Infection after total knee arthroplasty poses formidable challenges to the surgeon. Once an infection is diagnosed, the identification of the organism and its sensitivity to antibiotics is essential. The host's healing capacity is vital. Optimisation of modifiable comorbidities, supplemental nutrition and cessation of smoking can improve wound healing. Surgical goals include debridement of necrotic tissue and elimination of the dead space. Intravenous antibiotics and a two-stage protocol are the standard of care. At our institution, the first stage is performed with an implant and antibiotic-cement composite. This articulating spacer maintains limb length and tissue compliance. The patient can maintain a functional status between stages. Definitive reconstruction is more readily accomplished with this method in contrast to the static spacer approach. The clinical efficacy of this protocol has been well documented in the literature.
Arthroscopic intervention for early symptoms of arthrosis of the knee was a well-established procedure until Moseley cited his study showing no difference in outcomes when compared to “sham” surgery. Now there is no opportunity for reimbursement with arthroscopic debridement unless mechanical internal derangement can be documented. There are, however, several specific lesions of arthrosis which respond well to arthroscopic intervention and are reimbursed by third party payers. Arthroscopic three compartment microfracture with non-weight bearing and passive motion for eight weeks post- op has significantly relieved symptoms. Second look biopsies have confirmed type II hyaline cartilage and increased joint interval. Proper patient selection is paramount and guidelines will be discussed. Isolated severe patellofemoral arthrosis with patella subluxation responds to arthroscopic patella lateral facetectomy. Jones has reported significant pain relief up to two years with this excellent option for a difficult patient problem. The technique and results will be presented in detail. Loss of terminal extension in the arthritic knee can accelerate deterioration and force earlier decision for TKA. Parson's third tubercle is an osteophyte that forms just anterior to the ACL insertion on the tibia and is the frequent cause of extension loss. Arthroscopic resection of the tubercle results in increased extension and diminishes the stress concentration assuring better longevity for the native knee. The diagnostic characteristics, resection techniques and results of the Dallas series will be presented.
Functional restoration of patella kinematics is an essential component of TKA, whether the patella is replaced or not. This goal is accomplished by a multifactorial approach: establish proper component position and alignment, especially rotation, avoid IR of the femoral and ER of the tibial components, maintain correct joint line position, and achieve symmetrical soft tissue balance Most modern TKA designs have an anatomic trochlear groove shape to enable midline tracking. Patella implants are better designed as well with three equilateral lugs for fixation and either dome or anatomic shape. The apex of the patella component should be aligned with the apex of the patella raphe which is more medial than lateral. This method leaves an island of exposed lateral patella facet which is managed with the “lateral slat technique” to be described. It is essentially an intraosseous lateral release. The early mobilisation of modern TKA patients demands watertight closure to prevent soft tissue attenuation and late tracking issues. When confronted with a patient with a laterally dislocated patella, implementation of the “lateral slat technique” should be done at the approach to obtain midline tracking. Such patients require a median parapatellar (MPP) approach and may need distal-lateral vastus medialis advancement (Insall Procedure). Adherence to the principles iterated herein will produce a happy patient with good patello-femoral kinematics and function.
There is strong current interest to provide reliable treatments for one- and two-compartment arthritis in the cruciate-ligament intact knee. An alternative to total knee arthroplasty is to resurface only the diseased compartments with discrete compartmental components. Placing multiple small implants into the knee presents a greater surgical challenge than total knee arthroplasty, and it is not certain natural knee mechanics can be maintained. The goal of this study was to compare functional kinematics in cruciate-intact knees with either medial unicondylar (mUKA), mUKA plus patellofemoral (mUKA+PF), or bi-unicondylar (biUNI) arthroplasty using discrete compartmental implants with preparation and placement assisted by haptic robotic technology. Nineteen patients with 21 knee arthroplasties consented to participate in an I.R.B. approved study of knee kinematics with a cruciate-retaining multicompartmental knee arthroplasty system. All subjects presented with knee OA, intact cruciate ligaments, and coronal deformity ranging from 7° varus to 4° valgus. All subjects received multicompartmental knee arthroplasty using haptic robotic-assisted bone preparation an average of 13 months (6–29 months) before the study. Eleven subjects received mUKA, five subjects received mUKA+PF, and five subjects received biUKA. Subjects averaged 62 years of age and had an average body mass index of 31. Combined Knee Society Pain/Function scores averaged 102 ± 28 preoperatively and 169 ± 26 at the time of study. Knee range of motion averaged −3° to 120° preoperatively and −1° to 129° at the time of the study. Knee motions were recorded using video-fluoroscopy while subjects performed step-up/down, kneeling and lunging activities. The three-dimensional position and orientation of the implant components were determined using model-image registration techniques (Fig. 1). The AP locations of the medial and lateral condyles were determined by computing a distance map between the femoral condyles and the tibial articular surfaces.INTRODUCTION
METHODS
Angular mismatch of the modular junction between the head and the trunion has been recognized as a contributing factor to fretting and corrosion of hip prostheses. Excessive angular-mismatch can lead to relative motion at the taper interface, and tribo-corrosion of the head-neck junction secondary to disruption of the passive oxide layer. Although manufacturing standards have been adopted to define acceptable tolerances for taper angles of mating components, recent investigations of failed components have suggested that stricter tolerances or changes in taper design may be necessary to avoid clinical failures secondary to excessive taper wear and corrosion. In this study we examine the effect of angular-mismatch on relative motion between the taper and bore subjected to normal gait load using finite element methods. Computer simulations were executed using a verified finite element model (FEM), the results from which were determined to be consistent with literature. A stable, converging hexahedral mesh was defined for the trunnion (33648 elements) and a tetrahedral mesh for the femoral head (51182 elements). A friction-based sliding contact was defined at the taper-bore interface. A gait load of 1638N (2.34 × BW, BW = 700N) was applied at an angle of 30° to the trunnion axis (Figure 1) on an assembled FEM. A linear static solution was set up using Siemens NX-Nastran solver. Angular-mismatch was simulated by incrementing the conical half-angle of the bore to examine these cases: 0°, 0.005°, 0.010°, 0.015°, 0.030°, 0.050°, 0.075°, 0.100°, 0.200°and 0.300°.Introduction:
Methods:
The sealing function of the acetabular labrum is central to the stability of the hip and the health of the joint. Disruption of the labrum has been shown to reduce intra-articular pressure and increase the rate of cartilage consolidation during static loading. Functional activities require movement of the hip through wide ranges of joint motion which disrupt joint congruency, and thus may alter the seal. This study was performed to test the hypothesis that the sealing function of the labrum varies with the position of the hip during functional activities. Six fresh cadaveric hip joint specimens were obtained from donors of average age 45.5 ± 16.1 years (range 25–63 years). Each specimen was dissected free of soft tissue, leaving the capsule and labrum intact, potted in mounting fixtures, and placed in a loading apparatus. Catheters were inserted into the central and peripheral compartments of each hip to allow infusion of fluid and monitoring of compartment pressures via miniature transducers (OMEGA Engineering, Inc). After application of a joint load of 0.50 BW, fluid was introduced into the central compartment at a constant rate until transport was indicated by a rise in pressure within the peripheral compartment. These measurements were performed with each hip placed in 10 functional positions ranging from −5 to 105 degrees of flexion, −5 to 13 degrees of abduction, and −25 to 35 degrees of external rotation simulating the sequential stages of gait, stooping, and pivoting. Motion analysis was performed via reflective marker arrays attached to the femur and pelvis to allow computer visualization of the position of the pelvis and femur using CT reconstructions. In each hip position, we measured the peak pressure (kPA) developed within the central compartment prior to fluid transfer to the peripheral compartment.Introduction:
Methods:
Experimental disruption of the labrum has been shown to compromise its sealing function and alter cartilage lubrication. However, it is not known whether pathological changes to the labrum secondary to femoro-acetabular impingement (FAI) have a similar impact on labral function. This study was performed to determine the effect of natural labral damage secondary to abnormal femoral morphology on the labral seal. Ten intact hip specimens were obtained from male donors (47.8 ± 1.5 yrs) for use in this study. CT reconstructions demonstrated that 6 specimens were of normal morphology, while 4 displayed morphology typical of cam-FAI. Specimens were dissected free of the overlying soft tissue, leaving the capsule and labrum intact. Each specimen was potted and placed in a loading apparatus (0.5 BW). Pressures developed within the central and peripheral compartments were monitored with miniature pressure transducers. The sealing capacity of the labrum was measured by introducing fluid into the central compartment at a constant rate until transport was detected from the central to the peripheral compartment. These measurements were performed in 10 functional positions simulating sequential stages of gait, stooping, and pivoting. During testing, the 3D motion of the femoral head in the acetabulum was measured with motion analysis combined with computer visualization. Peak pressures were compared between specimens with and without labral damage for each of the three activities (p < 0.05).Objectives:
Methods:
Total knee arthroplasty (TKA) has been established as a successful procedure for relieving pain and improving function in patients suffering from severe knee osteoarthritis for several decades now. It involves removing bone from both the medial and lateral compartments of the knee and sacrificing one or both of the cruciate ligaments. This in turn is likely to have an impact on the patients' functional outcome. In subjects where only one compartment of the knee joint is affected with osteoarthritis then unicondylar knee arthroplasty (UKA) has been proposed as an alternative procedure to TKA. This operation preserves the cruciate ligaments and removes bone only from the affected side of the joint. As a result there is the possibility of an improved functional outcome post surgery. UKA has been associated with faster recovery, good functional outcome in terms of range of motion and it is bone sparing compared to TKA. However, the biggest obstacle to UKA success is the high failure rates. The aim of this study was to compare the functional outcome of computer navigated TKA (n=60) and UKA (n=42) patients 12 month post operation using flexible electrogoniometry. Flexible electrogoniometry was used to investigate knee joint kinematics during gait, slopes walking, stair negotiation, and when using standard and low chairs. Maximum, minimum and excursion knee joint angles were calculated for each task. The biomechanical assessment showed statistically significant improvements in the knee kinematics in terms of maximum ( Therefore, UKA patients were showed to have a significantly better functional outcome in terms of the maximum knee joint angle during daily tasks. A limitation of this study is that it compares two cohorts rather than two randomised groups. It is expected that UKA patients will have a better functional outcome. Our results suggest that for patients with less severe knee osteoarthritis, UKA may offer a better functional outcome than the more common surgical option of TKA. The recent advancements in computer assisted and robotic assisted knee arthroplasty has the possibility to improve the accuracy of UKA and therefore led to the increase in confidence and in usage in a procedure which has the potential to give patients a superior functional outcome.
Unicompartmental knee arthroplasty (UKA) has been gaining popularity in recent years due to its perceived benefits over total knee replacements, such as greater bone preservation, reduced operating-room time, better postoperative range of motion and improved gait. However there have been failures associated with UKA caused by misalignment of the implants. To improve the implant alignment a robotic guidance system called the RIO Robotic Arm has been developed by MAKO Surgical Corp (Ft. Lauderdale, FL). This robotic system provides real-time tactile feedback to the surgeon during bone cutting, designed to give improved accuracy compared to traditional UKA using cutting jigs and other manual instrumentation. The University of Strathclyde in association with Glasgow Royal Infirmary has undertaken the first independent Randomised Control Trial (RCT) of the MAKO system against the Oxford UKA – a conventional UKA used in the UK. The trial involves 139 patients across the two groups. At present the outcomes have been evaluated for 30 patients. 14 have received the MAKO unicompartmental knee arthroplasty and 16 the Oxford UKA. Both groups were seen 1 year post-operatively. Kinematic data was collected while subjects completed level walking using a Vicon Nexus motion analysis system. Three-dimensional hip, knee and ankle angles were compared between the two arthroplasty groups. Our initial findings indicate that hip and ankle angles show no significant statistical difference, however there is a significant difference (p < 0.05) in the knee angles during the stance phase of gait. Data shows higher angles achieved by the MAKO group over the Oxford. It would appear from our early findings that the MAKO RIO procedure with Restoris implants gives at least comparable functional outcome with the conventional Oxford system and may prove once our full sample is available for analysis to produce better stance phase kinematics with a more active gait pattern than the conventional Oxford procedure. Further work includes analysing the data obtained from the patients in a number of other activities. These include a full biomechanical analysis of ascending and descending a flight of stairs, sit to stand and a deep knee lunge. The high demand/high flexion tasks in particular may reveal if there's an advantage to using the MAKO procedure over the Oxford. If there is a direct correlation between alignment and patient function then this effect could be more significant in the more demanding patient tasks.
Obtaining primary wound healing in Total Joint Arthroplasty (TJA) is essential to a good result. Wound healing problems can occur and the consequences can be devastating to the patient and to the surgeon. Determination of the host healing capacity can be useful in predicting complications. Cierney and Mader classified patients as Type A: no healing compromises and Type B: systemic or local healing compromises factors present. Local factors include traumatic arthritis with multiple previous incisions, extensive scarring, lymphedema, poor vascular perfusion, and excessive local adipose deposition. Systemic compromising factors include diabetes, rheumatic diseases, renal or liver disease, immune compromise, steroids, smoking, and poor nutrition. In high risk situations the surgeon should encourage positive patient choices such as smoking cessation and nutritional supplementation to elevate the total lymphocyte count and total albumin. Careful planning of incisions, particularly in patients with scarring or multiple previous operations, is productive. Around the knee the vascular viability is better in the medial flap. Thus, use the most lateral previous incision, do minimal undermining, and handle tissue meticulously. We do all potentially complicated TKAs without tourniquet to enhance blood flow and tissue viability. The use of perioperative anticoagulation will increase wound problems. If wound drainage or healing problems do occur immediate action is required. Deep sepsis can be ruled out with a joint aspiration and cell count, and negative culture and sensitivity. All hematomas should be evacuated and necrosis or dehiscence should be managed by debridement to obtain a live wound. Options available for coverage of complex wound problems include myocutaneous flaps, pedicled skin flaps, and skin grafts. Wet, occlusive dressings and wound VACs encourage epithelisation of chronic wounds.
To study the incidence of delayed consolidation of regenerate in children undergoing correction or lengthening of lower limb deformities using an external fixator. Between 2006 and 2011, 150 patients with lower limb deformities (excluding feet) were treated in our unit using external fixators. A retrospective review of our prospective database was carried out to identify patients with poor regenerate formation requiring bone grafting. Patients with acute fractures, pseudarthrosis of the tibia due to neurofibromatosis and those above the age of eighteen were excluded. An independent observer reviewed the medical records and radiographs. Eleven patients with ages ranging from 2 years 5 months to 17 years 5 months (mean average 9 years 9 months) formed the basis of our study – 3 males and 8 females. Factors that were associated with this complication include age greater than twelve years (10 patients), lack of weight bearing (6 patients), previous fixator (5 patients) and smoking (5 patients). The regenerate was deficient in nine tibial segments and two femoral segments. Six of the deficient tibial regenerates were at a proximal site whilst three were distal. There was no significant difference in length gained between these sites (p < 0.5). The mean time to regenerate bone grafting was 7 months. Time to healing following bone grafting was 2.5 months.Purposes of the Study
Methods and Results
There are special circumstances in which revision total knee arthroplasty is not an option. The relative indications for the alternatives to revision TKA are: - Recurrent deep infection - Immunocompromised patient - Extensor mechanism loss - Extensive, non-reconstructable soft tissue loss - High functional demand, young age Remember the three A's as alternatives to revision TKA: arthrodesis, arthroplasty (resection), and amputation. Successful arthrodesis requires elimination of infection, coaptation of bone surfaces and rigid immobilisation. The proper position for arthrodesis is 15 degrees of knee flexion to allow foot clearance. If bone loss is greater than 3 cm fuse the knee in full extension. Avoid hyperextension. Achieve 5 degrees of valgus in correct rotation and use intramedullary instruments from TKA sets for best cuts. External fixation techniques as well as intramedullary internal fixation techniques will be described. Resection arthroplasty is indicated for salvage of an infected total knee when the patient is not a candidate for reimplantation. These patients usually have extensive soft and hard tissue loss. Procedure may be well tolerated and functional. Ancillary support with a long leg drop- lock KAFO increases stability and provides motion. Patients finding resection unacceptable are more likely to accept fusion or amputation; therefore resection may be a staging procedure. Amputation is indicated for failed multiple revisions, intractable or life threatening infection. Also should be indicated when there is a low chance of a successful arthrodesis. Ablate at the lowest level for infection eradication but good maintenance of function. Pedicle muscle flaps can be useful to fill dead spaces. Remember, elderly patients have limited ambulation potential because of high energy requirements of above knee amputation.
The Pelvic Support Osteotomy (PSO) or Ilizarov Hip Reconstruction(IHR) is well described for the treatment of septic sequelae of infancy. The purpose of this study was to clinically, functionally and radiographically assess our short-term results of this procedure. 25 patients (16 boys, 9 girls) who had undergone a IHR using the Ilizarov/TSF construct over a period of 10 years for a variety of pathologies were reviewed. The mean age at surgery was 15 years 4 months. The pre-operative diagnoses were SCFE(10), hip sepsis (6), DDH (6) and Perthes (3). All had significant leg length discrepancies, 16 had a painful stiff hip, 6 had a painful mobile hip and 3 had a painless unstable hip. At surgery, a mean measured proximal valgus angle of 51° and a mean extension angle of 15° was achieved. Distal femoral lengthening averaged 4.2 cm and distal varus correction was a mean of 8°. The mean fixator time was 173 days. At a mean of 2 years and 7 months follow-up the lower-extremity length discrepancy had improved from a mean of 5.6 cm apparent shortening to 2.3 cm. Trendelenberg sign was eliminated in 18/25 cases. Improvements in range of hip movements and gait parameters were observed. Stance time asymmetry, step length asymmetry, pelvic dip and trunk lurch improved significantly. One patient had conversion to a total hip replacement after 7 years, 4 patients required re-do PSO due to remodelling of the proximal osteotomies, two had heterotopic ossification and two had significant knee stiffness due to lack of compliance. The early results of IHR are encouraging to equalise limb lengths, negate trendelenburg gait, provide a mobile hip with a reasonable axis and the possibility of conversion to THR in the future if needed. Complications need to be anticipated and the effects of remodelling and maintaining adequate knee range of motion must be emphasised.
To demonstrate how contemplating reconstructive options among members of Orthoplastic team can prevent accidental damage during initial wound debridement in foot and ankle injuries Complex defects of the foot and ankle often require input from plastic and orthopaedic surgeons. There are different reconstructive options but one excellent regional option for small defects is the Extensor Digitorum Brevis muscle (EDB) flap. The anatomy of the flap and surgical technique and utility are described and demonstrated through a case series. We present a series of 4 consecutive cases of the use of the pedicled EDB flap for soft tissue coverage of difficult defects around the foot and ankle. This regional pedicled flap can be proximally based to cover defects around the ankle or distally based for distal foot coverage. When possible, it facilitates a reconstruction with minimal donor site morbidity, shorter operating times, and fewer complications than alternative options The flap would usually be performed by the plastic surgical member of the orthoplastic team, but an understanding of it by foot and ankle and reconstructive orthopaedic surgeons is relevant as it's vascular supply via the lateral tarsal artery can be easily damaged, preventing its use in the management of wound complications or trauma.Statement of purpose
The reverse obliquity fractures of the proximal femur are anatomically and mechanically different from most intertrochanteric fractures. These fractures are complex and very difficult to treat. To evaluate the results of the treatment of reverse obliquity intertrochanteric fractures with cephalomedullary nails. Between 2005 and 2009, 1179 extracapsular fractures of the proximal femur were treated at our institution. Retrospective review of these x-rays identified 59 patients with reverse obliquity fracture pattern. We analysed our results of cephalomedullary nailing of these complex fractures and evaluated factors responsible for failure of fixation.Introduction
Materials and Methods
Traditional Total Knee Arthpolasty (TKA) replaces all 3 compartments of the knee for patients diagnosed with OA. There might be functional benefit to replacing only damaged compartments, and retaining the normal ligamentous structures. There is a long history of performing multi-compartment arthroplasty with discrete components. Laskin reported in 1976 that good pain relief and acceptable clinical results were achieved at two years in patients with bi-unicondylar knee replacement [Laskin 1976]. Other authors also have reported on bi-unicompartmental knee arthroplasty achieving successful clinical outcomes [Stockley 1990; Confalonieri 2005]. Banks et al. reported that kinematics of bi-unicompartmental arthroplasties during gait demonstrated some of the basic features of normal knee kinematics [Banks 2005]. These reports suggest that a modular approach to resurfacing the knee can be successful and achieve satisfactory clinical and functional results. The primary objective of this study is to compare the functional outcomes of three patient groups treated for osteoarthritis.Introduction
Objective
The knee is the commonest joint to be affected by osteoarthritis, with the medial compartment commonly affected. Knee osteoarthritis is commonly bilateral, yet symptoms may initially present unilaterally. Higher knee adduction moment has been associated with the development and progression of medial compartment knee osteoarthritis. To assess the effect of lateral wedge insoles on the asymptomatic knee of patients with unilateral symptoms of medial compartment knee osteoarthritis.Background
Objectives
We reports the accuracy of direct Magnetic Resonance Arthrography (MRA) in detecting Triangular Fibrocartilage Complex (TFCC), Scapho-Lunate Ligament (SLL) and Luno-Triquetral Ligament (LTL) tears using wrist arthroscopy as the gold standard. We reviewed the records of all patients who underwent direct wrist MRA and subsequent arthroscopy over a 4-year period between June 2007 and March 2011. Demographic details, MRA findings, arthroscopy findings and the time interval between MRA and arthroscopy were recorded. The scans were performed using a 1.5T scanner and a high resolution wrist coil. All scans were reported by a musculoskeletal radiologist. Sensitivity, specificity, positive and negative predictive values (PPV & NPV) were calculated.Introduction
Methods
Acute renal dysfunction (ARD) following orthopaedic surgery is known to increase morbidity, mortality, and length of hospital stay. The aim of this study was to compare the incidence of new acute post-operative renal dysfunction between two cohorts of elective orthopaedic surgical patients receiving either cefuroxime or a combination of gentamicin and flucloxacillin as prophylactic antibiotic regimes. The study was initiated following a change in antibiotic prophylaxis within our unit from cefuroxime to gentamicin and flucloxacillin. Using a standardised data collection tool we retrospectively reviewed medical records of 238 patients who had received 1.5g of cefuroxime (TKR: n = 128; THR: n=110). This data was compared to prospectively collected data from 254 patients (TKR=117 THR=137) who had received Flucloxacillin 2g and Gentamicin (with the dose based on height). Primary outcome measure for the study was the RIFLE criteria which grades renal impairment: 0-Nil, 1-Risk, 2-Injury, 3-Renal failure.Introduction
Method
Hip arthroscopy is a relatively new procedure and evidence to support its use remains limited. Well-designed prospective clinical trials with long-term outcomes are required, but study design requires an understanding of current practice. Our aim was to determine temporal trends in the uptake of non-arthroplasty hip surgery in England between 2001 and 2011. Using procedure and diagnosis codes, we interrogated the Hospital Episode Statistics (HES) Database for all hip procedures performed between 2001 and 2011, excluding those relating to arthroplasty, tumour or infection. Osteotomy procedures were also excluded.Introduction
Methods
The aim of this study was to investigate PDGF release in the peripheral circulation following trauma and to correlate it with the numbers of MSCs in iliac crest bone marrow (BM) aspirate. Trauma patients with lower extremity fractures (n=18, age 21–64 years) were recruited prospectively. Peripheral blood was obtained on admission, and at 1, 3, 5 and 7 days following admission. The serum was collected and PDGF was measured using ELISA. Iliac crest (BM) aspirate (20ml) was obtained on days 0–9 following admission. MSCs were enumerated using standard colony-forming unit fibroblasts (CFU-F) assay.Objective
Methods
Subtle deformities of the acetabulum and proximal femur are recognised as biomechanical risk factors for the development of hip osteoarthritis (OA) as well as a cause of hip and groin pain. We undertook this study to examine relationships between a number of morphological measurements of the acetabulum and proximal femur and the hip pain in a 20-year longitudinal study. In 1989 women of 45–64 years of age were recruited. Each had an AP-Pelvis radiograph at Year-2. These radiographs were analysed using a validated programme for measuring morphology. All morphological measurements were read blinded to outcome. At year 3 all participants were asked whether they experienced hip pain (side specific). This was repeated at visits up to and including 20-years. Logistic regression analysis (with robust standard errors and clustering by subject identifier) was performed using hip pain as a binary outcome. The model adjusted for baseline age, BMI and joint space and included only participants who were pain free on initial questioning.Introduction
Methods
Segmental tibia fractures are high-energy injuries that are difficult to treat. We report on the use of the Ilizarov Method to treat 40 consecutive AO42C (35) and AO42B3 (5) fractures by a single surgeon. Fractures with bone loss requiring transport were excluded, as were fractures initially treated with nail or plate. 28 adult males, 12 adult females, average age 43. The most common mechanism of injury was RTA (50%). 12 (30%) had associated injuries. 19 (48%) fractures were open (6 3A, 13 3B) and 21 closed. 24 (60%) had temporary monolateral external fixation before definitive treatment. The mean time from injury to definitive Ilizarov frame was 8 days.Introduction
Patients
To review the outcome of deep prosthetic infection in patients following hip hemiarthroplasty surgery. A retrospective case-note analysis was performed of deep infection coded hip hemiarthroplasty patients between 2004–2009. Patients were selected when there was proven microbiology from deep wound swabs or tissue specimens.Aim
Method
Total hip arthroplasty (THA) in teenagers is uncommon and previously associated with poor survival rates. However it is sometimes the only option remaining to relieve pain and improve function in patients with advanced hip disease. We report on the clinical and radiological outcomes of THA in teenage patients. Medical records and radiographs of all consecutive teenage patients undergoing THA at a tertiary referral centre between 2006–2011 were reviewed. Mean follow-up was 3.4 years (range 0.6–6.8) with 9 patients having at least 5 years follow-up. Post-operative Harris hip, Oxford hip (OHS) and University of California Los Angeles (UCLA) activity scores were recorded. 51 THAs were performed in 43 patients (21 male, 22 female) with a mean age of 17 years (range 12–19). The 5 most common indications were slipped upper femoral epiphysis osteonecrosis 15 (29.4%), developmental hip dysplasia osteonecrosis 5 (9.8%), multiple/spondylo-epiphyseal dysplasia 5 (9.8%), chemotherapy-induced osteonecrosis 4 (7.8%) and idiopathic osteonecrosis 4 (8.2%). 46 (90%) were uncemented THAs and 5 (10%) were reverse hybrid THAs with 7 computer assisted design/manufacture (CADCAM) femoral implants. Articular bearings were ceramic/ceramic in 40 (78.4%), metal/metal 6 (11.8%), metal/polyethylene 3 (5.9%) and ceramic/polyethylene 2 (3.9%). The survival rate was 96% with 2 acute head revisions for 1 sciatic nerve palsy and 1 instability. Other complications (8.2%) included 1 dislocation, 1 sciatic nerve palsy that resolved, 1 surgical site infection and 1 unexplained pain. At latest follow-up, the mean Harris hip score was 90 (68–99), OHS was 42 (32–48) and UCLA activity score was 6 (4–9). Radiological analysis showed 2 patients with lucent lines around the acetabular component, but no signs of osteolysis or wear. As one of the largest studies on teenagers undergoing THA, we report good clinical and radiological outcomes at short to intermediate term follow-up.
To investigate the effectiveness of a decision-based protocol designed to minimise the use of medial incisions when performing crossed-wire fixation of supracondylar fractures of the distal humerus whilst minimising ulnar nerve injury. We have employed a protocol for placing the medial wire during crossed k-wire fixation of supracondylar fractures dependent upon the medial epicondyle. When this is palpable, the wire is introduced percutaneously; when it is not, a mini-incision is made. All cases of closed reduction and crossed K-wiring of supracondylar fracture over a three year period (2008–2011) were identified from our department database. Cases with a neurological injury identified pre-operatively, and those in which the protocol had not been followed were excluded. Casenotes were reviewed to determine the incidence and outcomes of post-operative ulnar nerve deficit.Aim
Method
This RCT compared electromagnetic (EM) navigated and conventional total knee arthroplasty (TKA) in terms of clinical and functional outcomes. 200 patients (navigated=102, conventional=98) were recruited. Oxford Knee Scores (OKS) and the American Knee Society Score (AKSS) were recorded pre operation, 3 and 12 months after surgery. Post operative (coronal, sagittal and rotational) alignment was analysed from 3D CT scans taken 3 months after surgery. An objective functional assessment was completed using electrogoniometry on a sub group (navigated=60, conventional=57) at 12 months post surgery. The EM group showed statistically significantly improved OKS (p=0.04) and AKSS (p=0.03) scores at 3 months post operation. However at 12 months post surgery there was no difference between the two groups. At the 1 year follow up it was reported that 9% of the navigated compared to 14% of the conventional group were dissatisfied with their surgical outcome. The mechanical axis alignment of 90% of the navigated group was within 3 degrees of neutral compared to 84% of the conventional group. Although all alignment parameters except for tibial rotation was improved in the navigated group they did not reach significance apart from femoral slope alignment (p=0.01). There was no statistically difference between the surgical groups in terms of the maximum, minimum and excursion knee joint angles during 12 functional activities. Only the knee kinematic function cycles for level walking resulted in statistically significant higher knee joint angles during 55–70% of the gait cycle in the navigated group. Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical and functional improvements at early follow-up; however this difference was not sustained at 12 months. The EM group reported minimal gait improvements. Proving cost-effectiveness for navigation systems in TKA remains a challenge.
Solid or cystic pseudotumour is a potentially destructive complication of metal on metal (MoM) couples, usually needing revision surgery. However, complete clearance of the pseudotumour is unlikely at times. This prospective case-controlled study reports cases which had recurrence after revision surgery for pseudotumour related to metal on metal hip couples. A total of 37 hips (33 MoM hip resurfacing and four big head MoM total hip arthroplasty (THA)) were revised for pseudotumour during the last 10 years. The patient demographics, time to revision, cup orientation, operative and histological findings were recorded for this cohort. Patients were divided into two groups - group R (needing re-revision for disease progression) and group C (control - no evidence of disease progression). Oxford hip scores (OHS, 0–48, 48 best outcome) were used to assess clinical outcome. The diagnosis of disease progression was based on recurrence of clinical symptoms, cross-sectional imaging, operative and histological findings.Introduction
Methods
Low back pain is a common complaint, affecting up to one third of the adult population costing over £1 billion to the NHS each year and £3.5 billion to the UK economy in lost production. The demand for spinal injections is increasing allowing for advanced spinal physiotherapists to perform the procedure. The objective of this study was to investigate outcome following spinal injections performed by consultant spinal surgeon (n=40) and advanced spinal physiotherapists (ASP) (n=40) at our centre. Data on 80 patients who had received caudal epidural (n=36), nerve root block (n=28) and facet joint injections (n=16) form August 2010 to October 2011 consented to be in the study. 40 patients in each group completed Oswestry Disability Index (ODI), Visual Analogue Scores (VAS) before and 6 weeks after the procedure and patient satisfaction questionnaire investigating their experience and any complications related to the spinal injection retrospectively. The study included 32 males and 48 females. Mean age 57 years, range 21–88. [Consultant group M:17, F:23 mean age: 55, range 21–81. ASP group M:15, F:25 mean age 59, range 22–88]. Measures of patient satisfaction and outcome were obtained; using 2 tailed independent samples Introduction and aims
Method and Materials
Pyogenic spinal infection (PSI) is an increasingly common presentation to spinal units in the UK. Its investigation and diagnosis is often delayed. The purpose of this study was to determine the prognostic significance of the inflammatory marker levels on admission on achieving a positive microbiological diagnosis in patients with PSI. Retrospective case series review of all patients presenting with PSI to our unit.Objective
Study design
A retrospective analysis was carried out to determine the influence of pre-existing spinal pathology on the outcome of Total Knee Replacement surgery. Data was collected from 345 patients who had undergone Total Knee Replacement, at four centres in the UK, between 2000 and 2007. Oxford Knee Scores (OKS), American Knee Society Scores (AKSS) and SF-12 questionnaires were recorded prospectively. Data was collected pre-operatively and then post-operatively at 3 months, 1 year and 2 years. Patients were divided into those with (n=40) and without a history of low back pain (n=305). In addition to determining the influence of low back pain on outcome after Total Knee Replacement we also examined the influence of concomitant hip and ankle pathology in the same cohort of patients. OKS scores were significantly worse for patients with symptomatic low back pain at 3 (p=0.05), 12 (p=0.009) and 24 months (p=0.039) following surgery. SF-12 physical scores followed a comparable pattern with significance demonstrated at 3 (p=0.038), 12 (p=0.0002) and 24 months (p=0.016). AKSS followed a similar pattern, but significance was only reached at 1 year (p=0.013). The mental component of the SF-12 measure demonstrated a significant improvement in patients' mental health post-operatively for patients with no history of low back pain. In contrast patients with low back pain showed no improvement in mental health scores post-operatively. In contrast to low back pain, hip and ankle pathology had no statistically significant detrimental effect on the outcome of Total Knee Replacement surgery. This study demonstrates that low back pain significantly affects the functional outcome after Total Knee Replacement surgery and that patients with low back pain show no improvement in mental health post-operatively.
It has been speculated that impact deformation of thin 1-piece cups used for modern metal-on-metal hip replacement may contribute to early failure. The purpose of this study was to reproduce typical impact deformation and quantify the effect of this on the frictional torque generated at the hip. We tested nine hip couples of three designs (the ASR, BHR and Durom) and three sizes (42mm, 46mm and 50mm). A custom compression device was designed to replicate the in vivo forces and impact deformation of 1-piece metal cups reported in the literature. Each cup was mounted in the device, which itself was mounted on a mechanical testing machine. The cups were compressed with incremental loads up to a maximum of 2000N. At each increment we measured cup deformation, and then the head component was seated into the cup. The hip was lubricated and the head component rotated 60 degrees axially within the cup and the axial torque was measured.Introduction
Methods
Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown. The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL. Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded. Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05). Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05). Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee.
The aim of this study was to determine the influence of electromagnetic (EM) navigation in total knee arthroplasty (TKA) on post operative function. In this double blinded randomised control trial, patients with osteoarthritis either received TKA using conventional techniques (n = 49) or EM navigation (iNav Portable Navigation System, Zimmer Orthopaedics) (n = 52). All of the patients were reviewed in the Outcomes Clinic at 3 and 12 months. At 12 months post operation the patients completed an objective biomechanical functional assessment using flexible electrogoniometers, which recorded dynamic knee kinematics during daily activities. Knee joint flexion and extension moments were recorded at the 12 month post operation assessment. The functional assessment included validated questionnaires (Oxford Knee Score, American Knee Society Score, WOMAC Score and Short Form SF-36 Score). All patients underwent CT scanning of the implanted prosthesis to assess component alignment. Improved alignment was recorded in the navigated group. However there was no significantly significant difference between the two surgical groups in terms of the subjective questionnaire scores. The biomechanical assessment showed no statistically significant differences in the maximum, minimum or excursion knee joint angles between the two surgical groups during the 12 daily functional tasks. However, significant differences were reported in level and slope walking activities during pre-swing phase (at around 60% of the gait cycle). The navigated group had significantly higher knee joint angles during pre swing suggesting a more vigorous push off into swing phase and a more ‘normal’ gait cycle. The two surgical groups were sub divided into males and females for the strength test. The female navigated group recorded a significantly greater hamstring (p = 0.03) and quadriceps (p = 0.003) moment. There was no significant difference in hamstring or quadriceps moments between the navigated and conventional male groups. The knee kinematics and moment data suggests that the navigated group had an improved functional outcome. However the difference in the post-operation function of the two groups remains minimal despite the better alignment achieved using navigation.
Over the last two decades, anatomic anterior cruciate ligament (ACL) reconstructions have gained popularity, while the use of extraarticular reconstructions has decreased. However, the biomechanical rationale behind the lateral extraarticular sling has not been adequately studied. By understanding its effect on knee stability, it may be possible to identify specific situations in which lateral extraarticular tenodesis may be advantageous. The primary objective of this study was to quantify the ability of a lateral extraarticular sling to restore native kinematics to the ACL deficient knee, with and without combined intraarticular anatomic ACL reconstruction. Additionally, we aimed to characterise the isometry of four possible femoral tunnel positions for the lateral extraarticular sling. Eight fresh frozen hip-to-toe cadavers were used in this study. Navigated Lachman and mechanised pivot shift examinations were performed on ACL itact and deficient knees. Three reconstruction strategies were evaluated: Single bundle anatomic intraarticular ACL reconstruction, Lateral extraarticular sling, Combined intraarticular ACL reconstruction and lateral extraarticular sling. After all stability tests were completed, we quantified the isometry of four possible femoral tunnel positions for the lateral extraarticular sling using the Surgetics navigation system. A single tibial tunnel position was identified and digitised over Gerdy's tubercle. Four possible graft positions were identified on the lateral femoral condyle: the top of the lateral collateral ligament (LCL); the top of the septum; the ideal tunnel position, as defined by the navigation system's own algorithm; and the actual tunnel position used during testing, described in the literature as the intersection of the linear projections of the LCL and the septum over the lateral femoral condyle. For each of the four tunnel positions, the knee was cycled from 0 to 90® of flexion and fiber length was recorded at 30® intervals, therefore quantiying the magnitude of anisometry for each tunnel position. Stability testing: Sectioning of the ACL resulted in an increase in Lachman (15mm, p = 0.01) and mechanised pivot shift examination (6.75mm, p = 0.04) in all specimens compared with the intact knee. Anatomic intraarticular ACL reconstruction restored the Lachman (6.7mm, p = 3.76) and pivot shift (−3.5mm, p = 0.85) to the intact state. With lateral extraarticular sling alone, there was a trend towards increased anterior translation with the Lachman test (9.2mm, p = 0.50). This reconstruction restored the pivot shift to the intact state. (1.25mm, p = 0.73). Combined intraarticular and extraarticular reconstruction restored the Lachman (6.2mm, p = 2.11) and pivot shift (−3.75mm, p = 0.41) to the intact state. There was no significant difference between intraarticular alone and combined intraarticular and extraarticular reconstruction. (p = 1.88) Isometry: The ideal tunnel position calculated by the navigation system was identified over the lateral femoral condyle, beneath the mid-portion of the LCL. The anisometry for the ideal tunnel position was significantly lower (5.9mm; SD = 1.8mm; P<0.05) than the anisometry of the actual graft position (14.9mm; SD = 4mm), the top of the LCL (13.9mm; SD = 4.3mm) and the top of the septum (12mm; SD = 2.4mm). In the isolated acute ACL deficient knee, the addition of a lateral extraarticular sling to anatomic intraarticular ACL reconstruction provides little biomechanical advantage and is not routinely recommended. Isolated lateral extraarticular sling does control the pivot shift, and may be an option in the revision setting or in the lower demand patient with functional instability. Additionally, the location of the femoral tunnel traditionally used results in a significantly more anisometric graft than the navigation's system mathematical ideal location. However, the location of this ideal tunnel placement lies beneath mid-portion of the fibers of the LCL, which would not be clinically feasible.
Controversies about the management of injuries to the soft tissue structures of the posteromedial corner of the knee and the contribution of such peripheral structures on rotational stability of the knee are of increasing interest and currently remain inadequately characterised. The posterior oblique ligament (POL) is a fibrous extension off the distal aspect of the semimembranosus that blends with and reinforces the posteromedial aspect of the joint capsule. The POL is reported to be a primary restraint to internal rotation and a secondary restraint to valgus translation and external rotation. Although its role as a static stabiliser to the medial knee has been previously described, the effect of the posterior oblique ligament (POL) injuries on tibiofemoral stability during Lachman and pivot shift examination in the setting of ACL injury is unknown. The objective of this study was to quantify the magnitude of tibiofemoral translation during the Lachman and pivot shift tests after serial sectioning of the ACL and POL. Eight knees were used for this study. Ligamentous constraints were sequentially sectioned in the following order: ACL first, followed by the POL. Navigated mechanised pivot shift and Lachman examinations were performed before and after each structure was sectioned, and tibiofemoral translation was recorded. Lachman test: There was a mean 6.0 mm of lateral compartment translation in the intact knee (SD = 3.3 mm). After sectioning the ACL, translation increased to 13.8 mm (SD = 4.6; P<0.05). There was a nonsignificant 0.7 mm increase in translation after sectioning the POL (mean = 14.5 mm; SD = 3.9 P>0.05). Mechanised pivot shift: Mean lateral compartment translation in the intact knee was −1.2 mm (SD = 3.2 mm). Sectioning the ACL caused an increase in anterior tibial translation (mean = 6.7 mm; SD = 3.0 mm; P<0.05). No significant change in translation was seen after sectioning the POL (mean = 7.0 mm, SD = 4.0 mm; P>0.05). Sectioning the POL did not significantly alter tibiofemoral translation in the ACL deficient knee during the Lachman and pivot shift tests. This study brings into question whether injuries to the POL require reconstruction in conjunction with ACL reconstruction. More studies are needed to further characterise the role of the injured POL in knee stability and its clinical relevance in the ACL deficient and reconstructed knee.
Fractures of the femoral head are a challenging problem. The most often performed head preserving procedure worldwide is closed reduction and insertion of cannulated screws under fluoroscopic control. The use of navigation is still experimental in general trauma since rigid reference markers must be attached to all fragments. The examined system (Surgix®, Tel Aviv, Israel) is a fluoroscopy based image analysing system. It consists of a workstation and X-ray opaque markers in surgical tools. When the tool is visible in a C-arm shot a trajectory is displayed as additional layer in the image to serve as guidance for the surgeon. Forty synthetic femurs (Synbone®, Malans, Switzerland) were used and placed inside foam to simulate the soft tissue of the thigh. The models were equipped with 4.5mm radio-opaque markers at the fovea capitis femoris as target point. The aim was to bring the tip of a K-wire as close as possible to the target point entering the bone at the lateral base of the greater trochanter in a center-center position. Twenty were done under image guidance and 20 were operated the conventional way. Outcome measures included the accuracy (the distance between the tip of the wire and the target in a CT), the number of guide wire insertions, procedure duration, radiation exposure and learning curve. In the image guided group optimal guide wire placement was accomplished on first pass in 65% of the cases as compared to 5% in the conventional group (p = < 0.0001). The average number of trial and error was significantly lower in the guided group (1.7 vs. 5.8, p = < 0.0001). Consequently the average duration of the guided procedure was significantly shorter (p = 0.0008) along with radiation exposure time reduced by over 70% (p = 0.0002). The guidance system hit averaged 5.8 mm off target as compared to 5.3 mm for the freehand method (p = 0.3319). Image based guidance significantly shortened the procedure, reduced the radiation exposure and the number of trials without changing the surgeons workflow and can be used in trauma cases were reference marker based navigation is not applicable.
Computer assisted surgery (CAS) is used in trauma surgery to reduce radiation and improve accuracy but it is time consuming. Some trials for navigation in small bone fractures were made, but they are still experimental. One major problem is the fixation of the dynamic reference base for navigation. We evaluated the benefit of a new image based guidance-system (Surgix®, Tel Aviv, Israel) for fracture treatment in scaphoid bones compared to the conventional method without navigation. The system consists of a workstation and surgical devices with embedded radio opaque markers. These markers as well as the object of interest must be on the same C-arm shot. If a tool is detected in an image by the attached workstation additional information such as trajectories are displayed in the original fluoroscopic image to serve the surgeon as aiming device. The system needs no referencing and no change of the workflow. For this study 20 synthetic hand models (Synbone®, Malans, Switzerland) were randomised in two groups. Aim of this study was a central guide-wire placement in the scaphoid bone, which was blindly measured by using postoperative CT-scans. Significant distinctions related to the duration of surgery, emission of radiation, radiation dose, and trials of guide-wire positioning were observed. By using the system the surgery duration was with 50 % shortened (p = 0.0054) compared to the conventional group. One reason might be the significant reduction of trials to achieve a central guide-wire placement in the bone (p = 0.0032). Consequently the radiation exposure for the surgeon and the patient could be shortened by reduction of radiation emission (p = 0.0014) and radiation dose (p = 0.0019). By using the imaged based guidance system a reduction of surgery duration, radiation exposure for the patient and the surgeon can be achieved. By a reduced number of trials for achieving a central guide-wire position the risk of weakening the bone structure can be minimised as well by using the system. The system seems helpful where navigation is not applicable up to now. The surgical workflow does not have to be chanced.
There is great interest to provide repeatable and durable treatments for arthritis localized to one or two compartments in the cruciate-ligament intact knee. We report a series of efforts to develop and characterize an implant system for partial knee resurfacing. We studied distal femoral morphology and found that the sagittal-plane relationships between the condylar and trochlear surfaces are highly variable (Figs 1 and 2). In response, we report the design of a multi-compartmental system of implants intended to anatomically resurface any combination of compartments (Fig 3). Finally, we report the results of a pilot fluoroscopic study of the in vivo knee kinematics in patients who received medial, medial plus patellofemoral and bi-condylar knee arthroplasty. The kinematic results suggest these treatments provide a stable knee with intact cruciate ligament function. This work shows various partial knee resurfacing treatments have the potential to provide excellent knee mechanics and clinical outcomes.
Knee prostheses retrieved at revision often show patterns and severity of damage neither seen nor predicted from standard wear simulator testing. We hypothesized that this is because these implants are exposed to combinations of loads and motions that are more damaging than the simple loading profiles utilized in laboratory testing. We examined the magnitude, direction, and combination of forces and moments acting on the knee during various activities in order to guide the future development and testing of high-performance knee replacements. In vivo data from five patients with instrumented tibial implants were obtained from an open database (www.orthoload.com). We determined the direction and magnitude of forces and moments that the knee experiences during the following common physiologic activities: stair descent, stair ascent, deep knee bend, one leg stance, and walking. In order to capture the loading pattern, we investigated the three component forces and moments acting on the knee at several high demand points for each of these activities. The e-tibia data were compared to the loading profiles used in conventional laboratory testing (ISO 14243-1).Introduction
Methods
Carpal tunnel syndrome (CTS) is said to be a condition of middle-aged women. Our experience is that it more commonly occurs in older people and also in a younger working population. The aim of this study is to describe the epidemiology of CTS requiring carpal tunnel decompression (CTD). Over a 10.5 year period 3073 CTD were performed on 2309 patients aged 15 – 93 years. This included all public, private and ACC funded cases in our region. During this period we had no restriction to access to CTD as all publicly funded cases were performed under local anaesthetic in a day surgery unit. Neurophysiological studies were performed pre-operatively by the same neurophysiologist. Population data from the national census (2006) was used to calculate the annual incidence of patients requiring CTD for each 5 year age band. There were 1418 females (61.4%) and 891 males (38.6 %). In contrast females comprised 116 of 306 (37.8%) patients who had their surgery funded by ACC. The mean age at surgery was 45 years for ACC cases compared with 56 years for non-ACC funded cases. The incidence of males having surgery funded by ACC was 1.7 times higher than females. There was a biphasic pattern in females with an incidence of 3.0/1000 at age 50–54 years, and a second higher peak of 3.1 to 3.4/1000 from 70 to 5 years. Males had a linear increase in incidence peaking at 3.1/1000 for age 65–69 years declining slightly to 2.8/1000 for age 70–85 years. The incidence was significantly higher in females than males overall (1.8 v 1.1/1000) and in patients under 65 years (1.4 v 0.8/1000). In patients over 65 years there was no significant difference in incidence (female 2.8, male 2.5/1000). Within our region, the incidence of surgically treated carpal tunnel syndrome increases with age. The highest rates are seen over the age of 70 in women and 65 years in men with no significant difference in rates between men or women over 65 years.
Total hip arthroplasty (THA) is regarded as one of the most successful surgeries in medicine. However, recent studies have revealed that ideal acetabular cup implantation is achieved less frequently than previously thought, as little as 50% of the time. It is well known that malalignment of the acetabular component in THA may result in dislocation, reduced range of motion, or accelerated wear. This study reports accuracy of a tactile robotic arm system to ream the acetabulum and impact an acetabulur cup compared to manual instrumentation. 12 fresh frozen cadaveric acetabulae were pre-operatively CT scanned and 3D templating was used to plan the center of rotation, and anteversion and inclination of the cup. Each specimen received THA, six prepared manually and six prepared with robotic arm guidance. Tactile, visual, and auditory feedback was provided through robotic guidance as well as navigated guided reaming and cup impaction. The robotic guidance constrained orientation of instruments thus constraining anteversion, inclination, and center of rotation for reaming, trialing, and final cup impaction. Post-operative CT scans were taken of each specimen to determine final cup placement for comparison to the pre-operative plans.INTRODUCTION
METHODS
This study was undertaken to evaluate the early results of a new implant system - the metaphyseal sleeve - in revision total knee replacement. The femoral and tibial metaphyseal sleeves are a modular option designed to deal with metaphyseal bone loss and achieve cementless fixation over a relatively wide area in the metaphysis. Over three years, femoral and/or tibial metaphyseal sleeves were implanted in 104 knees in 103 patients (54 male and 49 female). The clinical notes and radiographs of these patients were reviewed retrospectively. Thirty one patients had revision for infection, 42 for aseptic loosening, and 31 for instability, pain or stiffness. Eighty nine knees were revised as a single stage and 15 were done as two stage procedure. Minimum follow up is 12 months (average 18.5 months).Introduction
Methods
The royal victoria hospital is a tertiary trauma centre receiving pelvic injury referrals for a population of 1.7 million. The use of ilio-sacral screw fixation with low anterior frame stabilisation has been adopted as the principle treatment for unstable pelvic ring injuries in our institution. We aim to describe our practice and outcomes following the use of percutaneous screw fixation of the pelvis. The review included standardised assessment of health-related quality of life (SF-36) as well as the Iowa pelvic score and Majeed pelvic injury outcome scores. Data was also collected on associated injuries, post-operative complications, nerve injury and pain scores. A total case series of 45 patients undergoing percutaneous ilio-sacral screw fixation following traumatic pelvic injury were identified over a 5 year period. Of these 23 were contactable to follow-up or responded to questionnaire review. The mean follow up was 680 days (range 151–1962). The mean age was 33 (range 18–57). The mean SF-36 physical and mental scores were 38 and 46 respectively. The mean Majeed score was 69 and Iowa pelvic score was 65. The mean pain score was 3.5 (range 0–7). There were no incidences of deep infection, post-operative PE or nerve injury related to screw insertion. Patients with isolated pelvic injuries performed better on outcome scoring however the low SF-36 scores highlight the severity of pelvic injuries
Stem geometry is known to influence the outcome in THA; however it is unknown whether the material properties, stiffness in particular can influence the stem stability and outcome. The aim of this study was to measure the influence of stem material properties on micromotion and migration using Roentgen Stereophotogrammetric Analysis (RSA) system. 41 patients were implanted with a collarless polished tapered (CPT) femoral stem (Zimmer, Warsaw, Indiana), which was made of either cobalt-chromium (CoCr) (n=21) or stainless steel (n=20). RSA was used to measure dynamically inducible micromotion (DIMM: difference in stem position in going from double-leg stance (DLS) to single leg stance (SLS)), prosthesis bending (difference in the head-tip distance when going from DLS to SLS), and mean migration of the head, tip and the cement restrictor. DIMM and bending were measured at 3 months, migration at 6, 12 and 24 months. All analyses were carried out using SPSS for windows (v.15.0.0, Chicago. IL, USA). Results were reported as mean ± 95% confidence interval (CI) and regarded as significant when p < 0.05.Introduction
Methods
Replacing bone lost as a consequence of trauma or disease is a major challenge in the treatment of musculoskeletal disorders. Tissue engineering strategies seek to harness the potential of stem cells to regenerate lost or damaged tissue. Bone marrow aspirate (BMA) provides a promising autologous source of skeletal stem cells (SSCs) however, previous studies have demonstrated that the concentration of SSCs required for robust tissue regeneration is below levels present in iliac crest BMA, emphasising the need for cell enrichment strategies prior to clinical application. To develop a novel strategy to enrich skeletal stem cells (SSCs) from human BMA, clinically applicable for intra-operative orthopaedic use.Background
Aims
Despite interest, the current rate of day-case anterior cruciate ligament reconstruction (ACLR) in the UK remains low. Although specialised care pathways with standard operating procedures (SOPs) have been effective in reducing length of stay following some surgical procedures, this has not been previously reported for ACLR. We evaluate the effectiveness of SOPs for establishing day-case ACLR in a specialist unit. Fifty patients undergoing ACLR between May and September 2010 were studied prospectively (“study group”). SOPs were designed for pre-operative assessment, anaesthesia, surgical procedure, mobilisation and discharge. We evaluated length of stay, readmission rates, patient satisfaction and compliance to SOPs. A retrospective analysis of 50 patients who underwent ACLR prior to implementation of the day-case pathway was performed (“standard practice group”).Background
Methods
ARMD (Adverse Reaction to Metal Debris) is an increasingly recognised complication of metal on metal hip replacements. The MHRA (Medical and Healthcare Related Devices Agency) have advised a blood cobalt or chromium level above 7 mg/L is a threshold for further investigation, stating that “low levels are reassuring and strongly predict not having an adverse outcome”. Cross-sectional imaging should be performed when levels are above 7 mg/L. We have performed a study investigating the specificity and sensitivity of chromium and cobalt metal ion levels as a screening measure for ARMD. 79 ASR hip replacements were performed at our hospital and 75 (95%) of these underwent a Metal Artefact Reduction Sequence (MARS) MRI scan. All patients (64 hips) who had not undergone revision were invited to take part in this study. 57 patients with 62 hip replacements completed hip and activity scores, had blood cobalt and chromium ion level measurements and 3D-CT to measure acetabular component position. Acetabular component inclination (>50 degrees), small head size (< 51mm) and female gender were significantly correlated with raised chromium (Cr) and cobalt (Co) ion levels. An ARMD was detected using MRI in 18 (29%) of the hips in this study. The incidence of ARMD was significantly higher when chromium concentration was above 7 mg/l (p = 0.02). Chromium ion levels >7 mg/L had a sensitivity of 56% and specificity of 83% for ARMD, and cobalt ion levels >7 mg/L 56% and 76% respectively. 40 patients had cobalt levels <7 mg/L and 33 had chromium levels <7 mg/L, but 8 of these had an ARMD on MRI. All 8 patients had minimal symptoms (Oxford Hip Score ≥ 44 out of 48). The Medicines and Healthcare Products Regulatory Agency (MHRA) has recommended that cobalt and chromium levels be measured in patients with a metal-on-metal hip replacement and cross-sectional imaging performed when these levels are above 7 μg/L. This study has shown that by using this threshold, in patients with this implant combination, the sensitivity and specificity for the detection of ARMD is low and patients with soft tissue disease may be missed. Furthermore the presence of MRI detected ARMD, in the absence of significant clinical symptoms and with metal ion levels <7 μg/L is of concern. MoM implants at risk of failure are associated with raised cobalt and chromium levels. However metal ion analysis alone is not reliable as a screening tool for ARMD, which is often clinically “silent”. We recommend the routine use of MARS MRI as the safest method of ARMD diagnosis in patients with MoM implants.
The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Quantifying the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy. To describe the relative contribution of vessels to anastomoses supplying the anterior knee.Introduction
Aim
We describe the results for the management of chronic osteomyelitis in long bones using a new single stage procedure, the Cardiff technique. Fourteen consecutive patients were treated prospectively. The patients had a mean age of 52; all patients had a mean stay in hospital of 5 days with outpatient dressings. All patients had tibial fractures, 2 were infected non unions. The origin of infection was traumatic in 13 cases and haematogenous in 1 case. This one stage procedure or The Cardiff technique, uses techniques described by both Papineau's 3 stage method and Lautenbach's procedure. It involves removal of all avascular and infected tissue via marginal debridement, opening of the medullary cavity proximally and distally, compartmental debridement and copious saline irrigation. The wound is then packed with Jelonet and kaltostat and fresh dressings applied weekly. The wound is left to heal via secondary intention. There is no routine use of antibiotics. Antibiotics were only used when required, i.e. Clinical evidence of cellulitis or infection. 11 patients healed with no further surgery, no skin grafting, no bone grafting and no flap coverage. Mean time to healing was 5 months; both non unions united giving results similar to other accepted techniques. There were 3 residual infections, 2 due to inadequate debridement which required a single further compartmental debridement (Lautenbach method), 1 had an avascular bone edge requiring further local debridement. We feel this procedure confers the following advantages; minimal surgical insult, early discharge, out patient management, good outcomes and most importantly, high patient satisfaction. It also serves as a reminder that simple wounds do well with simple solutions.
