Cells typically respond to a variety of geometrical cues in their environment, ranging from nanoscale surface topography to mesoscale surface curvature. The ability to control cellular organisation and fate by engineering the shape of the extracellular milieu offers exciting opportunities within tissue engineering. Despite great progress, however, many questions regarding geometry-driven tissue growth remain unanswered. Here, we combine mathematical surface design, high-resolution microfabrication, in vitro cell culture, and image-based characterization to study spatiotemporal cell patterning and bone tissue formation in geometrically complex environments. Using concepts from differential geometry, we rationally designed a library of complex mesostructured substrates (101-103 µm). These substrates were accurately fabricated using a combination of two-photon polymerisation and replica moulding, followed by surface functionalisation. Subsequently, different cell types (preosteoblasts, fibroblasts, mesenchymal stromal cells) were cultured on the substrates for varying times and under varying osteogenic conditions. Using imaging-based methods, such as fluorescent confocal microscopy and second harmonic generation imaging, as well as quantitative image processing, we were able to study early-stage spatiotemporal cell patterning and late-stage extracellular matrix organisation. Our results demonstrate clear geometry-dependent cell patterning, with cells generally avoiding convex regions in favour of concave domains. Moreover, the formation of multicellular bridges and collective curvature-dependent cell orientation could be observed. At longer time points, we found clear and robust geometry-driven orientation of the collagenous extracellular matrix, which became apparent with second harmonic generation imaging after ∼2 weeks of culture. Our results highlight a key role for geometry as a cue to guide spatiotemporal cell and tissue organisation, which is relevant for scaffold design in tissue engineering applications. Our ongoing work aims at understanding the underlying principles of geometry-driven tissue growth, with a focus on the interactions between substrate geometry and mechanical forces.
Thoracic hyperkyphosis (TH – Cobb angle >40°) is correlated with rotator cuff arthropathy and associated with anterior tilting and protraction of scapula, impacting the glenoid orientation and the surrounding musculature. Reverse total shoulder arthroplasty (RTSA) is a reliable surgical treatment for patients with rotator cuff arthropathy and recent literature suggests that patients with TH may have comparable range of motion after RTSA. However, there exists no study reporting the possible link between patient-reported outcomes, humeral retroversion and TH after RTSA. While the risk of post-operative complications such as instability, hardware loosening, scapular notching, and prosthetic infection are low, we hypothesize that it is critical to optimize the biomechanical parameters through proper implant positioning and understanding patient-specific scapular and thoracic anatomy to improve surgical outcomes in this subset of patients with TH. Patients treated with primary RTSA at an academic hospital in 2018 were reviewed for a two-year follow-up. Exclusion criteria were as follows: no pre-existing chest radiographs for Cobb angle measurement, change in post-operative functional status as a result of trauma or medical comorbidities, and missing component placement and parameter information in the operative note. As most patients did not have a pre-operative chest radiograph, only seven patients with a Cobb angle equal to or greater than 40° were eligible. Chart reviews were completed to determine indications for RTSA, hardware positioning parameters such as inferior tilting, humeral stem retroversion, glenosphere size/location, and baseplate size. Clinical data following surgery included review of radiographs and complications. Follow-up in all patients were to a period of two years. The American Shoulder and Elbow Surgeons (ASES) Shoulder Score was used for patient-reported functional and pain outcomes. The average age of the patients at the time of RTSA was 71 years old, with six female patients and one male patient. The indication for RTSA was primarily rotator cuff arthropathy. Possible correlation between Cobb angle and humeral retroversion was noted, whereby, Cobb angle greater than 40° matched with humeral retroversion greater than 30°, and resulted in significantly higher ASES scores. Two patients with mean Cobb angle of 50° and mean humeral retroversion 37.5° had mean ASES scores of 92.5. Five patients who received mean humeral retroversion of 30° had mean lower ASES scores of 63.7 (p < 0 .05). There was no significant correlation with glenosphere size or position, baseplate size, degree of inferior tilting or lateralization. Patient-reported outcomes have not been reported in RTSA patients with TH. In this case series, we observed that humeral stem retroversion greater than 30° may be correlated with less post-operative pain and greater patient satisfaction in patients with TH. Further clinical studies are needed to understanding the biomechanical relationship between RTSA, humeral retroversion and TH to optimize patient outcomes.
The purpose of this study was to compare the clinical outcomes, mortalities, implant survival rates, and complications of total knee arthroplasty (TKA) in patients with or without hepatitis B virus (HBV) infection over at least ten years of follow-up. From January 2008 to December 2010, 266 TKAs were performed in 169 patients with HBV (HBV group). A total of 169 propensity score–matched patients without HBV were chosen for the control group in a one-to-one ratio. Then, the clinical outcomes, mortalities, implant survival rates, and complications of TKA in the two groups were compared. The mean follow-up periods were 11.7 years (10.5 to 13.4) in the HBV group and 11.8 years (11.5 to 12.4) in the control group.Aims
Methods
In this study, we aimed to explore surgical variations in the Femoral Neck System (FNS) used for stable fixation of Pauwels type III femoral neck fractures. Finite element models were established with surgical variations in the distance between the implant tip and subchondral bone, the gap between the plate and lateral femoral cortex, and inferior implant positioning. The models were subjected to physiological load.Aims
Methods
This paper aims to analyze the kinetics of the over-ground wheel-type body weight supporting system (BWS); tendency changes of low extremity joint moment (hip, knee, ankle), 3 axis accelerations of a trunk, cadence and gait velocity as weight bearing level changes. 15 subjects (11 males, 4 females, age:23.63.5, height:170.65.1cm, weight:69.0210.75kg) who had no history of surgery participated. 6 levels (0%, 10%, 20%, 30%, 40% and 50%) of BWS were given to subjects at self-selected gait velocity and kinetic data was calculated using a motion capture system, Vicon® (Vicon, UK).Objective
Method
Management and outcomes of fungal periprosthetic joint infection (PJI) remain unclear due to its rarity. Although two-stage exchange arthroplasty is considered a treatment of choice for its chronic features, there is no consensus for local use of antifungal agent at the 1st stage surgery. The purpose of this study was to evaluate the efficacy of antifungal-impregnated cement spacer in two-stage exchange arthroplasty against chronic fungal PJIs after total knee arthroplasty (TKA). Nine patients who were diagnosed and treated for chronic fungal PJIs after TKA in a single center from January 2001 to December 2016 were enrolled. Two-stage exchange arthroplasty was performed. During the 1st stage resection arthroplasty, amphotericin-impregnated cement spacer was inserted for all patients. Systemic antifungal medication was used during the interval between two stage operations. Patients were followed up for more than 2 years after exchange arthroplasty and their medical records were reviewed.Purpose
Methods
Suture anchor have been used in surgical procedure of tendon or ligament repair. Recently, there has been developed an all suture anchor (soft anchor) which can be used even when the insertion area is narrow. But, the stability of soft anchors due to narrow zone has not been elucidated. This purpose of this study was to investigate stability of soft anchors with respect to their fixation intervals. Polyurethane foams with two different bone densities (10 pcf; 0.16g / cm³, 20 pcf; 0.32g / cm) were used. All suture anchors and conventional suture anchors were fixed at 10mm, 5mm, and 2.5mm intervals. The failure load was measured using a mechanical testing machine.Introduction
Methods
The current study aimed to determine the influence of acetabular coverage and intraarticular pathology on post-operative functional outcomes of arthroscopy for cam type FAI. Based on 762 hip scopes performed by a single surgeon between 2013 and 2016, we excluded patients with previous surgery on the hip, mixed FAI, surgical hip dislocation, and missing outcome scores. From this, 97 hips between the ages 17 and 48 that underwent arthroscopy for cam deformity were identified for analysis. Every patient received a partial capsulotomy, cam resection and either labral repair or resection. Measurements for acetabular coverage consisted of pre-operative lateral edge angle (LCEA) (mean 30°, range: 15.4°–40°) and three-dimensional anterior and posterior acetabular coverages. Intraoperative Beck scores were acquired from operative reports, and Hip Disability and Osteoarthritis Outcome Score (HOOS) was collected pre- and post-operatively. Significant post-operative improvement was found in scores of all categories of the HOOS (p < 0.05). However, improvement in HOOS was not correlated with the LCEA, anterior coverage, or posterior coverage. There was a trend toward lower Beck grades (1–3) resulting in better HOOS outcomes than higher Beck grades (4–5). Also, lower Beck grades showed significantly lower alpha angle (mean = 55.86) than higher grades (mean = 73.48). We showed that cam FAI arthroscopic resection improved patient outcome, and confirmed the relationship between the Beck score and functional outcome. However, functional improvement was not related to acetabular coverage suggesting that the so-called “borderline” dysplasia is not a useful radiographic indicator for surgical management.
The objective of this study was to assess the association between whole body sagittal balance and risk of falls in elderly patients who have sought treatment for back pain. Balanced spinal sagittal alignment is known to be important for the prevention of falls. However, spinal sagittal imbalance can be markedly compensated by the lower extremities, and whole body sagittal balance including the lower extremities should be assessed to evaluate actual imbalances related to falls. Patients over 70 years old who visited an outpatient clinic for back pain treatment and underwent a standing whole-body radiograph were enrolled. Falls were prospectively assessed for 12 months using a monthly fall diary, and patients were divided into fallers and non-fallers according to the history of falls. Radiological parameters from whole-body radiographs and clinical data were compared between the two groups.Objectives
Methods
Clinical and radiological results of total hip arthroplasty (THA) using proximally coated single wedge (PSW) cementless stems are generally excellent. The geometry of cementless stems and the morphology of proximal femurs (Dorr types) provide optimal fit for primary stability and secondary biologic fixation. Because the geometry of PSW shape is designed to be engaged at the metaphysis, cementless PSW stem is not traditionally recommended to Dorr type C femurs with concerns of inadequate implant-host bone contact and the risk of femoral fracture. Nevertheless, previous studies on PSW cementless stems have not examined long-term survivorship according to Dorr types of femur. Paucity of a long-term comparative study makes it difficult to know whether the PSW stem plays a role in Dorr type C femurs or not. We postulated that the PSW stem could achieve stable fixation without increased risk of femoral fracture even in Dorr type C femurs, and demonstrate acceptable long-term results. The aim of this study was to investigate differences of clinical and radiological outcomes of THA using PSW stem according to proximal femoral geometry (Dorr types) in more than a 10-year follow-up. Three hundred and seven primary THA in 247 patients, which was performed with use of a single-designed PSW stem from 1997 to 2003 and was followed up for over 10 years, were included in this retrospective study. According to Dorr's criteria, 89 femora were classified as Type A, 156 as Type B, and 62 as Type C. The patients' mean age at operation was 43.2 years (range, 18.4 – 69.6 years). They were followed-up for an average of 13.2 years (the range, 10.0 – 17.3 years). All of the hips were evaluated clinically and radiologically with special attention to the occurrence of implant loosening and periprosthetic femoral fracture. The mean preoperative Harris hip score (50.4±20.6 points) improved significantly to 95.6±9.0 points at the final follow-ups. The improvements were observed regardless of Dorr types (p<0.001 in all 3 groups). The incidence of thigh pain (p=0.704) was not significantly different among groups. Implant survivorship was 100% in all 3 groups. None of the stems were loosened or revised. No significant differences were observed in osteolysis (p=0.492), pedestal formation (p=0.323), or cortical hypertrophy (p=0.169) among the groups [Fig. 1]. Radiolucent lines less than 2mm in thickness in Gruen zone 4 were observed more in Dorr type C femora than in Dorr type A or B (p=0.003) [Fig. 2]. Spot weld (p<0.001) and stress shielding (p=0.010) of proximal femur were more pronounced in Dorr C type femora than in type A or B [Fig. 3]. The prevalence of intraoperative (p=0.550) or postoperative (p=0.600) femoral fractures were not significantly different among the groups. From over a 10-year follow-up, the PSW stem provided excellent stem survivorship regardless of Dorr type with satisfactory outcomes. The remodeling process around the stem was more pronounced in Dorr type C femur. The present study shows that the PSW stem is a recommendable option for Dorr type C femur.
Alternative bearing surfaces has been introduced to reduce wear debris-induced osteolysis after total hip arthroplasty (THA) and offered favorable results. Large population-based data for total joint surgery permit timely recognition of adverse results and prediction of events in the future. The purpose of this study was to present the epidemiology and national trends of bearing surface usage in primary total hip arthroplasty (THA) in Korea using nationwide database. A total of 30,881 THAs were analyzed using the Korean Health Insurance Review and Assessment Service database for 2007 through 2011. Bearing surfaces were sub-grouped according to device code for national health insurance claims and consisted of ceramic-on-ceramic (CoC), metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM). The prevalence of each type of bearing surface was calculated and stratified by age, gender, hospital type, primary payer, and procedure volume of each hospital. The number of primary THAs increased by 25.2% from 5,484 in 2007 to 6,866 in 2011. The average age of the entire study population was 58.1 years, and 53.5% were male [Table 1]. CoC was the most commonly used bearing surface (76.7%), followed by MoP (11.9%), CoP (7.3%), and MoM (4.1%). The distribution of bearing surfaces was identical to that in the general population regardless of age, gender, hospital type, and primary payer [Table 2]. The mean age of patients that received hard-on-hard bearing surfaces (CoC and MoM) was significantly younger than that of patients receiving hard-on-soft bearing surfaces (CoP and MoP) (56.9 years vs. 62.6 years). During the study period, 55.1% of THAs that used a hard-on-hard bearing surface were performed in males, while 53.0% of THAs that used a hard-on-soft bearing surface were performed in females. The order of prevalence of bearing surfaces was identical in low- and medium-volume hospitals (CoC was first, MoP was second, CoP was third, and MoM was fourth). The mean hospital charges did not differ according to the bearing surface used, with the exception of CoP, which was associated with a lower mean hospital charge. There were no changes in the distribution of bearing surfaces in each year between 2007 and 2011. Overall, the percentage of THAs that used CoC bearing surfaces increased substantially from 71.6% in 2007 to 81.4% in 2011, while the percentage that used CoP, MoP, and MoM decreased significantly [Fig. 1]. One of the reasons for the dominant usage of hard-on-hard bearing surfaces may be that the principal diagnosis of primary THAs and the patient age group distribution in Korea differ from those in other countries. The most common indication for primary THA is osteonecrosis of the femoral head in Korea. In contrast, the majority of primary THAs are performed for osteoarthritis in Western countries. The choice of bearing surface may be affected by many factors, including the nation's medical delivery system, payment type, disease pattern, and age distribution of patients that undergo THA. In future, the results of a large-scale nationwide study on primary THAs using CoC bearing surfaces in Korea will be reported.
Proper positioning of the baseplate and optimal screw placement are necessary to avoid loosening or failure of the glenoid component in RTSA. Several in vitro and anatomic studies have documented ideal number, size, length and angulation of baseplate screws. However, such fixation can often be tenuous, as the anatomy of scapula bone varies. Furthermore, it can be difficult to identify regions with the best bone stock intraoperatively even though surgeons have an understanding of scapular anatomy with potential screw trajectories in mind. This often leads to variable screw lengths and angulations in the clinical setting. The purpose of this study was to measure optimal screw lengths and angles to reach ideal regions in cadaveric scapulae and to compare the clinical experiences of three surgeons with each other and against a cadaveric model with screw lengths and angulations. Seven cadaveric scapulae were used as the template for optimal screw angulation and length for baseplate implantation. Total 21 cases (seven cases of each 3 surgeons) of reverse total shoulder arthroplasty using the Aequalis®-Reversed shoulder prosthesis (Tornier, France) were included. Measurement of screw angulation was done on the AP and axillary views to account for the superior-inferior and the antero-posterior angulations, respectively. The screw lengths used on each scapula was recorded prior to insertion in cadavers and retrieved from the operative records in clinical cases. Screws directed anteriorly and superiorly were recorded as positive values while posteriorly and inferiorly directed screws were designated negative values. The significant differences in degrees of screw angulation and screw lengths among the 3 surgeon groups were calculated using the ANOVA, with the p value at 0.05. The Mann-Whitney U test was performed to evaluate the cadaver group against the surgeon groups.Introduction
Materials and Methods
A cell-based tissue-engineered construct can be employed for treating meniscal lesions occurring in the non-vascularized inner two-thirds. The objective of this study was to test the hypothesis that both pre-differentiation of human bone marrow derived stromal cells (hBMSCs) into chondrogenic lineage before cell seeding and platelet-rich plasma (PRP) pretreatment on a PLGA mesh scaffold enhances the healing capacity of the meniscus with hBMSCs-seeded scaffolds PRP of 5 donors was mixed and used for the experiments. The woven PLGA mesh scaffold (VicrylTM, Ethicon) measuring 20×8 mm (thickness, 0.2 mm) was prepared. The scaffolds were immersed into 1,000 μl of PRP and were centrifuged at 150g for 10 min. Then, the scaffold was flipped 180° and the same procedure was done for the other side. After washing, the scaffolds were soaked into 1,000 μl of DMEM media. hBMSCs from an iliac crest of 10 patients after informed consent and approval of our IRB were induced into chondrogenic differentiation with chondrogenic media containing 10 ng/ml rhTGF-ß3 in 1.2% alginate bead culture system for 7 days. Then, 2×105 hBMSCs were recovered, seeded onto the scaffold, and cultured under dynamic condition. Based on the presence of pre-differentiation into chondrogenic lineage and the PRP pretreatment, 4 study groups were prepared. (no differentiation without PRP, no differentiation with PRP, chondrogenic differentiation without PRP, chondrogenic differentiation with PRP) Cell number for each cell-seeded scaffold was determined at 24 hours after seeding. Then, scaffolds were placed between human meniscal discs and were implanted subcutaneously in nude mice for 6 weeks (n=10 per group).Background
Methods
Total knee arthroplasty (TKA) is a well proven surgical procedure. Squat and gait motions are common activities in daily life. However, squat motion is known as most dissatisfying motion in activities in daily life after total knee arthroplasty (TKA). Dissatisfaction after TKA might refer to muscle co-contraction between quadriceps and hamstrings. The purposed of this study was to develop squat and gait simulation model and analyses the contact mechanics and quadriceps and hamstring muscle stability. We hypothesized that squat model shows larger contact forces and lower hamstring to quadriceps force ratio than gait model. Squat motion and gait model were simulated in musculoskeletal simulation software (AnyBody Modeling System, AnyBody Technology, Denmark). Subject-specific bone models used in the simulation were reconstructed from CT images by Mimics (Materialize, Belgium). The lower extremity model was constructed with pelvis, femur, tibia, foot segments and total knee replacement components: femoral component, tibial insert, tibial tray, and patella component [Fig.1]. The muscle model was consisted of 160 muscle elements. The TKR components used in this study are PS-type LOSPA Primary Knee System (Corentec Co., Ltd, Republic of Korea). Force-dependent kinematics method was used in the simulation. The model was simulated to squat from 15° to 100° knee flexion, in 100 frames. Gait simulation model was based on motion capture and force-plate system. Motion capture and force-plate data were from grand challenge competition dataset.Introduction
Materials and Methods
The mid- or long-term results of acetabular revision total hip arthroplasty (THA) in Korea are rare. The purpose of this study is to report the mid-term radiographic results (> 5 years) of acetabular revision THA with porous-coated cementless Trilogy® cup (Zimmer, Warsaw, IN, USA). Between 1999 and 2010, 77 patients (79 hips) had underwent acetabular revision THA with Trilogy® cup. Eight patients (8 hips) were excluded due to death before 5-year follow-up, and 22 patients (23 hips) were excluded due to less than 5-year follow-up or follow-up loss. Forty-seven patients (48 hips) were included in our study. The mean age was 57.9 years (range, 36 to 76 years) and the mean follow-up was 9.8 years (range 5.0 to 16.2 years). The causes of revision were aseptic loosening in 40 hips, and septic loosening in 8 hips, respectively. Both acetabular and femoral revisions were performed in 14 hips and isolated acetabular revision was done in 34 hips. Preoperetive acetabular bone defect according to Paprosky classification was; 1 in type I, 6 in IIA, 11 in IIB, 9 in IIC, 15 in IIIA, and 6 in IIIB.Introduction
Materials and Methods
To compare the clinical and radiological results between internal fixation using the proximal femoral nail system and bipolar hemiarthroplasty in reverse oblique intertrochanteric hip fracture in elderly patients. From January 2005 to July 2012, we reviewed 53 patients who had been treated surgically for reverse oblique intertrochanteric fracture and been followed up on for a minimum of 2 years. The patients, all over 70 years old, were divided into two groups for retrospective evaluation: one group was treated with open reduction and internal fixation using the proximal femoral nail system (31 cases), and the other group was treated with bipolar hemiarthroplasty (22 cases).Purpose
Materials and Methods
Mechanically assisted crevice corrosion (MACC) of head-neck modular taper junctions is prevalent in virtually all head neck tapers in use today. To date, no clear in vitro tests of design, material or surgical elements of the modular taper system have been reported that show which factors principally affect MACC in these tapers. Possible elements include seating load, head-neck offset, surface roughness, taper engagement length, material combination, angular mismatch, and taper diameter. The goals of this study were to use an incremental fretting corrosion test method1 to assess the above 7 elements using a design of experiments approach. The hypothesis is that only one or two principal factors affect fretting corrosion. A 27-2 design of experiment test (7 factors, ¼ factorial, n=32 total runs, 16 samples per condition per factor) was conducted. Factors included: Assembly Force (100, 4000N), Head Offset (1.5, 12 mm), Taper Locking Position (Mouth, Throat), Stem Taper Length (0.44, 0.54 in), Stem Taper Roughness (Ground, Ridged), Taper Diameter (9/10, 12/14), and Stem Material (CoCrMo, Ti-6Al-4V). The heads were CoCrMo coupled with taper coupons (DePuy Synthes, Warsaw, IN). Test components were assembled wet and seated axially with 100 or 4000N assembly force. The assemblies were immersed in PBS and potentiostatically held at −50mV vs. Ag/AgCl. Incremental cyclic loads were applied vertically to the head at 3Hz until a 4000N maximum load was reached (See Fig. 1). Fretting currents at 4000 N cyclic load were used for comparisons while other parameters, including onset load, subsidence, micromotion and pull off load were also captured. Statistical analysis was performed using Pareto charts and Student's T-tests for single factor comparisons (P < 0.05 was statistically significant).Introduction
Methods
We evaluated the clinical and radiographic outcomes of cementless bipolar hemiarthroplasty using rectangular cross-section stem for femoral neck fracture in elderly patients more than 80 years of age with osteoporosis. 76(cemented 46, cementless 30) bipolar hemiarthroplasties for femur neck fracture were performed in elderly patients more than 80 years old. The mean follow-up period was 4.3 years (2 to 7 years). The Harris hip score at last follow-up and pre-postoperative daily living activity scale according to Kitamura methods were analyzed clinically. The radiological results were assessed using stability of femoral stem and other complications were evaluated. Results: At last follow-up, there were no significant differences of Harris hip score and daily living activity between two groups. Stem loosening and instability were not observed in cementless arthroplasty. There were 18 cases of osseous fixation in radiologic study. There were 1 case of dislocation and 1 case of superficial infection in cemented arthroplasty and 1 case of deep infection in cementless arthroplasty.Purpose
Material and Methods
Rotational alignment is important for the long-term success and good functional outcome of total knee arthroplasty (TKA). While the surgical transepicondylar axis (sTEA) is the generally accepted landmark on the distal femur, a precise and easily identifiable anatomical landmark on the tibia has yet to be established. Our aim was to compare five axes on the proximal tibia in normal and osteoarthritic (OA) knees to determine the best landmark for determining rotational alignment during TKA. One hundred twenty patients with OA knees and 30 without knee OA were recruited for the study. Computed tomography (CT) images were obtained and converted through multiplanar reconstruction so the angles between the sTEA and the axes of the proximal tibia could be measured. Five AP axes were chosen: the line connecting the center of the posterior cruciate ligament(PCL) and the medial border of the patellar tendon at the cutting level of the tibia (PCL-PT), the line from the PCL to the medial border of the tibial tuberosity (PCL-TT1), the line from the PCL to the border of the medial third of the tibia (PCL-TT2), the line from the PCL to the apex of the tibia (PCL-TT3), and the AP axis of the tibial prosthesis along with the anterior cortex of the proximal tibia (anterior tibial curved cortex, ATCC).Background
Methods
Although vertebroplasty is very effective for relieving acute pain from an osteoporotic vertebral compression fracture, not all patients who undergo vertebroplasty receive the same degree of benefit from the procedure. In order to identify the ideal candidate for vertebroplasty, pre-operative prognostic demographic or clinico-radiological factors need to be identified. The objective of this study was to identify the pre-operative prognostic factors related to the effect of vertebroplasty on acute pain control using a cohort of surgically and non-surgically managed patients. Patients with single-level acute osteoporotic vertebral compression fracture at thoracolumbar junction (T10 to L2) were followed. If the patients were not satisfied with acute pain reduction after a three-week conservative treatment, vertebroplasty was recommended. Pain assessment was carried out at the time of diagnosis, as well as three, four, six, and 12 weeks after the diagnosis. The effect of vertebroplasty, compared with conservative treatment, on back pain (visual analogue score, VAS) was analysed with the use of analysis-of-covariance models that adjusted for pre-operative VAS scores.Objectives
Patients and Methods
To observe the follow-up results of standard cemented bipolar hemiarthroplasty with double loop and tension band wiring technique for treatment of unstable intertrochanteric hip fractures in elderly patients with osteoporosis. From May 2000 to May 2006, 86 cemented bipolar hemiarthroplasties were performed in elderly patients who had unstable intertrochanteric fractures. The mean age at the time of surgery was 82 years old. The average follow-up period were 5.3 years. We evaluated post-operative results after operation by clinical and radiographic methods.Purpose
Materials and Methods
To perform comparative analysis between the results of internal fixation using proximal femoral nail system and bipolar hemiarthroplasty in pantrochanteric hip fracture in elderly patients. From January 2006 to February 2012, we reviewed 43 patients, who were treated surgically for pantrochanterichip fractures, with a minimum of 2 years follow up. The patient's age was older than 70 year old. The patients were divided into three groups and evaluated, retrospectively. The fracture reduction were regarded as satisfactory in S-OR-IF group(17 cases) and unsatisfactory in US-OR-IF group(9 cases) and the other group was treated with bipolar hemiarthroplasty (BHA group, 17 cases.)Purpose
Materials and Methods
Theoretically, improved material properties of new alumina matrix composite (AMC) material, Delta ceramics, are expected to decrease concerns associated with pure alumina ceramics and allow manufacturing thinner liners and consequent larger heads. However, limited short-term clinical results are available and mid-term results of these effects are unclear. (1) Does AMC material decrease the rate of ceramic fracture and noise, concerns of previous-generation ceramics, following change of material properties? (2) Does the possible use of larger heads consequent to manufacturing thinner liners decrease dislocation rate and affect inguinal pain? (3) Do any other complications associated with the use of AMC ceramics occur?Background
Questions/Purposes
In this study, we investigated the long-term clinical results and survivorship of minimally invasive unicompartmental knee arthroplasty (UKA) by collecting cases that have been implanted for >10 years ago. Medial UKA on 180 cases in 142 patients was performed over a period of 1 year after the first introduction of minimally invasive UKA from January 2002 to December 2002. Among these, 166 cases in 128 patients who underwent Oxford phase 3 medial UKA using the minimally invasive surgery, with the exclusion of 14 cases including 10 cases of follow-up loss and 4 cases of death, were selected as the subject. The mean age of the patients at the time of surgery was 61 years, and the duration of the follow-up was minimum 10 years. All the preoperative diagnosis was osteoarthritis of the knee joint. Clinical and radiographic assessments were measured by the Knee Society clinical rating system, and the survival analysis was confirmed by the Kaplan–Meier method with 95% confidence interval (CI).Background
Methods
To identify the modes of failure after total knee arthroplasty (TKA) in patients ≤ 55 years of age and to compare with those ≥ 56 years of age in patients who underwent revision TKA. We retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between those ≤ 55 years of age and those ≥ 56 years of age. The age at the time of primary surgery was ≤ 55 years in 30 patients (31 knees) and ≥ 56 years in 210 patients (225 knees).Purpose
Materials and Methods
A stem extension improves fixation stability of a tibial component. We need caution not to contact the tibial cortex with an offset adaptor. A symmetric tibial stem design often requires the component's re-positioning with negative effects. Therefore, the objective of this study was to validate clinical efficacy of a tibial baseplate with asymmetric stemmed position (TB-ASP) using aligning outlier rate. We hypothesized that TB-ASP design will be better aligned without unessential offset adaptor than a tibial baseplate with symmetric stemmed position (TB-SSP). TB-ASP was designed based on the anthropometric standard model (58 female cadavers, 54.7±11.4 years)(Figure 1.). To validate the stem position, 3D bone models of 20 OA patients (71.8±7.2 years) was reconstructed. All virtual surgery has done by one surgeon with consistent surgical procedure for the analysis criteria. An analysis of TB-ASP's aligning outlier was proceeded by following steps; 1) aligning tibial baseplate to the line from medial 1/3 tuberosity to the center of PCL, 2) selecting tibial baseplate's size for maximal bone coverage without problematic overhang, 3) trying to displace tibial baseplate and stem extension(120mm long) not to contact tibial cortex. A case invading tibial cortex was considered to be an outlier. The ratio using offset adaptor was compared to those of TB-SSP. Statistical analysis was performed using paired t-test.Introduction
Methods
3-D Printing with direct metal tooling (DMT) technology was innovatively introduced in the field of surface treatment of prosthesis to improve, moreover to overcome the problems of plasma spray, hopefully resulting in opening the possibility of another page of coating technology. We presumed such modification on the surface of Co-Cr alloy by DMT would improve the ability of Co-Cr alloys to osseointegrate. We compared the in vitro and in vivo ability of cells to adhere to DMT coated Co-Cr alloy to that of two different types of surface modifications: machined and plasma spray(TPS). We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines of human were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and avb3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups.Introduction
Method
The purpose of this study is to evaluate the clinical outcomes and and radiological findings of primary total hip arthroplasty(THA) performed by using cemented polished femoral stem. We retrospectively reviewed 91 hips (84 patients) that had undergone primary THA with cemented polished femoral stem after follow-up more than 10 years. The mean age at surgery was 57 years old (47 to 75). Mean follow up period was 12. 8 years(10.1 to 14). Clinical evaluation was performed using Harris hip score. The radiographic evaluation was performed in terms of the cementing technique, including of subsidence within the cement mantle, radiolucent lines at the cement-bone or cement-stem interface, cortical hypertrophy, and calcar resorption.Purpose
Materials and Methods
To evaluate the effectiveness of post-operative pain management using the intra-operative peri-articular injection(PAI) and/or electromyography (EMG)-guided preoperative femoral nerve block (FNB) in total knee arthroplasty(TKA). From March 2013 to February 2014, 90 knees which underwent primary TKA by one surgeon were included in our study. The patients were classified into three groups; a single injection FNB with an EMG guide (Group I, 30 knees), intra-operative PAI (Group II, 30 knees) and both FNB and PAI (Group III, 30 knees). Pain at rest and moving was evaluated by Visual Analogue Scale (VAS) at postoperative 0, 4, 8, 24 and 48 hours. Postoperative range of motion, time to walking, total blood loss, amount of opioid consumption and complications were compared in each group.Purpose
Materials and Methods
To measure the vitamin D level of the patients who received total knee arthroplasty (TKA) and evaluate the effect of vitamin D level on the results of TKA. From February 2012 to January 2013, 151 female patients (204 knees) who underwent primary TKA by one surgeon were included in our study. Preoperative vitamin D level was measured and analyzed the relationship between that and preoperative Visual Analogue Scale (VAS), and Knee Society Knee Score (KS) and Function Score (FS). Thirty-nine patients (39 knees) who received unilateral TKA and could be followed up more than 1 year after operation were evaluated for the relationship between vitamin D level and postoperative VAS, KS and FS, and Western Ontario and McMaster Universities Arthritis Index (WOMAC) score.Purpose
Materials and Methods
The NexGen® legacy posterior stabilized (LPS)-Flex total knee system (Zimmer, Warsaw, IN) is designed to provide 150° of flexion following total knee arthroplasty (TKA). But, recent reports found a high incidence of loosening of the femoral component related to the deep flexion provided. We evaluated 9- to 12-year clinical and radiological follow-up results after NexGen® LPS-Flex TKA. A retrospective evaluation was undertaken of 209 knees in 160 patients (21 males, 139 females) who were followed up for more than 9 years after Nexgen®LPS-Flex TKA. Evaluations included preoperative and postoperative range of motion(ROM), Knee Society(KS) knee score, function scores, tibiofemoral angle and assessment of postoperative complications.Purpose
Materials and Methods
The purpose of this study was to compare the clinical and radiological results after total knee arthroplasty(TKA) with PCL sacrificing (PCS) Medial Pivot Knee (MPK) and PCL Substituting (PS) Nexgen® LPS. One hundred twenty knees in 80 patients after TKA with PCS ADVANCE® MPK (Group I) and 116 knees in 85 patients with PS Nexgen® LPS (Group II) were retrospectively evaluated. All the patients were followed up for more than 6 years. The evaluations included preoperative and postoperative range of motion (ROM), tibiofemoral angle, Knee Society (KS) knee and function score, Hospital for Special Surgery (HSS) knee score, WOMAC score and postoperative complications.Purpose
Materials and Methods
To establish relative fixation strengths of a single lateral locking plate, a double locking plate, and a tibial nail in treatment of proximal tibial extra-articular fractures. Three groups of composite tibial synthetic bones consisting of 5 specimens per group were included; lateral plating (LP) using a LCP-PLT (locking compression plate-proximal lateral tibia), double plating (DP) using a LCP-PLT and a LCP-MPT (locking compression plate-medial proximal tibia), and intramedullary nailing (IN) using an ETN (expert tibial nail). To simulate a comminuted fracture model, a gap osteotomy measuring 1 cm was cut 8 cm below the joint. For each tibia, a minimal preload of 100N was applied before loading to failure. A vertical load was applied at 25mm/min until tibia failure.Background
Methods
Although gradual bone transport may provide a large-diameter bone, complications are common with the long duration of external fixation. To reduce such complications, a new technique of bone transport with a locking plate has been done for tibial bone defect. In 13 patients (mean age, 38.9 years) of chronic osteomyelitis or traumatic bone defect, segmental transport was done using external fixator with a locking plate. In surgical technique, a locking plate was fixed submuscularly, holding the proximal and distal segments. Then, the external fixator for transport was fixed without contact of the locking plate. After docking, 2 or 3 screws were fixed at the transported segment through the plate holes. At the same time, the external fixator was removed.Background
Methods
To evaluate outcome after cementless bipolar hemiarthroplasties using a standard(tapered, rectangular) stem for the treatment of above type A2 fractures in elderly patients. We reviewed the records of 37 patients who underwent bipolar hemiarthroplasty between February 2006 and Feburuary 2010 in our hospital who were followed for more than two years after surgery. The mean patient age was 73.5 years old (range 64∼88 years old). 16 patients were men, and 21 patients were women. We evaluated the results by analyzing operation time, amount of bleeding, recovery of walking ability, complications and radiologic findings.Purpose
Material and methods
A seventy-five-year-old female patient presented with pain and deformity of her left leg of three days duration. Hybrid THRA has been done 11 years ago at her left hip for the treatment of osteoarthritis. Massive osteolysis and pathologic fracture were observed on plain radiograph (Fig. 1). Revision THRA using an allograft prosthesis composite (APC) was planned for solution of extensive bone loss of the proximal femur. Surgical exposure was performed through extended trochanteric osteotomy with the patient supine. Step-cut osteotomy was done at the remained proximal part of host femur to make match with the distal part of APC. Meticulous removal of granulation tissues and remaining cement was done. As Acetabular cup was stable, 60 mm sized high-walled polyethylene liner was exchanged. Calcar reconstruction prosthesis was cemented into a proximal femoral allograft measuring 15 cm and cement at the vicinity of the step-cut osteotomy was removed for later bony union at interface. After solid fixation of APC with cement, the distal half of APC was cemented with the host femur. Step-cut osteotomy was wired and autogenous bone grafts from the greater trochanter were added at the interface. Leg length and stability were rechecked using a standard necked 28 mm metal head and reduction was done stably. Greater trochanter was fixed over the trimmed proximal allograft with multiple wiring and paper-thin host femur was enveloped around the femoral allograft using absorbable sutures. Following insertion of the closed suction drainage drains, closure was done as routine fashion and healing of the wound was uneventful (Fig. 2). An abduction brace was applied post operatively for a period of four weeks. Crutch walking with partial weight bearing was started at four weeks and crutch protection was applied for a period of six months. Incorporation of allograft with the host bone was observed on two-year follow-up radiographs. At seven-year follow-up, the patient walks well with a mild limp, and Harris score is 90. We report on a seven-year follow-up case of revision THRA with APC with references (Fig. 3).
To analyze the effectiveness of a vancomycin impregnated calcium sulfate cement bead insertion after debridement (of) an acute-immediate stage infected hip arthroplasty. Between 2002 and 2008, 13 patients with documented acute-immediate stage infection of hip arthroplasty were reviewed and followed for at least two years postoperatively(average 4.3 years). The preoperative and postoperative clinical and radiologic findings and blood laboratory work were checked. All cases were performed through retention of the implant and massive debridement and saline irrigation. After that a vancomycin impregnated calcium sulfate cement beads was inserted.Purpose
Materials and Methods
Recent reports about the excellent clinical results of unicondylar knee arthroplasty (UKA; also known as unicompartmental knee arthroplasty), by the minimally invasive approach, have encouraged the adoption of the surgical technique. However, friction between metallic prosthetic components resulting from polyethylene wear may result in the development of metallosis and the use of metal implants has become a huge issue in the worlds recently. Here, we report a case in which a patient underwent UKA and developed metallosis in soft tissues and bone adjacent to an implanted artificial joint three years postoperatively.
The posterior-stabilized knee prosthesis is designed specifically to provide the posterior stability to a knee arthroplasty when PCL is deficient or has to be sacrificed. Posterior dislocation of such prosthesis is rare but dreaded complication. There are several causes of postoperative dislocation such as malposition of the prosthesis, preoperative valgus deformity, a defect of the extensor mechanism and overwidening of the flexion gap. Posterior-stabilized rotating-platform mobile-bearing knee implants have been widely used to further improve the postoperative range of motion by incorporation of the post and cam mechanism to improve the posterior roll back during flexion and to overcome the wear and osteolysis problems due to significant undersurface micromotion of posterior-stabilized fixed-bearing knees. But, spin-out or rotatory dislocation of the polyethylene insert can occurs as result of excessive rotation of the rotating platform accompanied by translation of the femur on the tibia after mobile-bearing total knee arthroplasty, but that is very rare. Here, authors describe an unusual case of acute 180° rotatory dislocation of the rotating platform after posterior dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty. A 71-year-old male with knee osteoarthritis underwent a TKRA using posterior-stabilized mobile-bearing prosthesis. The posterior dislocation of the total knee arthroplasty occurred 5 weeks postoperatively(Fig. 1). We underwent closed reduction of posterior dislocated total knee arthroplasty resulting in a complete 180° rotatory dislocation of the rotating platform (Fig. 2). He was treated with open exploration and polyethylene exchange with a larger component. This case illustrates that dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty can occur with valgus laxity, cause 90° spin-out of the polyethylene insert and closed reduction attempts may contribute to complete 180° rotatory dislocation of the rotating platform. Special attention needs to be paid to both AP and lateral view to ensure that the platform is truly reduced and not just rotated 180° as was in this case.
No study compared the clinical results of the posterior-stabilized mobile-bearing knee with those of nonposterior-stabilized mobile-bearing knee in the same patients. The purpose of this study was to examine whether the clinical and radiographic results, range of motion, patients satisfaction, and complication rates would be better in the knees with a posterior-stabilized mobile-bearing knee than in the knees with a nonposterior-stabilized mobile-bearing knee. One hundred and fourteen patients (mean age, 67.9 years) received a nonposterior-stabilized mobile-bearing knee prosthesis in one knee and a posterior-stabilized mobile-bearing knee prosthesis in the contralateral knee. Seven patients were men, and 107 were women. At the time of each follow-up (mean, 7.3 years; range, seven to 7.6 years), the patients were assessed clinically and radiographically.Background
Methods
Total Knee Arthroplasty (TKA) is a durable procedure which allows most patients to achieve a satisfactory functional level, but there can be instability under stressful conditions. Instability is one cause of early revision, often due to misalignment or inadequate ligament balancing. Persistent instability may cause elevated polyethylene wear. Lower levels of instability may cause patient discomfort with certain stressful activities. Hence quantifying instability may have an important role in the functional evaluation of TKA. Several previous studies showed that accelerometers have advantages in kinematic studies including low cost, ease of application, and application to any activity. The aim of this study was to demonstrate the use of an accelerometer attached to the anterior of the tibia, as an evaluation of knee stability of TKA patients. It was postulated that accelerations between TKAs and normal controls will be different, which could indicate abnormal TKA kinematics involving instability, especially for high intensity activities. We tested 38 TKA knees in 27 patients, in the age range of 50–80 years, with a minimum follow up of 6 months; and 25 knees in 16 shoulder patients, who had no known knee pathology as age-matched controls. A tri-axial accelerometer was firmly attached to the anterior proximal tibia to measure 3-axis accelerations with a sample rate of 100 Hz. Four activities were tested; Starting with the test leg, walk 3 steps then come to a sudden stop Take one step forward with the non-tested leg and make a tight 90∗∗∗∗∗ turn towards the non- tested knee direction Sit down for 3–4 seconds then stand back up Step up on a 7″ inches high box with the test leg, followed by the non-test leg. Then step down from the box with the test leg, followed by the non-test leg. During the activities, the patients responded to a questionnaire on instability and pain for each activity. For each test at the time of foot impact, there was a high/low peak acceleration, the peak-to-valley being taken as the indicator. The mean total magnitude of the acceleration was compared between the TKA and control groups in the anterior-posterior direction using the Student's t-test. Statistical significance was at p-value < 0.05.INTRODUCTION
METHODS & MATERIALS
It has been suggested that the wear of ultra-high molecular weight polyethylene (UHMWPE) in total hip replacement is substantially reduced when the femoral head is ceramic rather than metal. However, studies of alumina and zirconia ceramic femoral heads on the penetration of an UHMWPE liner in vivo have given conflicting results. The purpose of this study was to examine the surface characteristics of 30 alumina and 24 zirconia ceramic femoral heads and to identify any phase transformation in the zirconia heads. We also studied the penetration rate of alumina and zirconia heads into contemporary UHMWPE liners. The alumina heads had been implanted for a mean of 11.3 years (8.1 to 16.2) and zirconia heads for a mean of 9.8 years (7.5 to 15). The mean surface roughness values of the explanted alumina heads (Ra 40.12 nm and Rpm 578.34 nm) were similar to those for the explanted zirconia heads (Ra 36.21 nm and Rpm 607.34 nm). The mean value of the monoclinic phase of two control zirconia heads was 1% (0.8% to 1.5%) and 1.2% (0.9% to 1.3%), respectively. The mean value of the monoclinic phase of 24 explanted zirconia heads was 7.3% (1% to 26%). In the alumina group, the mean linear penetration rate of the UMWPE liner was 0.10 mm/yr (0.09 to 0.12) in hips with low Ra and Rpm values (13.22 nm and 85.91 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.13 mm/yr (0.07 to 0.23) in hips with high Ra and Rpm values (198.72 nm and 1329 nm, respectively). This difference was significant (p = 0.041). In the zirconia head group, the mean linear penetration rate of the UHMWPE liner was 0.09 mm/yr (0.07 to 0.14) in hips with low Ra and Rpm values (12.78 nm and 92.99 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.12 mm/yr (0.08 to 0.22) in hips with high Ra and Rpm values (199.21 nm and 1381 nm, respectively). This difference was significant (p = 0.039). The explanted zirconia heads which had a minimal phase transformation had similar surface roughness and a similar penetration rate of UHMWPE liner as the explanted alumina head.
Although total knee arthroplasty (TKA) has been a reliable procedure providing durable pain relief, polyethylene (PE) wear remains a major limitation of the long-term success of TKA. One potential method of lowering PE wear in TKA is to use oxidized zirconium (OxZr)-bearing surface. Although wear simulating testing of an OxZr counter surface of femoral component produced less PE wear and fewer particles than did cobalt-chrome (Co-Cr) counter surface of femoral component [1–4], this finding has not been demonstrated in vivo to our knowledge. We measured in vivo PE wear by isolating and analyzing PE wear particles in synovial fluid from wellfunctioning TKA [5]. The purpose of the current study was to determine the size, shape, and amount of PE wear particles isolated from synovial fluid of patients who underwent a bilateral simultaneous TKA prosthesis, but different materials of femoral components. We performed a bilateral simultaneous TKA in 100 patients (200 knees) who received an OxZr femoral component in one knee and a Co-Cr femoral component in the other. Mean age was 55.6 (44–60) years. Synovial fluid was obtained from 28 patients (56 knees) who had undergone a simultaneous bilateral TKA under completely sterile conditions at one or two years after the operation. Randomization to an OxZr or Co-Cr femoral component was accomplished with use of a sealed study number envelope, which was opened in the operating room before the skin incision had been made. After the opening the randomization envelope, the first knee received prosthesis indicated by the envelope (OxZr or Co-Cr component) and the contralateral (second TKA) knee received the other prosthesis (OxZr or Co-Cr component). All operations were performed by one surgeon using the same design of total knee prosthesis: Genesis II (Smith and Nephew, Memphis, Tennessee). Only the material of the femoral component differed between two groups. The preoperative diagnosis was osteoarthritis in all patients. Preoperative and post operative KS and HSS knee scores, KS functional scores and UCLA activity scores were evaluated. The amount of polyethylene wear particles in the aspirated synovial fluid sample was analyzed by thermogravimetic analysis (TGA) using a TGA instrument (TGA/SDTA 84le model, Mettler Toledo CO., Greifensee, Switzerland). The weight of the sample solution was measured before and after removing the organic content by heating the sample solution. The sample solution was casted onto petri dishes. The petri dish was covered and kept in a dry oven at 60°C for 2 days. While the sample solution was kept in a dry oven for 2 days, a small hole was made on the cover of the petri dish to allow water to evaporate slowly for 2 days. After this procedure, the cover of petri dish was removed and TGA sample was dried at 60°C for another 2 days. After the sample was completely dried out, the dried sample was measured using analytical balance. TGA was used to determine the weight change profiles of polyethylene subject to heating under a nitrogen atmosphere. The nitrogen flow rate was kept constant at 50mL per minute. TGA data were taken at heating rate as 5°C per minute in the temperature range of 20° to 1000°C. The weight loss data were recorded as a function of time and temperature using special software in computer. When the temperature reached to the point of decomposition of the sample, the sample started to lose weight. By calculating the weight of the sample around the temperature which led to start to decomposition, real amount of polyethylene in the sample was measured. The size and shape of PE particles were examined using scanning electron microscopy (JSH-6360A model, Jeol Co., Tokyo, Japan). The samples were coated using a platinum sputtering machine for 20 sec. ANOVA, nonparametric chi square test, nonpaired t-test and Mann-Whitney U-test were used for statistical analyses. Differences of P<
0.05 were considered statistically significant. Mean preoperative KS (27.5 vs 27.2 points) scores, HSS (51.1 vs 51.2 points) knee scores, KS functional scores (55.4 vs 55.4 points) and UCLA activity scores (2.8 vs 2.8 point) were not significantly different between two groups. Mean postoperative KS (93 vs 92 points), HSS knee scores (90 vs 89 points), KS functional scores (78 vs 78 points), and UCLA activity scores (7.8 vs 7.8) were not significantly different. Mean weight of the polyethylene particles was 0.0219 g (SD, 0.0058) in the Co-Cr femoral component groups and it was 0.0214 g (SD, 0.005) in the OxZr group. This difference was not significant (P=0.711139, paired t-test). The size of particles was not different between the two groups. Also, shape of particles was not different between the two groups. Under the condition and the duration of this study in this specific group of patients, TKA with OxZr or Co-CR femoral knee component had excellent clinical and radiographic outcomes with no osteolysis. While the wear simulator test in vitro demonstrated significant decrease in PE particles in the knees with an OxZr femoral component, our study in vivo revealed that total particle weight, size, and shape of PE wear particles were similar in the knees with an OxZr femoral component and in those with a Co-Cr femoral component.
We aimed to analyze the clinical results of the patients according to joint line change who underwent navigation assisted cruciate ligament retention type mobile bearing total knee arthroplasty. From September 2004 to January 2006, cruciate ligament retention type mobile bearing total knee arthroplasties using navigation system(Orthopilot®, Aesculap) were performed for 50 knees in 45 patients (2 men, 43 women). The mean follow up period was 46(39~55) months and the mean age was 65. There was one case with rheumatoid arthritis and all other were degenerative arthritic cases. All surgeries were performed using navigation system. Proximal tibia resection was performed at the sclerotic level of medial tibial plateau. The distance from the lowest point of lateral tibial plateau (registered point) to the proximal resection plane was measured. Clinical outcome were compared between joint line elevation with more than 3 mm(20cases) and less than 3mm (30cases). The mean joint line elevation was 1.93 mm (range −1~5mm). There were no significant difference in the clinical results according to the joint line change (p>
0.05). It may be suggested that the change of joint line in the range of −1 to 5mm in cruciate ligament retention type mobile bearing total knee arthroplasty result in satisfactory clinical outcome.
As the proximal femoral bone is generally compromised in failed hip arthroplasty, achievement of solid fixation with a new component can be technically demanding. Recent studies have demonstrated good short-term clinical results after revision total hip arthroplasty using modular distal fixation stems, but, to our knowledge, none have included clinical follow-up of greater than 5 years. The purpose of this study was to report the clinical and radiographic outcomes assessed 5 to 10 years following revision total hip arthroplasty with a modular tapered distal fixation stem. We retrospectively evaluated 50 revision total hip arthroplasties performed using a modular tapered distal fixation stem Between December 1998 and November 2003. There were 15 men (16 hips) and 34 women (34 hips) with a mean age of 59 years (range, 36 to 80 years). The index operation was the first femoral revision for 46 hips, the second for 3 hips, and the fifth for 1 hip. According to the Paprosky classification, 5 femoral defects were Type II, 31 were Type IIIA, and 14 were Type IIIB. An extended trochanteric osteotomy was carried out in 24 (48%) of the 50 hips. Patients were followed both clinically and radiographically for a mean of 7.2 years. The mean Harris hip score improved from 54 points preoperatively to 94 points at the time of the latest follow-up. The mean stem subsidence was 1.5mm. Three stems subsided more than 5 mm, but all have stabilized in their new positions. During follow-up, a total of 4 hips required additional surgery. One hip had two-stage re-revision due to deep infection, one had liner and head exchange for alumina ceramic head fracture, and the other two underwent isolated cup re-revision because of aseptic cup loosening and recurrent dislocation, respectively. No repeat revision was performed due to aseptic loosening of the femoral component. Complications included 6% intraoperative fractures, 4% cortical perforations, and 4% dislocations. There were no stem fractures at the modular junction. The medium-term clinical results and mechanical stability obtained with this modular tapered distal fixation stem were excellent in these challenging revision situations with femoral bone defects.
