 18 months (median 11 months).
15 patients were classified as Vancouver B1, and six as B2 fractures. Of the B1 fractures, 14 underwent fixation and one was treated non-operatively. Of the B2 fractures, four were revised, one was revised and fixed using a plate, and one was fixed using a double-plating technique. Prior to fracture, none of the implants were deemed loose although one patient was under review of a stress fracture which subsequently displaced.
One patient died prior to fracture union. All the other patients subsequently went onto unite at a mean of 4 months. There were no deep infections, non- or malunions. No patient underwent further surgery. Dislocation occurred in one patient and a superficial wound infection occurred in one patient which responded to antibiotic treatment. Three other patients have subsequently died at seven, twelve and fifty-three months post fracture due to unrelated causes.
In our series of patients, in addition to the more standard fracture patterns, we have identified a very much more comminuted fracture. Indeed, we have described the appearance as if the tapered stem behaves like an axe, splitting the proximal femur as a consequence of a direct axial load. As a consequence of the injury, the cement mantle itself is severely disrupted. There is significant comminution and soft tissue stripping, calling into question the viability of the residual fragments. Treatment of this type of fracture using a combination of plates, screws and cables is unlikely to provide a sufficiently sound reconstruction. In our experience we believe these fractures around previously ‘well fixed’ Exeter stems should be treated as B2/B3 injuries.
We have identified 69 patients with Vancouver B1 periprosthetic fractures around stable femoral implants. Open reduction internal fixation is the recommended treatment; however recent studies have revealed high rates of nonunion. We have reviewed the fixation techniques utilized to treat these patients, and identified outcomes in relation to rates of union, further surgery and mortality.
Patients were identified from a prospective database of all trauma admissions at Nottingham University Hospitals from 1999 to 2010. Hospital notes were independently reviewed and data retrieved.
69 patients were identified. Mean age 77 years and 63% were female. 51 (74%) occurred around total hip replacements and 18 (26%) around hip hemiarthroplasty after a previous hip fracture.
Periprosthetic fracture occurred around an Exeter stem (n=18), Charnley (n=10), Austin Moore (n=15), other (n=6). 20 patients had undergone previous revision surgery. The mean time from index surgery to fracture was 58 months (median 24) around primary stems, and 48 months (median 22) around revision stems.
6 patients (9%) were treated non-operatively. Five of these had undisplaced fractures (all healed but one required revision due to loosening) and one was too unwell.
63 patients (91%) were treated by open reduction internal fixation. Of these, single plate fixation was performed in 40 cases (64%). In the vast majority of cases, lag screw fixation of the fracture with a long (>12 hole) pre-contoured 4.5mm locking plate was utilised with cables. Both locking and cortical screws were used to achieve stable fixation (Figure 1). A double plate technique was used in 16 cases (25%), where plates were placed perpendicularly to each other (laterally and anteriorly). Strut grafts were used in 13 cases (21%). 7 patients (11%) were treated with cables alone.
23 patients have subsequently died (33%). Two have been lost to follow up and three are awaiting union. There is a mean follow-up of 35 months.
Deep infection occurred in 4 cases (6%). Non-union occurred in four cases (6%). Two of these were infected and one was treated with cables alone. Malunion occurred in one case treated with cables. One patient had a dislocation and two superficial infections occurred.
Further surgery took place in 8 patients (12%). Three of the infected cases were revised and one underwent wound washout. The two other non-unions were revised. Three further revisions were performed: one for malunion, one for aseptic loosening (treated non-operatively) and another for a second periprosthetic fracture. Superficial wound washout was performed in one case.
Mortality was 10% at 3 months, 22% at 1 year and 47% at 3 years.
We have identified that union can be achieved in the majority of cases after periprosthetic fracture fixation. Cable fixation was associated with a high complication rate (7 cases: two requiring revision surgery: one nonunion, one malunion).
We recommend that Vancouver B1 periprosthetic fractures are treated with meticulous technique to achieve anatomical reduction and fracture compression using lag screw technique and plating. Further mechanical support can be provided through the use of a second plate, cables and/or strut grafts.
INTRODUCTION
Since July 2008 we are experimenting a new cup with iliac screw fixation, developed on the idea of Ring and Mc Minn. Iliac fixation is permitted by a polar screw of large diameter, coated by HA, which allows a compression to bone and a firm primary stability. Moreover it's possible to increase primary stability with further smaller peripherals screws. We present this new cup and report the preliminary results.
MATERIALS AND METHOD
Since July 2008 to April 2010, 51 cups were implanted. The diagnosis was aseptic loosening in 36 cases, septic loosening treated by two-stage revision in 7, hip congenital dislocation in 5, one case of post-traumatic osteoarthritis, one case of instability due to cup malposition and a case was an outcome of Girdlestone resection arthroplasty. Mean age was of 66 years (31-90).
Numerous investigators have described osteogenic differentiation of bone marrow stromal cells obtained from both murine and human sources over the past decade. The ease of access and large available quantity of adipose tissue, however, makes Adipose-Derived Stem Cells (ADSC) a far more practical alternative for clinical applications, such as operative treatment of non-unions and regeneration of critical bone defects. Therefore, the primary goal of this research endeavor is to achieve osteogenic differentiation of ADSC. Previous work has already demonstrated that bone morphogenetic protein receptor 1A (BMP receptor 1A) signaling is required for healing critical bone defects. Based on this evidence, we used a lentiviral vector to increase expression of BMP receptor 1A by our stem cell population in order to direct their differentiation into the osteoblastic lineage.
We harvested subcutaneous adipose tissue intraoperatively from consenting patients undergoing elective lipoplasty and panniculectomy procedures. The stromal vascular fraction was isolated from this tissue and further refined by passaging in selective media to yield a stable population of ADSC in primary culture. Both the identity and homogeneity of this stem cell population was confirmed using adipogenic induction media and differentiation cocktails. In addition, we subcloned an expression plasmid containing the BMP receptor 1A locus in tandem with green fluorescent protein (GFP) under the transcriptional control of a single promoter. This plasmid was packaged into a lentiviral vector to provide a reliable method of achieving both genomic integration and long-term expression of the BMP receptor 1A gene. Hence, transduction of ADSC using this vector resulted in overexpression of BMP receptor 1A by these multipotent cells. The GFP was then utilized as a reporter gene to screen and enrich the ADSC population for only those stem cells with a robust expression of BMP receptor 1A. The ADSC that overexpressed BMP receptor 1A were found to achieve osteogenic differentiation after 18 to 20 days of in vitro culture, as revealed by immunohistochemistry assays for osteocalcin. Osteogenic differentiation was further confirmed by alizarin red staining and quantitative PCR for alkaline phosphatase gene expression as a biomarker for the osteoblastic lineage.
Our results demonstrate that stem cells derived from the adipose tissue of a patient represent a viable means of culturing autologous osteoblasts in vitro for future implantation at the site of critical bone defects. This method of attaining osseous regeneration is intuitively appealing, given the minimal donor site morbidity associated with removing subcutaneous fat. By transducing the ADSC with a lentiviral vector, we have also collected further evidence implicating the critical importance of signaling mediated by the BMP receptor 1A during osteogenesis. Further tissue engineering studies are now in progress to evaluate the osteogenic differentiation potential of these stem cells under hydrostatic and fluid flow shearing mechanical loads.
MRI has been little utilised in the post-operative assessment of joint replacement due to the problem of artifact. With modern machines and sequencing, artifact can be minimised in small joints with titanium prostheses. Twenty four consecutive patients implanted with a Buechel-Pappas Total Ankle Replacement underwent MRI examination at an average of 583 days post surgery to determine its usefulness as an adjunct to x-ray and bone scan in assessing prosthetic integrity and the source of post-operative symptoms.
The purpose of the study was to evaluate the use of modified MRI techniques in the assessment of bone-implant interface, soft tissue changes, bone oedema and extent of osteolysis in setting of total ankle joint replacement and propose a descriptive classification to document the changes.
We found MRI was extremely useful in identifying abnormalities in structures apart from the prosthesis such as occult degeneration in the subtalar joint and ligament pathology. Despite the new techniques, artifact remains a problem when assessing the bone prosthesis interface although adjacent bone oedema is well seen.
MRI has a role in the identification of pathology in the tissues surrounding a TAJR especially with unexplained pain in an otherwise well functioning prosthesis. It's role in the assessment of prosthetic integrity remains qualitative but further work will be required to correlate MRI findings with clinical examination.
Introduction
Arthritic knees requiring total knee replacement may present with additional deformities located along the femur or tibia away from the articular region. These deformities may be congenital, developmental, associated with metabolic bone disease, or acquired as a result of malunited fractures or previous advocated for arthritic knee with ipsilateral extra-articular deformity.
Methods
We undertook retrospective study to evaluate the results of total knee arthroplasty in arthritic knee with extra-articular deformity in 26 knees (24 patients). Sixteen deformities were in tibia and ten deformities were in femur. All patients underwent total knee arthroplasty with intraarticular bone resection and soft tissue balancing.
OBJECTIVE
To evaluate the results of results of total knee replacement (TKA) in stiff and Ankylosed knees.
A retrospective study was done to evaluate the results of total knee arthroplasty performed on 110 knees in 69 patients with spontaneously Ankylosed knees. The reasons of ankylosis was previous infection (pyogenic and tuberculous), inflammatory arthritis (rheumatoid arthritis, Juvenile rheumatoid arthritis, ankylosing spondylitis) and post –traumatic. The age at operation ranged from 30 to 65 years (average 42.8 years). Preoperative arc of movement was between 0 degrees and 20 degrees (average, 14 degrees). The difficulties encountered in surgical exposure were managed by using various extensile exposure techniques. Quadriceps snip was used in all case to avoid patellar avulsion. Follow-up ranged from 5 to 17 years (average, 9 years). The average postoperative arc of movement at final follow-up was 75.8 degrees, with a significant average gain of 61 degrees at final follow up. The average preoperative Hospital for Special Surgery Knee Score was 60 which improved to 75 at the final follow up. The average extensor lag was 8 degrees (range 0- 20 degrees). Complications included skin edge necrosis (35%), pyogenic infection in 3 patients, and a quadriceps tendon rupture in 1 patient. 4 knees were revised on account of component loosening.
Conclusions
Total knee arthroplasty in Ankylosed knees does achieve correction of deformity with gain in range of motion leading to improved quality of life. Meticulous surgical technique is required to prevent complications. We believe that TKA in Ankylosed knees is a viable option.
INTRODUCTION
Use of a novel ligament gap balancing instrumentation system in total knee arthroplasty resulted in femoral component external rotation values which were higher on average, compared to measured resection systems. In one hundred twenty knees in 110 patients the external rotation averaged 6.9 degrees (+/− 2.8) and ranged from 0.6 to 12.8 degrees. The external rotation values in this study were 4° and 2° larger, respectively, than the typical 3° and 5° discrete values that are common to measured resection systems. The purpose of the present study was to determine the effect of these greater external rotation values for the femoral component on patellar tracking and flexion instability.
METHODS
One hundred twenty knees in 110 patients were consecutively enrolled by a single surgeon using the same implant across subjects. All patients underwent arthroplasty with tibial resection first and that set external rotation of the femoral component based upon use of a ligament gap balancing system. Following ligament tensioning/balancing, the femur was prepared. The accuracy of the ligament balancing system was assessed by reapplying equal tension to the ligaments using a tensioning bolt and torque wrench in flexion and extension after the bone resections had been made. The resulting flexion and extension gaps were then measured to determine rectangular shape and equality of the gaps. Postoperative Merchant views were obtained on all of the patients and patellar tracking was assessed and compared to 120 consecutive total knee arthroplasties previously performed by the same surgeon with the same implant using a measured resection system.
High tibial osteotomy is an efficient treatment for medial compartment osteoarthritis of the knee; its used for middle aged patients with high activity levels and can delay the need for total arthroplasty.
The results of total knee arthroplasty after failed high tibial osteotomy are controversies; several authors reported inferior outcomes, but others have concluded that tibial osteotomy doesn't bias following total arthroplasty. The aim of this study was to evaluate the results of failed high tibial osteotomy subsequently converted to total knee arthroplasty and compare the results to group of patients underwere primary arthroplasty; the authors evaluate some of technical problems that a previous high tibial osteotomy can generate, like scar tissue, patellar tendon shortening and changes of proximal tibial anatomy.
Methods
50 total knee arthroplasty performed after a previous closed wedge osteotomy were matched with 50 patients operated with a primary knee prosthesis for osteoarthritis. The time from a proximal tibial osteotomy to a prosthesis operation was in mean eight years.
Results
the Knee Society clinical and radiographic score system and W.O.M.A.C. evaluation were used to evaluate knees before surgery and at each follow up (average 5 years).
At an average of five years follow up, the clinical results of total knee arthroplasty after high tibial osteotomy were similar to those of primary knee prosthesis.
Objective
was to review the experience of the Rizzoli with megaprosthetic reconstruction of the extremities in musculoskeletal oncology.
Material and methods
Between April 1983 and December 2007, 1036 modular uncemented megaprostheses of the lower limbs were implanted in 605 males and 431 females: 160 KMFTR(r), 633 HMRS(r) prostheses, 68 HMRS(r) Rotating Hinge and 175 GMRS(r). Sites: distal femur 659, proximal tibia 198, proximal femur 145, total femur 25, distal femur and proximal tibia 9. Histology showed 612 osteosarcomas, 113 chondrosarcomas, 72 Ewing's sarcoma, 31 metastatic carcinomas, 89 GCT, 36 MFH,68 other diagnoses.
Between 1975 and 2006 at Rizzoli 344 reconstructions of the humerus using prosthetic devices (alone or in association with allografts) were performed: 289 MRS(r), 37 HMRS(r), 2 Osteobridge(r), 4 composite prostheses, 8 Coonrad-Morrey(r), 4 custom made prostheses. Sites of reconstruction were: proximal humerus 311, distal humerus 19, diaphysis 5, total humerus 9. Histology showed 146 osteosarcomas, 56 chondrosarcomas, 23 Ewing's sarcoma, 67 metastatic carcinomas, 14 GCT, 10 MFH, 28 other diagnoses.
Patients were followed periodically in the clinic. Information were obtained from clinical charts and imaging studies with special attention to major complications requiring revision surgery. Major prostheses-related complications were analysed and functional results evaluated according to the MSTS system. Univariate analysis by Kaplan-Meier actuarial curves was used for studying implant survival to major complications.
Objective
of this study was to analyse results of two stage revisions in infected megaprostheses in lower limb.
Material and methods
Between April 1983 and December 2007, 1036 modular uncemented megaprostheses were implanted in 605 males and 431 females with mean age 33.5 yrs: 160 KMFTR(r), 633 HMRS(r) prostheses, 68 HMRS(r) Rotating Hinge and 175 GMRS(r). Sites: distal femur 659, proximal tibia 198, proximal femur 145, total femur 25, distal femur and proximal tibia 9. Histology showed 612 osteosarcomas, 113 chondrosarcomas, 72 Ewing's sarcoma, 31 metastatic carcinomas, 89 GCT, 36 MFH,68 other diagnoses.
Infection occurred in 80 cases (7.7%) at mean time of 4 yrs (min 1 month, max 19 yrs) in 18 KMFTR(r), 47 HMRS(r), 5 HMRS(r) Rotating Hinge, 10 GMRS(r). Sites: 51 distal femurs, 21 proximal tibias, 6 proximal femurs, 1 total femur and 1 extrarticular knee resection. Most frequent bacteria causing infection were: Staphilococcus Epidermidis (39 cases), Staphilococcus Aureus (17) and Pseudomonas Aeruginosa (5). Infection occurred postoperatively within 4 weeks in 9 cases, early (within 6 months) in 12 cases, late (after 6 months) in 59 cases.
Usual surgical treatment was “two stage” (removal of implant, one or more cement spacers with antibiotics, new implant), with antibiotics according with coltures. One stage treatment was used for immediate postoperative infections, only since 1998.
Functional results after treatment of infection were assessed using the MSTS system.
Purpose
of this study is to analyze the results of a modular reconstructive tumor prosthesis for the lower limb (GMRS(r)) with a comparative statistical analysis of primary and secondary implants.
Material and methods
From October 2003 to September 2007 at Rizzoli 161 GMRS(r) prostheses were implanted, most after resection of osteosarcoma (94 cases, 58%). It is a modular system with a rotating hinge mechanism for the knee, cemented and uncemented stems, in titanium and chromium-cobalt-molybdenum, curved and straight-fluted, with or without hydroxyapatite coating. Moreover adaptors are available to revise HMRS(r) implants.
This series includes 88 males and 73 females ranging in age from 9 to 80 years. Sites of reconstruction were 109 distal femurs, 19 proximal femurs, 1 total femur and 32 proximal tibias. There were 149 oncologic and 12 non oncologic diagnoses, including 96 primary reconstructions and 65 revisions after failure of previous implant. A retrospective analysis of imaging and complications was performed and functional results assessed according to MSTS system. Statistical analysis with Kaplan-Meier curves was used to study implant survival.
Purpose
In revision hip surgery, Type IIIB femurs have presented the greatest historical challenge to achieving stable fixation and osseous integration. This study evaluated the intermediate term outcome of a modular, tapered, distal fixation revision femoral component used in a consecutive revision hip series with special attention to its performance in the defective Type IIIB femur.
Methods
Between February 2002 and January 2005, 51 consecutive revision hip arthroplasties were performed using modular, tapered, distal fixation femoral components. The femoral defects at the time of revision surgery were classified using a system previously described by Paprosky. The most recent radiographs were reviewed and clinic notes examined to assess femoral component stability.
The presentattion will focus on technical tips that make OrthoPilot Navigated Total knee replacement easier and faster. Navigation while providing accuracy and soft tissue balancing, does add time to the procedure and there is a learning curve to Navigation, The presentation will highlight steps where time is wasted and what can be done to speed up the procedure. Sources of error and steps to minimze errors will also be discussed. This will be presentation emphasizing techical tips and no research findings or data will be presented.
Introduction
Hip resurfacing is a bone sparing approach to treating arthritis in younger or more active patients. Accurate positioning of the femoral component in the hip resurfacing procedure is essential for the success of the operation [1-2]. An alignment guide assisting the operator in accurately positioning the resurfacing implant may increases the success rate of the operation. This study focuses on the effectiveness of a CT based resurfacing alignment guide, shown in Figure 1.
Materials and Methods
Four full fresh frozen human cadaveric specimens were CT scanned to reconstruct bone models of the femoral head/neck geometries with no cartilage included in the segmentation. Femoral head resurfacing alignment guides were then created through computer aided design (CAD) modeling using landmarks from the reconstructed bone models for proper seating. A total of 12 resurfacing alignment guides (3 for each specimen) were prepared.
After the exposure of the hip joints, the first two out of three resurfacing alignment guides were used to asses the fit, stability, and visual assessment of valgus and version alignments. The third resurfacing alignment guide for each specimen was placed on the femoral head/neck region and the guide wire was drilled into the femur. A fluoroscopy image was taken to assess and measure the valgus and version alignment. The acceptance criteria for valgus alignment, as shown in Figure 2, is set to be ±2.5° from a line parallel to the medial calcar of the femoral neck, Similarly, the acceptance criteria for the version alignment was set to be ±2.5° from a line passing through the neutral axis of the femoral neck.
Purpose
Proper positioning of the components of a knee prosthesis for obtaining post-operative knee joint alignment is vital to obtain good and long term performance of a knee replacement. Although the reasons for failure of knee arthroplasty have not been studied in depth, the few studies that have been published claim that as much as 25% of knee replacement failures are related to malpositioning or malalignment [x].
The use of patient-matched cutting blocks is a recent development in orthopaedics. In contrast to the standard cutting blocks, they are designed to fit the individual anatomy based on 3D medical images. Thus, landmarks and reference axes can be identified with higher accuracy and precision. Moreover, stable positioning of the blocks with respect to the defined axes is easier to achieve. Both may contribute to better alignment of the components.
The objective of this study was to check the accuracy of femoral component orientation in a cadaver study using specimen-matched cutting blocks in six specimens; first for a bi-compartmental replacement, and then for a tri-compartmental replacement in the same specimen.
Materials and Methods
Frames with infrared reflective spherical markers were fixed to six cadaveric femurs and helical CT scans were made. A bone surface reconstruction was created and the relevant landmarks for describing alignment were marked using 3D visualisation software (Mimics). The centres of the spherical markers were also determined. Based on the geometry of the articular surface and the position of the landmarks, custom-made cutting blocks were designed. One cutting block was prepared to guide implantation of a bi-compartmental device and another one to guide implantation of the femoral component of a total knee replacement.
The knee was opened and the custom-made cutting block for the bi-compartmental implant was seated onto the surface. The block was used to make the anterior cut, after which it was removed and replaced with the conventional cutting block using the same pinning holes to ensure the same axial rotational alignment. The other cuts were made using the conventional cutting block and the bi-compartmental femoral component was implanted. Afterwards, a similar procedure was used to make the extra cuts for the total knee component.
The position of the components with respect to the reflective markers was measured by locating three reference points and “painting” the articular surface with a wand with reflective markers. The position of all marker spheres was continuously recorded with four infrared cameras and Nexus software.
Introduction
Despite the theoretical advantages of mobile bearings for lateral unicompartmental knee replacement (UKR), the failure rate in the initial published series of the lateral Oxford UKR's was unacceptably high. The main cause of failure was early dislocation. In contrast, dislocations of bearings in medial UKR's are rare. The lateral compartment present a higher laxity in flexion than the medial. An adaptation of the lateral design by introducing a convex tibial component and biconcave bearing should tackle this difference in kinematics.
The risk of dislocation increased substantially if the lateral tibial joint line was elevated, quantified by the proximal tibial varus angle. This angle had a significant relationship to dislocation.
A recent kinematic study identified roughly 3 times as much posterior translation of the tibia during deep knee bend activities after lateral UKR compared to the normal knee, possibly also resulting in a higher incidence of bearing dislocation.
With the exception of dislocation, the overall early complication ratio in the initial published series of lateral Oxford UKR was also rather high compared to the last published series. Is there a learning curve?
Materials and Methods
Between January 2009 and April 2010, 16 domed lateral Oxford unicompartmental knee replacements were implanted by the senior author. The valgus deformity was in 2 cases not completely correctable. All femoral components were positioned anatomically. In no case the popliteus tendon was divided. A partial iliotibial band (ITB) release was done in 2 cases. The most common tracking deviation of the bearing peroperatively was a small lift off in deep flexion, seen in 6 cases.
Purpose of our study is to present the design rationale and the early clinical results for the Parva Stem, an innovative short hip stem. The Parva implant has been designed in order to address the bone sparing concept of a short stem able to achieve a good cervical and interthrocanteric primary fixation associated with a the reliable primary fixation the isthmus level.
The stem has been designed to address the larger possible variety of anatomical variations too. The stem therefore features innovative design concepts including the latest generation Modular Neck System, coupled with a revolutionary manufacturing process and surface engineering technology. This manufacturing process (Powder manufacturing Technology) and Ingrowth Surface (Ti-Por) will be also briefly discussed in the presentation.
Our early clinical results will be also presented (150 stem-one yr. maximum follow up will be presented) although they are not the main purpose of our study oriented more on the novel design and technological manufacturing advancement.
The feed-back we had so far with this state of the art implant is extremely encouraging. Of course further data collection and longer follow up will be needed in order to confirm these early promising results.
Trufit resorbable scaffolds, made of semiporous copolymer, are press-fit introduced in chondral defects of articular surfaces in order to promote filling and regeneration of damaged bone and cartilage tissues. In another previous work, we have presented our good and promising results obtanied at 1 yy follow-up. Then, we have had the chance to go on on follow-ups and check patients through second-look arthroscopies and serial MRI's: IKDC score showed 38 points improvement. WOMAC score showed statistically significant pain improvement in 89% of cases and function improvement in 86% of cases. Serial MRI's of the knees showed progressive incorporation of the synthetic plugs and no adverse inflammatory reaction. Second-look arthroscopies showed complete and flush fill of the defects and their resurfacing with hyaline-like tissue under different stages of maturation.
Recently, we have been able to check, clinically and by serial MRI's, the first patients operated 24 months ago. Despite the mantainance of clinical very good results, as showed by other authors, MRI images showed a delayed biologic process of incorporation of the plugs. This finding has not to be misinterpreted as an implant failure and the post-op rehabilitation has to be continued in order to give regenerating cartilage time to complete the maturation process.
Total joint arthroplasty is a safe and effective procedure as an end-stage treatment for arthritis. In the case of hip replacement mean patient age has decreased from sixty-eight to sixty-five years over the past eight years, raising concerns over implant longevity and the complications that occur in association with revision surgery.
The dominant mode of failure of total joint replacements is aseptic loosening, which in many cases is caused by the reaction of bone to the presence of implant debris. In an attempt to increase implant longevity, bearing surfaces that minimize the volume of debris generated from the articular surface are being developed. Ultra- high molecular weight polyethylene, which has been the mainstay of arthroplasty, changing the material with which the polyethylene articulates has also been addressed in an effort to further improve wear characteristics.
Oxinium is the brand family name of a material used for replacement joints manufactured by the reconstructive orthopedic surgery division of medical devices company Smith & nephew. It consists of a Zirconium alley metal substrate that transitions into a ceramic Zirconium oxide outer surface. The ceramic surface is extremely abrasion resistant compared to traditional metal implants such as cobalt chromium. It also has a lower coefficient of friction against ultra-high molecular weight polyethylene(UHMWPE), The typical counter face material used in total joint replacements.
These two factors likely contribute to the significantly lower UHMWPE wear rates observed in simulator testing.
Reducing UHMWPE wear is thought to decrease the risk of implant failure due to osteolysis. All ceramic material can have a similar effect in reducing wear, but are brittle and difficult to manufacture. The metal substrate of oxinium implants makes component easier to manufacture and gives them greater toughness(a combination of strength and ductility). In essence, this technology combines the abrasion resistance and low friction of a ceramic with the workability and toughness of a metal.
Background
The current literature tends to suggest that all the different approaches used for Knee Arthroplasty give similar results. The literature also cautions that the MINI quadriceps sparing approaches are to be utilized in very select cases as they are difficult to perform, take longer time, have a greater intra-op complication rate and are associated with a higher number of component malpositioning. Despite these warnings of the literature, the author has been impressed by the physiological nature of the subvastus approach for knee arthrotomy and the author has used this approach exclusively for all Knee arthroplasties in the last 4 years. All primary Knee Arthroplasties have been performed through the mini-subvastus approach, utilizing the principle of a mobile window, irrespective of the degree of pre-operative deformity, obesity, range of motion or previous surgery. All revision Knee Arthroplasties have also been performed through the subvastus approach. All the surgeries have been performed in the private sector in a highly competitive environment with the patient having easy access to various other high volume surgeons performing arthroplasties through a more standard approach.
Aim
To define the place of the subvastus approach in Knee arthroplasty on the basis of surgical experience gained after 1350 consecutive surgeries
Background Computer navigation is increasingly being recognized as a valuable tool in restoring the mechanical axis post TKR. Its use is as yet not universal due to the costs involved, its availability and the fact that it can be cumbersome and time consuming to use. Additionally it requires the insertion of Schanz pins in the femur as well as the tibia which can be a matter of concern as regards stress fracture and infection. However, it is able to reliably locate the center of the femoral head which is an elusive landmark in the standard method. The center of the ankle involves registration for the medial and lateral malleoli which are subcutaneous and easily palpable. We decided to navigate only the distal femoral cut with a specialized navigation unit called Articular Surface Mounted navigation which does not require the insertion of additional pins through the femur or the tibia. We purposely did not use navigation for the rest of the bony cuts as all the other landmarks i.e. femoral epicondyles, tibial malleoli, and tuberosity etc are all easily palpable. This dramatically reduced the surgical time and increased its user friendliness. We are presenting our results.
Aim
To analyse the radiographic results obtained with selective femoral navigation and compare with standard navigational results from the literature Non-navigated Knees form personal series.
Materials and Methods
We have utilized the ASM navigation for distal femoral cut in 112 knees and obtained long X-rays (scanograms) and routine knee X-rays (AP, Lateral and skyline) to study the mechanical axis and component positioning. We measured the mechanical axis deviation, femoral and tibial angle on AP and lateral films and patellar tilt or subluxation on post-operative X-rays by a digital imaging programme called Image–J. (As suggested by the Knee Society roentgenographic Score). We have compared our results with other navigated series from literature and our own series of non-navigated knees. (113 knees) We also noted the surgical time to perform the operation and the occurrence of any complications.
Computer assisted total knee arthroplasty has been demonstrated to provide reproducible limb mechanical alignment within three degrees from the neutral mechanical axis. However, restoring proper implant and extremity alignment remains a significant challenge with proximal tibial deficiencies. In this prospective study, we describe the use of computer navigation to quantify the amount of bone loss on the medial or lateral tibial plateau and the use of this data to assess the need for augmentation with metallic tibial wedges.
In this study, we demonstrate that CAS TKR in patients with significant tibial deformities can accurately measure severe tibial deformities, predict tibial augment thickness, and provide excellent mechanical alignment and restore the joint line without excessive bony resection, repeated osteotomies, and repeated augment trialing.
There is still want of evidence in the current literature of any significant improvement in clinical outcome when comparing computer-assisted total knee arthroplasty (CA-TKA) with conventional implantation. Analysis of alignment and of component orientation have shown both significant and non-significant differences between the two methods. Not much work has been reported on clinical evidence of stability of the joint.
We compared computer-assisted and conventional surgery for TKA at 5.4 years follow-up for patients with varus osteoarthritic knees with deformity of more than 15∗. Our goal was to assess clinical outcome, stability and restoration of normal limb alignment.
We used CT and Cine video X ray techniques to analysize our results in Computer navigated and conventional TKRs. A three dimentional CT scan of the whole extremity was performed and evaluation was done in three planes; saggital, coronal and transverse views. CT scan was done between 10 to 14 days postoperative. Mean deviations in the mechanical axis, femoral and tibial plateau angles, and in transverse view, the trans-epicondylar axis vs posterior condylar axis were measured. The prospective randomized study comprised of 98 patients with surgery done on knees, one side navigated and other side conventional. Mean deviation in the mechanical axis was 2.2∗ in conventional knees and 1.8∗ in navigated knees. In 5 % of cases retinacular release was needed and CT analysis showed TEA in deviation of more than 2 ∗ in these cases. We analysed intraoperative data (surgical time and intraoperative complications), postoperative complications, lower limb alignment, radiographic complication on X-ray imaging, and clinical outcome throughknee and function score, range of motion and joint stability.
Our results showed that CAS had greater consistency and accuracy in implant placement and stability of joint in full extension and 90∗ flexion. In the coronal view, 93.3% in the CAS group had better outcomes compared with EM (73.4%). In the sagittal axis, 90.0% CAS also had better outcomes compared with EM (63.3%). Computer-navigated total knee arthroplasty helps increase accuracy and reduce “outliers” for implant placement.
Introduction
Melorheostosis is a rare bone dysplasia characterized by its classic radiographic appearance resembling dripping candle wax. The condition was originally described by Leri and Joanny in 1922. Its etiology is not fully known and treatment in most instances has been symptomatic. There are nearly 350 reported cases on melorheostosis, joint replacement has been successfully attempted in the shoulder and knee joint. We describe a case of severe melorheostosis affecting the left hip causing secondary osteo-arthritis, which was treated with a total hip replacement (THR). To the best of our knowledge this is the first reported case of its kind in the World literature.
Case history
A 52-year-old male of Indian origin with known melorheostosis of the left leg for over 30 years, presented with symptoms suggestive of severe osteo-arthritis of the left hip. Previously he had been treated for melorheostosis of the knee joint (fig 1a & 1b) with excisions and decompression of the medial femoral condyle. His left hip became more painful over the last few years. He had a fixed flexion deformity of 20° of the hip, severe muscle wasting and the affected leg was 3 cm longer than the right leg. Radiographs (fig 2a & 2b) confirmed the presence of sclerotic new bone in the acetabulum eroding the femoral head. He had the classical dripping candle wax appearance along the medial border of the neck and shaft of the femur. He underwent a THR using a Corail-Pinnacle un-cemented prosthesis using ceramic on polyethylene bearing surfaces (fig 3a & 3b). Post operatively he made a quick recovery and there was a marked improvement in his symptoms and functional outcome scores at 6 weeks.
INTRODUCTION
The purpose of this study was to determine the rate of complications and re-operations after operative treatment of peri-prosthetic femur fractures sustained within 90 days following primary total hip arthroplasty (THA).
METHODS
4,433 patients (5,196 consecutive primary THAs) over 10 years at a single institution were retrospectively reviewed. Thirty-five (0.67%) peri-prosthetic fractures that were treated operatively in 32 patients were identified and classified using the Vancouver Classification. There were 9 patients with a type Ag fracture, 2 patients with a type B1 fracture, 17 patients with a type B2 fracture, 1 patient with a type B3 fracture, and 3 patients with a concomitant type Ag and B2 fracture. Eleven (34%) patients were treated with isolated ORIF: greater trochanter (9) or femoral shaft (2). Twenty-one (66%) were treated with femoral revision combined with (14) or without (7) attempted fracture fragment reduction; a diaphseal engaging stem was utilized in all revisions. One patient was lost to follow-up leaving 31 patients for evaluation
INTRODUCTION
Total hip arthroplasty (THA) is not commonly performed in young patients. However, markedly advanced hip disease can cause disabling end-stage arthritis, and THA may be the only available option for pain relief and restoration of function. We report our experience with modern alternative bearing THA in patients younger than 21 years.
METHODS
Twenty-one consecutive primary THAs were performed in 18 patients. Pre- and post-operative Harris Hip Scores (HHS) and any postoperative complications were recorded. Radiographs were reviewed for evidence of premature component loosening. Mean patient age at operation was 18 years (range, 13-20). There were 14 females (78%) and 4 males (22%). Nine patients (50%) were Caucasian, 8 (44%) were African-American, and 1 (6%) was Asian. Average follow-up was 45 months (range, 16-85). All patients failed conservative treatment; 15 patients had prior core decompression and bone grafting. Underlying etiology was chemotherapy induced osteonecrosis (7, 33%), steroid induced osteonecrosis (6, 29%), sickle cell disease (5, 24%), and chronic dislocation (3, 14%); 1 patient underwent THA for fracture of a previous ceramic bearing, 1 patient had a slipped capital femoral epiphysis, and 1 patient had idiopathic joint destruction. Components implanted were ceramic/ceramic (14, 67%), metal/highly cross-linked polyethylene (6, 29%), and metal/metal surface replacement (1, 5%).
The combination of obesity and malalignment may result in increased revision rates following total knee arthroplasty (TKA). The purpose of this retrospective matched-pair study was to compare the accuracy of limb and component alignment after TKA using conventional versus computer-assisted technique in obese patients. Radiographic data regarding limb alignment, coronal and sagittal component alignment of 72 conventional TKAs (52 patients) were compared with data of a matched group of 72 computer-assisted TKAs. All procedures were performed by a single surgeon, using a single approach and a cruciate-substituting design.
The mean postoperative limb alignment in the conventional group was 177.2° ± 2.5° compared to 179.3°± 1° in the computer-assisted group (p=0.0001). The coronal and sagittal alignment of both femoral and tibial components in the computer-assisted group was significantly accurate compared to the conventional group. In the conventional group, 40.2% of limbs (29 out of 72) had a postoperative HKA angle > ±3° from the neutral compared to 1.3% of the limbs (1 out of 72) in the computer-assisted group (p=0.0001).
Computer-assisted total knee arthroplasty performed in obese patients showed excellent limb and component alignment with very few outliers when compared to conventional total knee arthroplasty. Obesity is an appropriate indication for the use of computer navigation during TKA where use of conventional techniques may result in significant limb and component malalignment.
Excessive under correction of varus deformity may lead to early failure and overcorrection may cause progressive degeneration of the lateral compartment following medial unicompartmental knee arthroplasty (UKA). However, what influences the postoperative limb alignment in UKA is still not clear. This study aimed to evaluate postoperative limb alignment in minimally-invasive Oxford medial UKAs and the influence of factors such as preoperative limb alignment, insert thickness, age, BMI, gender and surgeon's experience on postoperative limb alignment.
Clinical and radiographic data of 122 consecutive minimally-invasive Oxford phase 3 medial unicompartmental knee arthroplasties (UKAs) performed in 109 patients by a single surgeon was analysed. Ninety-four limbs had a preoperative hip-knee-ankle (HKA) angle between 170°-180° and 28 limbs (23%) had a preoperative hip-knee-ankle (HKA) angle <170°. The mean preoperative HKA angle of 172.6±3.1° changed to 177.1±2.8° postoperatively. For a surgical goal of achieving 3° varus limb alignment (HKA angle=177°) postoperatively, 25% of limbs had an HKA angle >3° of 177° and 11% of limbs were left overcorrected (>180°). Preoperative HKA angle had a strong correlation (r=0.53) with postoperative HKA angle whereas insert thickness, age, BMI, gender and surgeon's experience had no influence on the postoperative limb alignment.
Minimally invasive Oxford phase 3 UKA can restore the limb alignment within acceptable limits in majority of cases. Preoperative limb alignment may be the only factor which influences postoperative alignment in minimally-invasive Oxford medial UKAs. Although the degree of correction achieved postoperatively from the preoperative deformity was greater in limbs with more severe preoperative varus deformity, these knees tend to remain in more varus or under corrected postoperatively. Overcorrection was more in knees with lesser preoperative deformity. Hence enough bone may need to be resected from the tibia in knees with lesser preoperative deformity to avoid overcorrection whereas limbs with large preoperative varus deformities may remain under corrected.
Background and Objective
In industrialized societies, the prevalence of radicular low back pain has exploded in recent years. Lumbar disc prolaps, protrusion, or extrusion account for less than 5% of all low back problems, but are the most common causes of nerve root pain and surgical interventions. The primary rationale for any form of surgery for disc prolaps is to relieve nerve root irritation or compression due to herniated disc material. The primary modality of surgical treatment continues to be either open or microdiscectomy, but several alternative techniques including
Nucleoplasty
It provokes ablation of the nucleus of the disk by a controlled thermal effect produced by radiofrequency. Nucleoplasty is minimally invasive treatment aimed at removing nuclear material and lowering intradiscal pressure and decompressing through coblation needle inserted percutaneously into the nucleus of intervertebral discs. This paper will show a 3 years experience with 110 cases with lumbar radicular pain secondary to a disc protrusion that underwent Nucleoplasty as their secondary therapy.
Purpose
In an effort to increase the durability of cemented total hip arthroplasties (THA), femoral stems were precoated using polymethlymethacrylate (PMMA). One such design is Harris precoat plus and centralign design (Zimmer, Warsaw, Indiana). The reports on these particular designs are variable, ranging from good survival to early failures, studied over short to medium term. Early failures have been attributed, most of the time to debonding at cement-bone interface. In view of lack of long term and variable results, we reviewed the results of primary hybrid THA performed during October 1990 to December 1995, using a PMMA coated, cemented femoral prosthesis and contemporary cementing techniques.
Materials and Methods
121 patients (136 hips) underwent primary THA using one of the precoated femoral stems during the study period. Thirty-five patients (36 hips) died and 23 patients (23 hips) were lost to follow-up due to some reasons. Two hips (2 patients) were revised for postoperative infection and hence, not included in study. Collectively, 75 hips (61 patients) were available for clinical and radiological reviews until the last follow-up, with an average follow-up period of 15.5 years (range, 14 to 18.3 years). The average age of the patients at the time of the index surgery was 53.6 years (range, 24 to 82 years). There were 43 males (55 hips) and 18 females (20 hips). Acetabular components used in these 75 hips were Harris Galante porous (HGP) cups in 69 hips and CLS Expansion cup (Protek, AG, Bern) in six hips. The mean age of 61 patients (75 hips) who were available for latest follow-up at December 2009, was 46 years (range, 22-65 years). Third generation cementing techniques and distal cement plug but no centralizer was used in all cases. All surgeries were performed by same surgeon at a single institute.
INTRODUCTION
Unicompartmental knee arthroplasty (UKA) has been shown to have many benefits over conventional Total Knee Arthroplasty (TKA), but has also been shown to be technically difficult. In fact, technical error is the most common cause of premature failure in UKA. Bicompartmental arthroplasty (BKA) has the potential to perform like TKA with the benefits of UKA. We describe the initial experience with customized alignment guides and implants for UKA and BKA, manufactured based upon preoperative CT scan.
MATERIALS AND METHODS
Twenty three implants in 19 patients were implanted and followed for a minimum of three months postoperatively. Knee society scores and SF-12 scores were collected preoperatively and postoperatively. Radiographs were analyzed with image analysis software for malposition and loosening.
INTRODUCTION
we have previously reported that bone preparation is quite precise and accurate relative to a preoperative plan when using a robotic arm assisted technique for UKA. However, in that same study, we found a large variation between intended and final tibial implant position, presumably occuring during cement curing. In this study, we reviewed a subsequent cohort of patients in which the tibial and femoral components were cemented individually with ongoing evaluation of tibial component position during cement curing.
METHODS AND MATERIALS
Group 1 comprised the simultaneous cementing techniquegroup of patients, previously reported on, although their x-rays were re-analyzed. Group 2 consisted of the individual cementing technique cohort. All implants were identical, specifically a flat, inlay all-polyethylene tibial component. Postoperative x-rays from each cohort of patients were evaluated using image analysis software. Statistical evaluation was performed.
Negative remodelling of the femoral cortex in the form of calcar resorption due to stress-shielding, and femoral cortical hypertrophy at the level of the tip of the implant due to distal load transfer, is frequenly noted following cemented total hip replacement, most commonly with composite beam implants, but also with polished double tapered components.
The C-stem polished femoral component was designed with a third taper running from lateral to medial across and along the entire length of the implant, with the aim of achieving more proximal and therefore more natural loading of the femur. The implant is designed to subside within the femoral cement mantle utilising the cement property of creep, generating hoop stresses, which are transferred more proximally to the femoral bone, starting at the level of the medial calcar. The intention is to load the proximal femur minimising stress-shielding and calcar resorption, as well as reducing distal load transfer as signified by the lack of distal femoral cortical hypertrophy.
We present the results of a consecutive series of 500 total hip replacements using C-stem femoral components, performed between March 2000 and December 2005 at a single institution. Data was collected prospectively and all patients remain under annual follow-up by a Specialist Arthroplasty Practitioner. The operations were performed using a standard surgical technique with third generation cementing using Palacos-R antibiotic loaded cement.
500 arthroplasties were performed on 455 patients with an average age at the time of surgery of 68.3 years (23-92). There were 282 (62%) female and 173 (38%) male patients with osteoarthritis being the predominant diagnosis. 77 patients have died (73 hips) and the average duration of follow-up for the entire series is 81 months (52-124).
Only 2 femoral implants have been revised - one for deep sepsis and the other as part of a revision procedure for a loose acetabulum, although the femoral component itself was not loose. One implant is currently loose following a periprosthetic fracture treated by internal fixation, but none of the remaining implants demonstrates any progressive radiolucencies in any Gruen zones or any features suggestive of current or future loosening. Calcar rounding has been observed, but there have been no cases with obvious loss of calcar height and no cases of distal femoral cortical hypertrophy.
The C-stem femoral component has therefore performed well in clinical practice and the objective of eradicating negative bone remodelling has been achieved. The study is ongoing.
Introduction
Rivaroxaban is the first licensed oral direct inhibitor of factor Xa. Recent studies from the RECORD trials suggest rivaroxaban has superior efficacy compared to enoxaparin in preventing venous thromboembolism (VTE) with no significant increase in the major bleeding risk. Concerns remain regarding the incidence of minor bleeding, consequent delayed wound healing and subsequent risk of infection. The aim of this observational study was to assess the incidence of post-operative complications in patients receiving either rivaroxaban or enoxaparin thromboprophylaxis following elective hip and knee arthroplasty.
Methods
258 patients undergoing elective total hip or knee arthroplasty within one NHS Trust were included. 202 subjects (mean age 70.7 years ± 10.0, 43% male) received a daily dose of 10mg of oral rivaroxaban and 56 (mean age 70.9 years ± 9.8, 39% male) had a daily subcutaneous injection of 40 mg of enoxaparin as thromboprophylaxis. Endpoints included VTE (deep vein thrombosis and pulmonary embolism), haemorrhagic wound complications, hospital re-admission, requirement for blood transfusion, minor and major bleeding and death.
Manual postoperative CT calculation of anteversion and inclination of the acetabular cup can be inaccurate and depends on the observer's experience. The aim of this study is to describe and present a validation of a new CT-image-based dedicate software (EGIT) for calculation of the acetabular component placement.
The software principle is based on a three-dimensional reconstruction of a patient's bones from anatomical data collected postoperatively on the patient's CT scan.
15 Patient to be operated for THR were enrolled in this study. All patients were evaluated with post operative CT-scan. Measurement of Cup positioning were performed with two different methods: a manual method, performed by an expert radiologist, and a software CT image based method. Statistical analysis was performed with Intraclass Correlation Coefficent to asses interobserver and intraobserver reliability. A paired T-test was used to detect differences between manual and software methods.
The Intraclass Correlation Coefficient was excellent for both the intraobserver and interobserver reliability. As expected the ICC is higher in the interobserver case.
A mean cup anteversion of 14.2 (S.D. ±6.9), mean inclination of 44.2 (S.D.± 5.8) are detected with EGIT by the expert surgeon; Mean Cup anteversion of 13.6 (S.D. ± 5.11), mean inclination of 43.3 (S.D.± 5.1) are detected with manual method by expert radiologist. No statistical difference have been found (P> 0.05).
The EGIT software seems to be an easy, accurate and reproducible method to calculate acetabular cup positioning using standard post-operative CT scan in THA.
Postoperative sepsis is a costly and potentially devastating problem in total joint arthroplasty. Airborne bacteria and other viable microorganisms shed from surgical staff are a source of deep prosthetic infection, and the density of airborne bacteria is correlated with the rate of postoperative joint sepsis in total joint arthroplasty surgery. Previous studies have also reported a positive relationship between the density of nonviable airborne particulate and viable CFU counts, both airborne and in the surgical wound, during surgery. The purpose of this study was to determine the extent to which a system that delivers a small field of local, directed HEPA-filtered air flow over the surgical field reduces airborne particulate and airborne bacteria during total hip arthroplasty. A minimum of 8 subjects per group provided 80% power (a = 0.05) to detect a =75% difference in bacterial density between groups. All patients who consented to undergo primary total hip arthroplasty were eligible. Thirty-six patients were prospectively randomized into three groups: directed air flow, air flow system present but turned off (sham), and control (standard) conditions. Airborne particulate and bacteria were continuously collected in consecutive 10 minute intervals within 5 cm of the surgical wound using an air sampling device. Data were analyzed using a generalized linear model for repeated measures. Particulate counts and bacterial density at the surgical site were 80% lower on average in the directed air flow group compared to the other two groups (p<0.001) (Figure 1). Density of particulate >10 μm in diameter was strongly related to bacterial density at the surgical site (p<0.001), as was staff count (p<0.001) and bacterial density at a control site that was remote from the surgical field (p<0.001). The directed air flow system's effectiveness in reducing bacteria appears to be related to its ability to reduce particulate that may carry and allow proliferation of bacteria. The directed air flow system is relatively simple to use and does not appear to hinder the function of the surgeon or operating room staff, impede access to the surgical site, or interfere with the surgical procedure. The directed air flow system can be used in any operating room environment to provide clean air equivalent to a properly-used, well-functioning laminar air flow system. The directed air flow system was effective in reducing airborne particulate and bacteria in the surgical field during total hip arthroplasty.
CASN is generally good at bone morphing and sizing, assisting with component orientation, gap balancing and providing reasonably accurate alignments of limb and components alike. However, such routine navigation technique fails to use the full potential of the registered information. Current technique provides reasonable static stability information in the coronal plane, but with axial and sagittal planes less well considered. A more dynamic approach seems to be necessary to define ‘potential envelopes of motion’, seeming to be the best possible way in which CASN will finally show fundamental improvements over ‘conventional’ technique.
Enhanced dynamic assessment using an upgraded CASN system (Brainlab) is now capable of improved ROM analysis and contact point observations. This consists of storing dynamic information including a) epicondylar axis motion, b) valgus and varus alignments, c) antero-posterior shifts, as well as d) flexion and extension gaps. Tracking values for both tibiofemoral and patellofemoral motion can also be obtained after performing registration of the prosthetic trochlea.
Observations can be made using a set of standardised dynamic tests. Firstly, the lower leg can be placed in neutral alignment and the knee put through a flexion-extension cycle. Secondly the test can be repeated but with the lower leg being placed into varus and internal rotation. The third test can be performed with the lower leg in valgus and external rotation. Also a new passive technique of ‘Drop and Push Testing’ into a) flexion and b) extension is giving new information which may prove useful a) in terms of over-stuffing of the extensor mechanism and tightness of flexion gap and b) provision of hyperextension to assist gait. Upgraded software prompts can improve workflows to facilitate optimisation of joint dynamics.
Twenty total knee arthroplasties have been studied using these techniques with particular reference to the patterns of instability found. Marked intra-operative variation in the stability characteristics of the trial implanted joints has been quantified before corrections have been made and final assessments performed. These corrections have also been analysed in terms of change in antero-posterior translations, rotations and contact points. Edge loading and excessive paradoxical motions have been identified and corrective measures carried out, thereby improving PCL tensioning. Component rotations, tibial slope angles, insert thicknesses and femoral sizing have had to be adjusted to optimise range of motion and stability characteristics. Certain cases have been identified where use of more congruent or even stabilised components was considered necessary. Patellar tracking has also been observed during such dynamic tests and appropriate adjustments made to components and soft tissue balancing.
In summary, this study has enabled intra-operative observation, classification and quantification of patterns of instability in 6 degrees of freedom using simple stress tests followed by appropriate adjustments.
Degenerate chondral surfaces can be assessed in many ways, but arthroscopy is often performed without proper categorisation, mapping, zoning or sizing of lesions. Progression of disease in un-resurfaced compartments is well-recognised to occur, but is only one of several failure mechanism in partial knee replacement.
A validated ‘Functional Zone’ mapping method was used to document articular surface damage in 250 sequential cases of knee arthroscopy in patients over the age of 40. Size, shape, location and severity of each chondral lesion were noted using the Outerbridge classification. Analysis determined rates of involvement of particular compartments and assessed potential for partial replacement or local treatment and also to consider the risk of future progression. Radiographs including antero-posterior standing, postero-anterior flexion views (Rosenberg), lateral and skyline views were graded (Kellgren and Lawrence) and compared with the arthroscopic findings.
Our results showed that out of the 210 knees with Grade 3 or greater damage 13.3% of knees showed ‘isolated’ medial disease of Outerbridge Grade 3 or worse. Isolated lateral disease was noted in 1.4%, patello-femoral disease in 24.3%, bi-compartmental (Medial/PFJ) disease in 30.9% with tibio-femoral and tri-compartmental disease seen in 15.2%. The combination of lateral and patello-femoral disease was seen in 14.8%. Provided that Grade 1 and 2 changes (which were found in other compartments in high percentages) were ignored and ACL status considered, this information seemed to indicate that at the time these procedures were performed, 13.3% of cases were suitable for a medial uni-compartmental device, with sub-analysis of lesion sizes indicating that 17 out of 28 cases (60.7%) were suitable for a localised resurfacing. Lateral uni-compartmental replacement seemed suitable for only 1.4%, patello-femoral replacement in 24.3%, bi-compartmental in 30.9% and total knee replacement in 30%. The mean age for partial resurfacing was 53years and 59 years for total joint replacements.
Radiological analysis found that the antero-posterior standing views had only 66% sensitivity and 73% specificity for the presence of Grade 3 changes or worse in the medial compartment in comparison with Rosenberg views having a sensitivity of 73% and a specificity of 83%. Skyline views had a sensitivity of 56% and 100% specificity.
This study indicates that a large proportion of cases may be suited to local and limited resurfacing. Cases suitable for Patello-femoral and Bi-compartmental replacements were very common, but with the patella-femoral joint's tendency to be more forgiving in terms of symptoms, meaning that indications for uni-compartmental replacement might well be much higher than the arthroscopic findings suggested. On the other hand, the presence of high levels of Grade 1 and 2 changes in other compartments seems to indicate a need for caution particularly in younger patients. This study also indicates a need for better methods of assessing local cartilage health such as enhanced MRI scanning or spectroscopy.
Several options for high demand/high activity patients for bearings in THA exist. Each of them faces certain known and unknown risks of failure. There is a remarked trend to bigger diameter heads to reduce the incidence of dislocation for such patients. While combinations with hard-on-hard bearings have been used in such incidences, a Polyethylene (PE) option is desirable due to its less sensitivity to edge loading and price.
A highly crosslinked sequentially annealed PE of the 3rd generation was prepared by sequentially crosslinking with appropriate annealing steps with a cumulative dose of 90 kGy and subsequent gas plasma sterilization. The structure of this material was determined using TEM, DSC and SAXS. Free radicals and oxidation was determined by ESR and IR spectroscopy. Mechanical evaluation in the unaged and aged condition were performed by quasi-static, dynamic and functional dynamic tests in comparison with negative controls. Wear testing was performed by ball-on-plate tests and hip joint simulators. PE inserts of various internal diameters up to 44mm and thicknesses of 4-8mm in comparison with a historic inert gas irradiation sterilized PE as negative control. These tests have been carried out at 3 institutions using different set-up and protocols. To look at worst case scenarios the simulator testing was done in an impingement mode and fatigue tests of the thinnest components where performed in 2 different fatigue set-ups up to 10 million cycles.
The structure and crystallinity of the sequentially crosslinked PE were comparable to the controls. The radical concentration was reduced by more than 95% due to the sequential process employed and consequently the oxidation level after artificially aging remained at the level of untreated PE. 5 year storage data confirmed the stability of this polymer. All mechanical testing revealed the maintenance of the properties at the same level as the controls. The screening wear test revealed that the high sliding stress used in this set-up had no effect on the sequentially crosslinked PE even when aged, while the controls showed fatigue wear after a short time of testing.
The decrease in volumetric wear compared to a negative control (28 mm head size) was on average 90% in volumetric independent of the head size and thickness of the PE liner. This result was confirmed by the studies at 2 other institutions with a wear reduction of 86 and 95% respectively. Impingement increased the wear rate marginally, without causing any fractures or failures of the components. The analysis of the wear particles from the simulator studies showed a marked decrease in number with close similarity in appearance and morphology to that from the control tests. Fatigue testing even in a luxation model showed no negative effect on the impact on the rim after 10 million cycles also with the thinnest components.
Highly crosslinked, sequentially annealed PE from the perspective of tribological and fatigue testing can be used safely even in impingement and luxation situations. Other factors in the clinical usage of thin liners may play a role and need to be investigated further.
Aims
Recently, total knee arthroplasty (TKA) has been generalized as an operation that achieves excellent clinical results. However, younger and Asian patients require even greater implant longevity and functional performance. We hypothesized a novel posterior cruciate-retaining TKA design that restores the anatomical jointline in both sagittal and coronal planes, maintains the femoral posterior condylar offset, and provides low contact stress would provide enhanced patient function with the potential for greater implant longevity.
Methods
The novel TKA design was created based on geometry determined from anatomic specimens, 3-degree step of femorotibial jointline was incorporated in the TKA design for Asian. The novel TKA has an asymmetrical design between the medial and lateral femoral condyle, the medial femoral condyle designed to be 3 degrees larger than the lateral femoral condyle. It refined using finite element analyses (FEA) to minimize peak contact stresses. The alignment evaluation after TKA was performed using using bidirectional CR and CT images. Femorotibial-angle (FTA), the position of the femoral component relative to the 3D mechanical axis, and the rotational alignment of the femoral component relative to the PC line were evaluated before and after TKA to identify changes in the femoral condylar shape. The kinematic evaluation after TKA was performed using a 3D-to-2D model registration technique. Single-plane fluoroscopic imaging was used to record and quantify the motions of knees during a stair-step activity. The contact points between the tibiofemoral motions and the tibial rotational angle were evaluated.
Introduction
Up to 2% of total hip arthroplasties (THA) are still complicated by infection. This leads to dissatisfied patients with poor function, and has far-reaching social and economic consequences. The challenge in these cases is the eradication of infection, the restoration of full function and the prevention of recurrence. We report the outcome of early aggressive debridement in the acutely infected THA.
Methods
We studied 28 consecutive patients referred with acutely infected THA (18 primaries, 10 revisions) which occurred within 6 weeks of the index operation or of haematogenous spread between 1999 and 2006. Microbiology confirmed bacterial colonisation in all cases with 20 early post-operative infections and 8 cases of acute haematogenous spread. Patients with a cemented THA underwent aggressive open debridement, a thorough synovectomy and exchange of all mobile parts. Uncemented THA were treated as a single stage revision with removal of all implants, aggressive debridement and re-implantation of new prosthesis. Antibiotics were continued in all cases until inflammatory markers and the plasma albumin concentration returned to within normal limits.
Introduction
Total knee replacements (TKR) are among the commonest operations performed in orthopaedic practice. Literature review showed that 10-30% of patients who underwent TKR needed 1-3 units of blood.
Tranexamic acid (TXA) has been popularised as an effective way to reduce blood loss and subsequent blood transfusion.
Our aim was to investigate the value of TXA in reducing blood loss and blood transfusion after TKR and other clinical outcomes such as deep venous thrombosis (DVT), pulmonary embolism (PE), ischaemic heart diseases and mortality.
Patients and Methods
A systematic review and meta-analysis of published randomised and quasi-randomised trials which used TXA to reduce blood loss in knee arthroplasty were conducted.
Background
Total ankle arthrpoplasty (TAA) was performed frequently for ankle deformity caused by rheumatoid arthritis (RA) and osteoarthritis (OA). TAA has some advantages over ankle arthrodesis in range of motion (ROM). However, loosening and sinking of implant have been reported with several prostheses, especially constrained designs. Recently, we have performed mobile bearing TAA and report short term results of this prosthesis followed average 3 years.
Method
20 total ankle prostheses were implanted in patients with RA (n=14) or OA (n=6) in 19 patients (5 male and 14 female, one bilateral), between 2005 and 2009. We used FINE total ankle arthroplasty that is mobile bearing system (Nakashima Medical Co., Ltd, Okayama, Japan). All patients were assessed for American Orthopaedic Foot and Ankle Society (AOFAS) score, ROM in plantar flexion and dorsiflexion at the point of pre-operation and final follow-up. We evaluated radiolucent line, sinking, and alignment of prostheses at final follow-up.
Purpose
The purpose of this study is to evaluate the functional and radiographical results in patients younger than 30 years who underwent cementless third generation ceramic-on-ceramic total hip arthroplasty (THA) for avascular necrosis (AVN) of femoral head.
Materials and Methods
Forty one patients (55 hips) with a minimum 4-year follow-up were included in this study. There were 26 men and 15 women with a mean age of 25.6 years (range, 16 to 29 years). The average duration of follow-up was 5.7 years (range, 4.0 to 6.5 years). All surgeries were done by a single hip surgeon and third generation ceramic-on-ceramic articulation was used. Functional results were measured by Harris hip score (HHS) and WOMAC score. Radiographic evaluation was assessed for loosening and osteolysis according to Gruen's and Delee and Charnley's criteria.
The authors modified the original minimally invasive (MI) two-incision total hip arthroplasty (THA) technique and used large-diameter (32mm, 36mm) ceramic-on-ceramic articulation. One hundred and seventy patients that underwent unilateral MI two-incision THA retrospectively reviewed, and surgical morbidities, functional recoveries, radiological implantation properties, and complications were assessed. The mean follow-up was 30.2 months (range, 24-42 months) and mean patient age was 50.4 years (range, 22-83 years). In the lateral position, an anterolateral approach between the gluteus medius and tensor fascia lata and a posterior approach between the piriformis and gluteus medius was used. Mean operation time was 71.2 minutes (range, 48-91 minutes). Mean Harris hip score improved from 41.8 (range, 10-59) to 96.1 (range, 73-100) at last follow-up, and mean WOMAC score from 66.2 (range, 49-96) to 26.9 (range, 24-39). The mean lateral opening angle of the acetabular component was 38.2° (range, 32.1°-47.7°) and the mean stem position was valgus 1.9° (range, varus 2.3° to valgus 4.8°). One patient suffered an intraoperative femur fracture and another underwent revision surgery due to stem subsidence. No patient experienced dislocation. Our data suggest the this modified technique is safe and reproducible in terms of achieving proper implant positioning and early functional recovery. In particular, the complication rates encountered, especially the dislocation rate, were low.
Purpose
This study was undertaken to assess the result of total hip arthroplasty (THA) performed for fused hips.
Patients and Methods
Twenty nine patients (31 hips), aged 21 to 70 years (average 46 years), underwent THA conversion surgery and were followed for an average of 4.6 years (2.4-12.0 years). There were 23 cases of spontaneous fusion and 8 case of surgical fusion. The causes of joint fusion were tuberculosis in 6 hips, childhood coxitis in 13, ankylosing spondylitis in 6 and childhood trauma in 4. Modified two incision technique was used in 9 hips and in 22 hips, the surgery was performed through a posterolateral approach combined with anterior capsulotomy through gluteus medius and tensor fasica lata interval. In 1 case, greater trochanter osteotomy was done. All acetabular components were inserted at the true acetabulum and the articulations were metal on metal in 7 cases and ceramic on ceramic in 24 cases. Postoperatively, range of motion exercises were encouraged after 2 to 3 weeks of bed rest and subsequent weight bearing crutch ambulation. Then active exercises were strongly encouraged to stretch abductors. We evaluated the clinical and radiological results.
Introduction
Total knee arthroplasty (TKA) is associated with significant blood loss, for which blood transfusion might be necessary. The role of the tourniquet is controversial, though it is widely used by orthopedic surgeons. Its use was believed to be effective in decreasing intraoperative blood loss and creating a bloodless surgical field, which theoretically would facilitate the cementing technique and other surgical procedures. However, reactive blood flow reached its peak within five minutes after the tourniquet had been released. The tourniquet controls intraoperative blood loss, but cannot stop postoperative blood loss. Patients who were managed with a tourniquet during the operation often complained of thigh pain. This was possibly caused by the direct pressure of an inflated tourniquet on the nerves and local soft tissues. Limb swelling and increased soft tissue tension caused by reactive hyperperfusion after tourniquet deflation may also contribute to the wound pain. The aim of our study is to investigate the effect of tourniquet on blood loss and soft tissue damage in TKA.
Materials & Methods
In this prospective, randomized study, 72 patients with primary cemented knee arthroplasty were randomly allocated to two groups (with and without tourniquet). The operation time, blood loss, post-operative hemoglobin, hematocrit, markers of soft tissue damage (myoglobin, Cretine Posphokinase(CK), LDH, GOT, Creatinine), status of rehabilitation, knee pain and thigh pain were monitored until discharge.
The purpose of this study is to prove whether Japanese patients undergoing primary total hip arthroplasty (THA) for the hip dysplasia were able to return to sport after surgery.
A questionnaire survey was completed by 77 patients in 9 males and 68 females between 1 and 3 years after surgery. Mean age at surgery was 66.1 (range, 49 to 87).
In the 3 years before surgery 40 (51.9%) patients were participating in sport. By 1 to 3 years after surgery 43 (55.8%) patients were participating in sport. A total of 33 (82.5%) had returned to their sporting activities by 1 to 3 years after surgery in groups who played sports before surgery and 7 (17.5%) were unable to do with the most common reason being “cannot move as much as I wanted”. On the other hand, a total of 10 (27%) had started playing sports after surgery. The sports activities after surgery were the most common being walking, radio calisthenics, and swimming as low-impact sports. A total of 27 (73%) did not play sports before or after surgery with the most common reason being “fear of damage to the hip joint”.
In conclusion, when Japanese patients who have undergone THA for hip dysplasia choose to participate in sports, orthopedic surgeons should provide information with which to evaluate the risk of sports activity and recommend appropriate sports activity.
562 osteoarthritic knees rated as stage 1 or more according to Kellgren's osteoarthritic knee classification were selected randomly and analyzed radiologically. Eighty cases with the height of 155 cm-160 cm, for which a large number of male and female cases are available (34 male cases, 46 female cases) were extracted for analysis. The values measured were significantly larger in male than in female in any region. In order to clarify differences in morphology between the sexes, the ratio between the values measured of various regions was computed. As a result, the value obtained by dividing the length of medial femoral condyle in anterior-posterior direction and the depth of medial femoral condyle in proximal-distal direction by the width of femur at articular level was 0.87±0.03, 0.56±0.03 in female against 0.81±0.04, 0.52±0.03 in male, respectively. The value obtained by dividing the length of medial tibia condyle in anterior-posterior direction by the width of tibia at articular level was 0.61±0.05 in female against 0.59±0.04 in male. Anteversion of the femur in female was higher than that in male.
When the differences between the sexes were studied, the values measured of various regions were significantly larger in males than in females even in the group of the same height. Morphologically, the knee of males tended to have a larger width than that of females.
Introduction
Total knee arthroplasty (TKA) with a computer-assisted navigation system has been developed to improve the accuracy of the alignment of osteotomies and implantations. One of the most important goals of TKA is to improve the flexion angle. Although accurate soft tissue balancing has been recognized as an essential surgical intervention influencing flexion angle, the direct relationship between post-operative flexion angle and intra-operative soft tissue balance during TKA, has little been clarified. In the present study, therefore, we focused on the relationship between them in cruciate-retaining (CR) TKA with a navigation system.
Materials and methods
The subjects were 30 consecutive patients (2 men, 28 women), who underwent primary CR TKA (B. Braun Aesculap, e-motion) between May 2006 and December 2009. TKAs were performed using a image-free navigation system (OrthoPilot; B. Braun Aesculap, Tuttlingen, Germany). All cases were osteoarthritis with varus deformity. Average patient age at the time of surgery was 74.0 years (range, 62-86 years). After all bony resections and soft tissue releases were completed appropriately using a navigation system with tibia-first gap technique, a tensor was fixed to the proximal tibia and the femoral trial was fitted. Using the tensor that is designed to facilitate soft tissue balance measurements throughout the range of motion with a reduced patello-femoral (PF) joint and femoral component in place, the joint component gap and ligament balance (varus angle) were measured after the PF joint reduced and femoral component in place (Fig.1). Assessments of joint component gap and ligament balance were carried out at 0°, 30°, 60°, 90°, 120° flexion angle, which were monitored by the navigation system. Joint component gap change values during 30°- 0°, 60°- 0°, 90°- 0°, 120°- 0° flexion angle were calculated. The correlation between post operative flexion angles and pre-operative flexion angle, intra-operative joint component gaps, joint component gap change values and ligament balances were assessed using linear regression analysis.
Background
We have often experienced a change of the tone of the hammering sound during the press-fit implantation of cementless acetabular components in total hip arthroplasty (THA). The tone of the impact sound before the press-fit of acetabular components seems to differ from the tone after the press-fit. This change of tone may depend on the accuracy of the fit of the acetabular component, or it may simply be a subjective perception. The aim of this study is to evaluate the impact sounds in the press-fit implantation of cementless acetabular components.
Methods
The hammering sounds in press-fit implantation of acetabular components were studied intraoperatively in 22 patients (28 hips) who underwent primary THA for treatment of advanced osteoarthritis. All operations were performed via the direct anterior approach in a supine position. The hemispherical titanium-alloy acetabular component (TriAD; stryker) was implanted in all patients. A sound level meter (NA-28; RION) was used to record and analyze the sounds. The hammering sounds of the first three hits and last three hits were recorded as the “before press-fit” and “after press-fit” sound samples, respectively. A frequency analysis was then performed at the point of peak sound pressure in each sample.
Background
The bearing surface is one of the important factors that affect the longevity of total hip replacement (THR). The ceramic on ceramic bearing decreases the rate of dislocation event and the amount of wear debris. We encountered cases of incomplete seating of the liner with the TriAD acetabular system.
Patients and Methods
We examined 25 hips in 24 patients who had undergone total hip replacement by using the TriAD shell with a metal-backed alumina liner. We used the Hardinge approach for performing surgery in all patients. Incomplete seating was judged on the basis of plain anteroposterior and/or oblique radiographs obtained immediately and 3 months after the operation.
Introduction
Periprosthetic infection is a serious complication after total hip arthroplasty (THA). Two stage procedure using antibiotic-impregnated cement spacer is one of the treatments for late chronic infection after THA. We investigated the effects of two stage procedure on the infection control and the recurrence of infection after revision THA.
Materials and Methods
We retrospectively reviewed a consecutive series of 10 cases of a periprosthetic infection after hip arthroplasty, including 3 THA and 7 bipolar hemiarthroplasty (BHA). They were treated with two stage procedure using antibiotic-impregnated cement spacer from 2004 to 2009. There were 4 women and 6 men with an average age of 68.4 years. The pathogens were methicilin-resistant Staphylococcus aureus (MRSA) in 3 cases, coagulase-negative Staphylococcus (CNS) in 2 cases, Enterococcus in 2 cases, Streptococcus in 2 cases, and unknown in 1 case.
After removal of the prosthesis, extensive debridement was performed to remove infected tissues and residual cement. After irrigation with iodine solution, antibiotic-impregnated cement spacer was inserted with proximal cement fixation to prevent dislocation and fracture of the cement spacer. The antibiotics that were impregnated in the cement spacer were VCM in 8 cases, MEPM in 1 case, and CAZ in 1 case. Intravenous antibiotics were administrated for 3 weeks after this first stage surgery, and then oral antibiotics were administrated until C-reactive protein (CRP) rates became negative. After confirming the culture of joint fluid contained no pathogens, second stage revision surgery was performed. The average follow-up period after revision THA was 2.3 years.
We investigated the period from first stage surgery to the day when CRP became negative, and to the day of second stage surgery. The incidence of recurrence of infection after revision THA was investigated.
Introduction
Cementless tibial fixation has been used for over 30 years. There are several potential advantages including preservation of bone stock and ease of revision. More importantly, for young active patients there is the potential for increased longevity of fixation. However, the clinical results have been variable, with reports of extensive radiolucent lines, rapid early migration and aseptic loosening. Problems appear to stem from a failure to become sufficiently osseointegrated, which in turn suggests a lack of primary stability. In order to achieve boney ingrowth, interface micromotions should be less than 50 microns, whereas fibrous tissue formation is known to occur if micrmotions are in excess of 150 microns. The degree of micromotion at the bone-implant interface are dependent on the kinematics and kinetics of the replaced joint. Finite element analyses has been used to assess primary stability, however, it is becoming increasing difficult to differentiate performance. The aim of this study was too examine the micromotion for a variety of different activities for three commercially available tibial tray designs.
Methods
A finite element model of the implanted proximal tibia was generated form CT scans of a 72 year old male and material properties were assigned based on the Hounsfield units. Three tray designs were evaluated: LCS, Duofix and Sigma (DePuy Inc, Warsaw USA). The implants were assumed to be debonded, with a coefficient of friction of 0.4 applied to the bone-implant interface except for the porous coated region of the Duofix design, which was assumed to be 0.6. The distal portion the tibia was rigidly constrained. Five activities were simulated based on data from Orthoload.com (patient K1L) including walking, stair ascent, stair descent, sitting down and a deep knee bend. The three force and three moment time histories were discritised to give between 44 and 48 individual load steps. Custom written scripts were used to generate composite peak micromotion plots, which report the peak micromotion that occurs at each point of the contact surface during the gait cycle. The primary stability was then assessed by reporting the maximum micromotion, the average peak micromotion and the percentage of the contact area experiencing micromoitons less than 50 microns.
Introduction
Achieving high flexion after total knee arthroplasty (TKA) is one of the most important clinical results, especially in eastern countries where the high flexion activities, such as kneeling and squatting, are part of the important lifestyle. Numerous studies have examined the kinematics after TKA. However, there are few numbers of studies which examined the kinematics during deep knee flexion activities. Therefore, in the present study, we report analysis of mobile-bearing TKA kinematics from extension to deep flexion kneeling using 2D-3D image matching technique.
Materials and Methods
The subjects were 16 knees of 8 consecutive patients (all women, average age 75.9), who underwent primary mobile-bearing PS TKA (P.F.C. sigma RP-F: Depuy Orthopedics Inc., Warsaw, IN, USA) between February 2007 and May 2008. All cases were osteoarthritis with varus deformity. Postoperative radiographs were taken at the position of extension, half-squatting and deep flexion kneeling 3 month after the surgery, and the degrees of internal rotation of the tibial component was measured by 2D-3D image matching technique. Pre- and post-operative ROM was recorded. Then, we compared the absolute value and relative movement of tibial internal rotation between extension, half-squatting and deep flexion kneeling, and evaluated the correlation of the ROM and the internal rotation.
The options for treatment of the young active patient with isolated symptomatic osteoarthritis of the medial compartment and pre-existing deficiency of the anterior cruciate ligament are limited. The indications for the unicompartimental knee prosthesis are selective. Misalignment femoral-tibia, varo-valgus angle more than 7°, over-weight, and knee instability were considered to be a contraindication.
The potential longevity of the implant and levels of activity of the patient may preclude total knee replacement, and tibial osteotomy and unicompartmental knee arthroplasty are unreliable because of the ligamentous instability.
Therefore, we combined reconstruction of the anterior cruciate ligament first and unicompartmental arthroplasty of the knee.
We included in this study six patients, three males and three female, mean age 53.6 years, that presented only osteoarthritis of medial femoral condyle and ACL deficiency.
In the first group included 2 patients, we performed arthroscopy ACL reconstruction with hamstring and unicompartimental knee prosthesis one-step, and in the second group included 4 patients, we performed the same surgical procedure in two-step.
The clinical and radiological data at a minimum of 1.5 years at follow-up. We evaluated all patients with KOOS score, and IKDC score.
At the last follow-up, no patient had radiological evidence of component loosening, no infection, no knee remainder instability. The subjective and objective outcome assessed with the scale documented satisfactory average results, both in patients of first group and in those of second group.
ACL deficiency induced knee osteoarthritis for incorrect knee biomechanics, and all patients could be submit a total knee replacement.
What method for preventing it? This combined surgical treatment seems to be a viable treatment option for young active patients with symptomatic arthritis of the medial compartment, in whom the anterior cruciate ligament has been ruptured.
Future developments and more data are necessary for standardised surgical approach.
Persistent patellofemoral symptoms can cause patient dissatisfaction after Total Knee Arthroplasty (TKA). The aim of this retrospective study was to evaluate patellar tracking and patient outcomes utilizing two implant designs in TKA.
Medical records and radiographs of two groups of 100 consecutive patients each were reviewed. All patients underwent posterior stabilized TKA by a single surgeon; using the same operative technique but two different implant designs (Group 1: Asymmetric femoral component with deep congruent trochlear groove and Group 2: Asymmetric femoral component with shallow trochlear groove). Data was collected on demographic characteristics, patellar tilt, displacement, prosthesis-bone angle, HSS Patella Score, Knee Society Knee and Function Score. Patellar tilt more than 5° was considered significant. Statistical analysis was done using the SPSS v.16.0.3 software (SPSS, Inc., Chicago, IL).
Patients' age and sex were equivalent in the two groups (p>0.57). Median follow up was 2.2 years. Pre-operative incidence of patellar tilt was similar in both groups (18% vs. 17%). After surgery, these values changed to 30% and 77% respectively. This was statistically significant (p<0.001). The Knee Society Knee and Function Score improved significantly in both groups, however the improvement in the function score was significantly greater in the first group (p=0.001). The improvement in Knee Society Knee Score (50.24 and 48.08; p= 0.18) and post-operative HSS Score (93 vs. 91; p=0.19) were not statistically significant.
Our findings suggest that despite using the same operative technique, patellar tracking was significantly different between the two groups, a finding most likely attributable to the design of the femoral component. Whether the difference in patellar maltracking will affect long-term survival of the patellar component remains to be seen.
Introduction
Studies have documented encouraging results with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss. However, radiographic signs of osseointegration and patterns of reconstitution have not been previously categorized.
Materials and Methods
64 consecutive hips with index femoral revision using a particular stem of this design formed the study cohort. Serial radiographs were retrospectively reviewed by an independent observer. Bone loss was determined by Paprosky's classification. Osseointegration was assessed by a slight modification of the criteria of Engh et al. Femoral restoration was classified according to Kolstad et al. Pain and function was documented using Harris Hip Score (HHS).
Introduction
Although Total Knee Arthroplasty (TKA) has been shown to correct abnormal frontal plane knee biomechanics, little is known about this effect beyond 6 months. The purpose of this study was to compare sequentially the knee adduction moment during level-walking before and after TKA in varus knees. We hypothesized that adduction moment would diminish after TKA proportionate to the tibio-femoral realignment in degrees.
Methods
Fifteen patients (17 TKA's) with varus knees were prospectively enrolled and gait analysis performed prior to, 6 months and 1 year following TKA. Reflective markers were placed on the lower extremity and motion data collected using six infrared cameras (Qtrac, Qualysis). Ground reaction forces were recorded with a multicomponent force plate (Kistler). A repeated-measures ANOVA was used to compare changes in the peak adduction moment and peak dynamic varus angle over time.
Introduction
The importance of frontal and rotational alignment in total knee arthroplasty has been published. Together with conventional instrumentation, computer navigation has been used for many years now. The pro's and con's of navigation are well known since.
Materials & Methods
We present the results of our first 200 total knee arthroplasties with a Patient Specific Instrument System, called Signature (Biomet). With this system an MRI of the hip, knee and ankle is performed. Based on these images, mechanical axis and rotational landmarks are decided. Preoperative planning and templating is done with a computer program. Alignment, rotation, slope, size, positioning and gaps are planned with the software. Based on this templating a femoral guide and a tibial guide are custom made (Materialise) for each patient that will allow only one unique fit and position. Both of these guides are no cutting guides but pinning guides. From that stage on Vanguard Total Knee (Biomet) is implanted with this system applying conventional surgical techniques and rules.
Preoperative alignment was measured on standing full leg X-rays. Rotational alignment was set according to the epicondylar axis. Slope was by default fixed at 3° posterior slope. Femoral flexion was set at 3° by default. Sizing was done with the system. Tourniquet time, blood loss, mean Hb drop and lateral release rate as hospital stay were analyzed. Postoperative full leg X-rays and CT scan were analyzed.
Total Knee Arthroplasty (TKA) has a tendency to change the individual anatomy of the patient within the limits of today used arthroplasty designs. Femoral external rotation will lead to mediolateral overhang by upsizing to avoid lateral notching and downsizing will lead to loss of posterior condylar offset. Posterior slope is usually reduced to avoid problems with posterior stabilized (PS) designs.
We compared 50 bicompartimental arthroplasties (Uni + PFJ) with 50 TKA's. Demographics and BMI are compared. We looked specifically at patient type, preoperative deformity, postoperative function and alignment and results on functional scores.
Bicompartimental arthroplasty is a resurfacing intervention that allows less correction of frontal deformity. Postop alignment was within 3° of varus. Better active flexion was obtained than in TKA. Better function was observed for stair climbing and single leg stability. Rotational position of foot was more natural in bicompartimental as compared to TKA. Functional scores like WOMAC, KOOS and IKDC showed better results for bicompartimental. Illness perception score showed that the resurfacing patient is another patient than the TKA patient. No overhang of components was observed. No change of posterior condylar offset was necessary. Posterior slope on the medial side was minimally reduced.
In conclusion resurfacing by bicompartimental arthroplasty with two individual components (Uni + PFJ) is an excellent solution to gender and ethnic differences. The individual anatomy of the specific patient goes through minimal changes resulting in better functional results.
Total knee arthroplasty has been associated with substantial blood loss in the perioperative period necessitating a substantial risk for blood transfusions. There are various methodologies utilized to decrease postoperative anemia and minimize the need for allogeneic blood transfusions. These include autologous pre-donation, the use of erythropoietin and the use of perioperative cell salvage. Although all of these are successful in decreasing postoperative anemia, there is still a significant risk of allogeneic blood transfusions in the postoperative period. This is a retrospective review of a consecutive series of total knee replacements investigating blood loss and the need for postoperative blood transfusions utilizing MIS surgical techniques and Symphony
PATIENT DEMOGRPAHICS
Between January 1, 2005 to December 31, 2005, 83 total knee arthroplasties were performed in a variety of community hospitals by a single orthopedic surgeon. The mean age was 64 years (SD 11.6, range 28-90) and the mean BMI was 34.1 (SD 7.6, range 21.3 to 53.4). 71% of the patients were females and 29% males.
All patients, regardless of deformity, age or size, had a quad sparing MIS total knee arthroplasty performed utilizing cemented posterior stabilized components and all patellae were resurfaced. No patients pre-donated any blood products or had erythropoietin and no drains were utilized postoperatively. All patients had application of Symphony
RESULTS
The mean preoperative hemoglobin was 14 (SD 1.2, range 10.7 to 16.6). The average postoperative hemoglobin was 10.0 (SD 1.1, range 8.0 to 14.2). The average drop in hemoglobin was 4.0 with a SD of 1.1. A total of two patients were transfused in this series of 83 patients for a total transfusion rate of 2.4%. The average length of stay was 3.4 days with the SD of 3.7. No patients suffered a CVA, myocardial infarction or pulmonary embolus in the two-month postoperative period.
Purpose of the study
to verify, after a period of 5 years, that no particular complication overshadows the benefits of a large diameter metal-on-metal articulation in combination with a conventional femoral stem with regard to stability and functional result.
Patients and methods
Between October 2003 and May 2005, 100 hips in 99 patients were treated with an uncemented Emeraude stem and a Durom Resurfacing Cup made from cobalt-chrome with high carbon content. Mean age at time of surgery was 60 years. 80 of the operated patients were reviewed after a follow-up of 5 years and two months: the results are expressed according to Merle d'Aubigné and Harris, by means of the UCLA and the WOMAC scores. The radiographs were reviewed by independent observers. The patients underwent a chrome and cobalt test in whole blood. Of the 20 patients lost to follow-up, 13 had died, 1 could no longer be located, 1 had been revised because of a peri-prosthetic fracture and the remaining 5 were unable to show up for the follow-up examination. A telephone interview and the WOMAC did not reveal any complication in their cases.
Infected mega-endoprostheses are difficult to treat with systemic antibiotics due to encapsulation of the implant by fibrous tissue, formation of biofilms and antibiotic resistant bacteria. Modifying the implant surface by incorporating a bactericidal agent may reduce infection. Infection rates are typically in the range of 8% to 30%. This study describes a novel process method of “stitching-in” ionic silver into the implant surface,
A novel process has been developed to “stitch in” ionic silver into the upper surface of titanium alloy (Ti6Al4V). The process produces a modification by anodisation of the titanium alloy in dilute phosphoric acid, followed by absorption of silver from an aqueous solution. The engineered surface modification is therefore integral with the substrate and loaded with silver by an ion exchange reaction. Using this technique the maximum inventory of silver for typical a mega-prosthesis is 6mg and this is greater than 300 times lower than the No Observable Adverse Affects Level (NOAEL). Scanning electron microscopy revealed that the silver was concentrated in pits and forming reservoirs of ionic silver exposed to the body tissues.
Laboratory-based studies focusing on the safety and efficacy of silver as a bactericidal agent have included investigation into cytotoxicity using fibroblast and osteoblast cell lines, the impact of silver in reducing corrosion and laboratory testing to establish if the modified surface has an effect on the wear and mechanical characteristics. A range of fatigue, static, tensile pull off tests were performed. The silver elution profiles for both silver loaded and HA coated over a silver loaded surface have been examined. Histological studies were also performed to examine the impact of the silver on osseointegration.
The
To date (May 10) 147 silver treated mega-prostheses have been implanted since March 2006. The majority of implants were distal femoral (29%), proximal tibial (23%) or hemiplevic (10%). The most common indication was revision of a failed limb salvage reconstruction (58%), with the dominant cause of failure being infection. The next most common indication was bone tumour (31%) and the large majority were used in the high risk skeletal locations of the tibia (44%) and the pelvis (27%). Early clinical results are encouraging indicating a significant reduction in the incidence of infection.
Three implants have been retrieved. An analysis of a proximal humeral replacement that had been
This novel process of “stitching-in” silver appears to be a safe and effective surface treatment in helping to control infections of mega-prostheses. This technology has the potential to be transferred to other arthroplasty joints.
Permanent patellar subluxation is treated with surgeries such as proximal realignment and distal realignment, however, it is difficult to cure this condition by using any methods. We performed mobile-bearing total knee arthroplasty (TKA) in a case of severe knee osteoarthritis complicated with permanent patellar subluxation since childhood, and obtained good results without performing any additional procedures.
The patient was an 82-year-old woman with severe pain in the left knee. During the initial examination, the range of motion of the left knee joint was -10°of extension to 140°of flexion, and the Japanese Orthopaedic Association (JOA) score for knee osteoarthritis was 40 points (maximum score: 100). Preoperative radiographs showed a varus deformity in the left lower extremity with a femorotibial angle (FTA) of 188°, the axial view showed luxation of the patella.
We performed TKA using a mobile-bearing implant. Intraoperative findings revealed that the central articular surface of the distal femur had disappeared, and that the patellar articular surface was concave and dome-shaped. The lateral patellofemoral ligament was released; this procedure was identical to that performed in conventional TKA.
Postoperative radiographs showed good alignment, with an FTA of 173°. In the axial view, the patella was located in a reduced position at any angle of knee joint flexion.
The postoperative range of motion of the left knee joint was 0°of extension to 130°of flexion. The patient was able to walk without the support of a T-shaped cane.
There are many surgical treatments for permanent patellar subluxation. The appropriate treatment is selected according to the type and seriousness of the dislocation and the age of the patient.
From the findings of the present case, we believe that in a case of knee osteoarthritis complicated with permanent patellar subluxation, surgery performed using a mobile-bearing implant would eliminate the necessity of performing additional proximal realignment and distal realignment.
More than two thirds of TKA are performed on women. Most TKA systems are based on the male anatomy. Therefore one could ask if a women specific design is needed in Knee Arthroplasty. There are two distinct types of distal femur: the normal one and the narrow one. In the narrow femur the problem of overhang can occur because for a given AP dimension (sizing of the implant) the corresponding ML dimension is too large. Many years ago these findings were already published in different articles. It is only in recent years that interest came from the industry. In our department a study project was initiated in January 2006. This led to the development of the Stature Femoral component for the Advance Medial Pivot knee prosthesis. The first one was implanted in June 2007 and since then it is used in 60% of our female patients and 11% in our male patients. The reason why it is quite often used in male patients is because not only gender influences distal femoral geometry but also morphotype is an important factor. Therefore irrespective of gender, ectomorphs will have smaller ML ratios and thus will have smaller knees and will benefit from a Stature variant. Moreover we have seen that the correct use of the Stature variant can also influence our clinical scores and our percentages of ligament releases with overall better results.
Introduction
Bicompartmental osteoarthritis involving the medial tibiofemoral and the patellofemoral compartments is often treated with total knee replacement. Improved implants and surgical techniques have led to renewed interest in bicompartmental arthroplasty. This study evaluates the radiographic and early clinical results of bicompartmental arthroplasty with separate unlinked components implanted with the assistance of a robotic surgical arm. In addition, we examine the amount of bone resected using unlinked bicompartmental components compared to total knee replacement. Finally, a retrospective review of total knee cases examines the applicability of this early intervention procedure.
Methods
97 patients received simultaneous but geometrically separate medial tibiofemoral and patellofemoral arthroplasties with implants specifically designed to take advantage of a new bone and tissue sparing implantation technique using haptic robotics. These patients came from four surgeons at four different hospitals. The average follow-up was 9 months. Pre- and post-operative radiographs were taken. ROM, KSS and WOMAC scores were recorded. The patients had an average age of 67 yrs (range: 45-95), BMI of 29 ± 4kg/m2. 47% of the patients were male.
We retrospectively reviewed pre and post operative notes from 406 consecutive TKA patients from a single surgeon. Intraoperative data included the integrity of the three compartments and the ACL.
Introduction
High-flexion knee implants have been developed to accommodate a large range of motion (ROM > 120°) after total knee arthroplasty (TKA). In a recent follow-up study, Han et al. [1] reported a disturbingly high incidence of femoral loosening for high-flexion TKA. The femoral component loosened particularly at the implant-cement interface. Highly flexed knee implants may be more sensitive to femoral loosening as the knee load is high during deep knee flexion [2], which may result in increased tensile and/or shear stresses at the femoral implant fixation.
The objective of this study was to analyse the load-transfer mechanism at the femoral implant-cement interface during deep knee flexion (ROM = 155°). For this purpose, a three-dimensional finite element (FE) knee model was developed including high-flexion TKA components. Zero-thickness cohesive elements were used to model the femoral implant-cement interface. The research questions addressed in this study were whether high-flexion leads to an increased tensile and/or shear stress at the femoral implant-cement interface and whether this would lead to an increased risk of femoral loosening.
Materials & methods
The FE knee model utilized in this study has been described previously [3] and consisted of a proximal tibia and fibula, TKA components, a quadriceps and patella tendon and a non-resurfaced patella. For use in this study, the distal femur was integrated in the FE model including cohesive interface elements and a 1 mm bone cement layer. High-flexion TKA components of the posterior-stabilised PFC Sigma RP-F (DePuy, J&J, USA) were incorporated in the FE knee model following the surgical procedure provided by the manufacturer. A full weight-bearing squatting cycle was simulated (ROM = 50°-155°). The interface stresses calculated by the FE knee model were decomposed into tension, compression and shear components. The strength of the femoral implant-cement interface was determined experimentally using interface specimens to predict whether a local interface stress-state calculated by the FE knee model would lead to interface debonding.
The senior author has treated a series of patients with subtrochanteric and diaphyseal femoral stress fractures associated with long-term alendronate or other bisphosphonate usage. Several patients completely fractured their femurs prior to referral. Most patients had consulted other physicians and were referred for presumed neoplasms. All patients had been diagnosed with osteoporosis and had been treated with bisphosphonates. Their plane radiographs revealed abnormalities that are pathognomonic of bisphosphonate-associated stress fractures. However, due to the subtle nature of these new unfamiliar abnormalities, most were unrecognized as such by clinicians (including experienced ISTA member hip surgeons) and radiologists. This series is presented to illustrate this pattern of impending fracture.
The authors have reviewed and will present a series (n=17) of femoral stress fractures in bisphosphonate-treated patients to illustrate the clinical and radiographic pattern of these stress fractures, and review their treatment.
The most common lesion is a subtrochanteric lateral cortical thickening that in actuality is a horizontal plane “dreaded black line” of a stress fracture with surrounding proximal and distal cortical thickening of the endosteal and periosteal bone. The stress fracture line is obscured unless a near-perfect radiographic projection is obtained. The lesion is best seen with CT scans. MRI scans reveal the stress fracture lines with surrounding edema (Fig 1), which may be misinterpreted as a tumor. Without treatment, a low-impact completed fracture will likely occur.
Many bisphosphonate-associated impending subtrochanteric femoral stress fractures are misdiagnosed as trochanteric bursitis, leading to subsequent displaced subtrochanteric fractures [Fig. 2 - Note subtle impending fracture lesion on right, completed fracture on left]. The clinical and subtle radiographic findings must be recognized by orthopaedic surgeons, particularly hip surgeons, to prevent these complete fractures. These fractures are preventable with internal fixation. Long-term administration of bisphosphonates can have adverse effects, and alternatives to long-term continuous dosing must be investigated to determine optimal administration regimens.
Metal Bearings in Hip Arthroplasty – What Have We Learned?
Large metal on metal bearings have come back to hip arthroplasty the past five to ten years with great promise to minimize wear debris, eliminate osteolysis, reduce dislocations and improve range of motion. While some of these claims have proven to be true, new problems have surfaced that threaten the success of these devices. Metalosis, “pseudotumours” and ALVAL (aseptic lymphocytic vasculitis associated lesions) are appearing. These lesions produce pain that is difficult to confirm on routine exam and xray but eventually lead to early revision surgery.
This paper will examine the advantages and complications of this hard bearing surface with a special look at complications, their prevention and management.
Introduction
The purpose of this study is to evaluate the mid-term results of clinical and radiographic results Hi-tech knee a cementless total knee arthroplasty (Nakashima medical Co. Ltd., Okayama, Japan). This TKA system was developed in Chiba University from 1994. The characteristic of this system are flat on flat CR-TKA and cementless fixation. Contact surface are made of titanium alloy and UHMWPE, which is produced by the direct compression mold manufacturing method.
Material and Method
Between May 1998 and May 2005, we performed 53 consecutive primary TKAs for 42 patients. There were 41 women and 1 man with a mean age of 64.4 years (39 to 78 years). The average follow up period was 7 years 8 months (5 years to 12 years). Osteoarthritis knee were 21 knees and rheumatoid arthritis were 32 knees. The mean pre-operative FTA was 181.7 degrees (168 to 203 degrees). The method of the operation went in measured cut technique for all cases. All 53 knees were implanted with a cruciate retaining prosthesis. All comportments, included a patella component, were fixed without cement. Clinical evaluations were performed according to American Knee Society (KS) system, knee score and function score.
Introduction
The MAKO Surgical Rio Robotic Arm utilizes the pre-op CT images to plan positioning of the uni-condylar and patella-femoral components in order to achieve the most desirable kinematics for the knee joint. We hypothesize that the anatomic matching surfaces and the cruciate retaining design of the Restoris knee will best replicate normal knee kinematics. We tested the healthy cadaveric knee versus the MAKO knee and the most common TKR designs in order to evaluate and compare the kinematic properties.
Methods
Six healthy male left knees were dissected to leave only the knee capsule and the quadriceps tendon intact. The femur and the tibia were cut 20cm from the joint line and potted with cement into a metal housing. The knee was attached to a crouching machine capable of moving the knee joint though its normal human kinematics from extension to maximum flexion, validated in previous studies. Forces applied to the quadriceps tendon allowed the knee to flex and extend physiologically, and springs attached to the posterior were substituted as the hamstrings at a rate of half the force exerted by the quadriceps as shown in the literature. Three dimensional visual targets attached to the bones were tracked by computer software capable of recreating the positions of the bones in any given flexion angle. A cruciate retaining and posterior stabilized TKR design were chosen to represent the TKRs most commonly available in the market today. The intact knee, MAKO implanted knee, CR and PS TKR designs were tested in sequence on the same specimens. The computer software analyzed the normal distance between the bone surfaces and plotted the locations of contact which could then be quantitatively compared for each given scenario [Fig. 1].
Aim
Periprosthetic fractures are usually observed in patients aged over 65 years. The incidence of postoperative periprosthetic femur and tibia fractures is rising with increasing number of hip and knee joint replacements and the increasing life expectancy. The aetiology of periprosthetic fractures is multifactorial. Minimal trauma is causal for the fracture in most cases. Other risk factors are: generalized osteoporosis, loosening of the prosthesis and revision arthroplasty. Our aim is restoration of the patient's pre-fracture functional status.
Method
Between 2004 and 2009 in the Asklepios Orthopedic Clinic Hohwald 118 patients (82 women, 36 men) were operated because of periprosthetic fractures. Mean patient age at surgery was 71 years (range 60-87). The right treatment depends on the location of the fracture and the stability of the implant. Very important is also the quality of bone and the patient's general state of health.
