Aims

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings.

Aims

Simultaneous bilateral total knee arthroplasty (TKA) has been used due to its financial advantages, overall resource usage, and convenience for the patient. The training model where a trainee performs the first TKA, followed by the trainer surgeon performing the second TKA, is a unique model to our institution. This study aims to analyze the functional and clinical outcomes of bilateral simultaneous TKA when performed by a trainee or a supervising surgeon, and also to assess these outcomes based on which side was done by the trainee or by the surgeon.

Introduction

Our objective is to describe early and midterm results with the use of a new knee prosthesis as an articulating spacer in planned two-stage management for infected total knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a completed 2-stage revision.

Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate.

The purpose of this study was to assess survivorship, complications and functional outcomes at a minimum 10 years after the constrained tripolar liners used in our institute.

We retrospectively identified 111 patients who had 113 revision tripolar constrained liners between 1998 and 2008. Eighty-nine were revised due to recurrent dislocations, 11 for pseudotumor with dysfunctional abductors, and 13 for periprosthetic infection with loss of soft tissue stabilizers. All patients had revision hip arthroplasty before the constrained liner was used: 13 after the first revision, 17 after the second, 38 after the third, and 45 had more than 3 revisions. We extracted demographics, implant data, rate of dislocations and incidence of other complications. Kaplan Meier curves were used to assess dislocation and failure for any reason. WOMAC was used to assess quality of life.

At 10 years, the survival free of dislocation was 95.6% (95%CI 90- 98), and at 20 years to 90.6% (95% CI 81- 95.5). Eight patients (7.1%) had dislocations of their constrained liners: 1 patient had simultaneous periprosthetic infection identified at the time of open reduction, and 1 patient sustained stem fracture 3 months prior to the liner dislocation. At 10 years, the survival to any further surgery was 89.4% (95% CI 82–93.8), and at 20 years, this was 82.5 (95% CI 71.9–89.3). Five patients (4.4%) had deep infection: 4 of these had excision arthroplasty due to failure to control infection, while 1 patient was treated successfully with debridement, exchange of mobile components and intravenous antibiotics. Two patients (1.8%) had dissociated rings that required change of liner, ring and head. Two patients (1.8%) had periprosthetic femoral fractures that were treated by revision stems and exchange of constrained liners. The mean WOMAC functional and pain scores were 66.2 and 75.9 of 100, respectively.

Constrained tripolar liners in our institute provided favourable results in the long term for recurrent dislocation hip arthroplasty with dysfunctional hip stabilizers. Infection in these patients can prove to be difficult to treat due to their poor soft tissue conditions from repeated surgeries. Comparing long terms results from other types of constrained liners is essential to evaluate these salvage liners.

A large proportion of wait times for primary total knee (TKA) and hip (THA) arthroplasty is the time from primary care referral to surgical consultation. To our knowledge, no study has investigated whether a referral Oxford Knee or Hip Score (OKHS) could be used to triage non-surgical referrals appropriately. The primary purpose of the current study was to determine if a referral OKHS has the predictive ability to discriminate when a knee or hip referral will be deemed conservative as compared to surgical by the surgeon during their first consultation, and to identify an OKHS cut-off point that accurately predicts when a primary TKA or THA referral will be deemed conservative.

We retrospectively reviewed all consecutive primary TKA and THA consultations from a single surgeon's tertiary, high volume practice over a three-year period. Patients with a pre-consultation OKHS, BMI < 4 1, and no absolute contraindication to TJR were included. Consultation knees/hips were categorized into two groups based on surgeon's decision, those that were offered TJR during their first consolation (surgical) versus those that were not (conservative). Baseline demographic data and OKHS were abstracted. Variables of interest were compared between cohorts using the exact chi-square test and Wilcoxon rank-sum test. Spearman's rank correlation coefficients were used to measure association between pre-consult OKHS and the surgeon's decision. A receiver operator characteristic (ROC) curve analysis was used to calculate the area under the curve (AUC) and to identify a cut-off point for the pre-operative OKHS that identified whether or not a referral was deemed conservative. TKA and THA referrals were analyzed separately.

The study included 1,436 knees (1,016 patients) with a median OKS of 25 (IQR 19–32) and 478 hips (388 patients) with a median OHS of 22 (IQR 16–29). Median pre-consultation OKHS demonstrated clinically and statistically significant differences between the surgical versus conservative cohorts (p 32 (sensitivity=0.997, NPV=0.992) and for hips is OHS >34 (sensitivity=0.997 NPV=0.978). ROC analysis identified severable potential lower OKHS thresholds, depending on weight of prioritization of sensitivity, specificity, and NPV.

Referral OKS and OHS demonstrate good ability to discriminate when a primary TKA or THA referral will be deemed non-surgical versus surgical at their first consultation in a single surgeon's practice. Multiple potential effective OKHS thresholds can be applied as a tool to decrease wait times for primary joint arthroplasty. However, a cost analysis would aid in identifying the optimal cut-off score, and these findings need to be externally validated before they can be broadly applied.

High complication rates and poor outcomes have been widely reported in patients undergoing revision of large head metal-on-metal arthroplasty. A previous study from our centre showed high rates of dislocation, nerve injury, early cup loosening and pseudotumor recurrence. After noting these issues, we implemented the following changes in surgical protocol in all large head MOM revisions: One: Use of highly porous shells in all cases. Two: Use of largest femoral head possible. Three: Low threshold for use of dual mobility and constrained liners when abductors affected or absent posterior capsule. Four: Use of ceramic head with titanium sleeve in all cases. Five: Partial resection of pseudotumor adjacent to sciatic and femoral nerves.

The purpose of the present study is to compare the new surgical protocol above to our previously reported early complications in this group of patients

We specifically looked at (1) complications including reoperations, (2) radiologic outcomes, and (3) functional outcomes. Complication rates after (Group 1), and before (Group 2) modified surgical protocol were compared using Chi-square test, assuming statistical significance p < 0 .05.

Major complications occurred in 4 (8.3%) of 48 patients who had modified surgical technique, compared to 12 (38%) of 32 revisions prior to modification (p < 0 .05). Two hips of 48 (4.17%) endured dislocations in Group 1, compared to 9 of 32 (28%) in Group 2 (p < 0 .05). Four patients of 48 had repeat revision in Group 1: 2 for recurrence of pseudotumor, 1 for dislocation, and 1 for infection, compared to 6 patients who had 7 repeat revisions of 32 patients in Group 2: 3 for acetabular loosening, 3 for dislocation, and 1 for recurrence of pseudotumor (p=0.1). None of 48 revisions in Group 1 had acetabular loosening, compared to 4 of 32 in Group 2 (p=0.02). Two patients had nerve injury in Group 2, compared to none in Group 1 (p=0.16). The mean WOMAC pain score was 87.1 of 100 and the function score was 88.4 of 100 in Group 1, compared to a mean WOMAC pain score of 78 of 100 (p=0.6) and a function score of 83 of 100 in Group 2 (p=0.8).

Modification of the surgical techniques described in the introduction has resulted in a significant decrease in complications in revision of large head MOM total hips. We continue to use this protocol and recommend it for these difficult cases.

Introduction

The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions.

Introduction

The practice of overlapping surgery has been increasing in the delivery of orthopaedic care, aiming to provide efficient, high-quality care. However, there have been concerns about the safety of this practice. The purpose of this study is to examine safety and efficacy of a model of partially overlapping surgery that we termed “the swing room” in practice in primary hip and knee arthroplasty.

Background

Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate.

Background

High complication rates and poor outcomes have been widely reported in patients undergoing revision of large head metal-on-metal arthroplasty. A previous study from our center showed high rates of dislocation, nerve injury, early cup loosening and pseudotumor recurrence. After noting these issues, we implemented the following changes in surgical protocol in all large head MOM revisions: 1. Use of highly porous shells in all cases 2. Use of largest femoral head possible 3. Low threshold for use of dual mobility and constrained liners when abductors affected or absent posterior capsule 4. Use of ceramic head with titanium sleeve in all cases 5. Partial resection of pseudotumor adjacent to sciatic and femoral nerves.

Background

Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes.

Background

Delay in access to primary total hip (THA) arthroplasty continues to pose a substantial burden to patients and society in publicly funded healthcare systems. The majority of strategies to decrease wait times have focused on the time from surgical consult to surgery, however a large proportion of total wait time for these patients is the time from primary care referral to surgical consultation. Prioritization scoring tools and patient reported outcome measures are being used in an attempt to ration limited resources in the face of increasing demand. However, to our knowledge, no study has investigated whether a referral Oxford Hip Score (OHS) could be used to triage non-surgical referrals appropriately, in an effort to increase timely access to specialists for patients that are candidates for total joint replacement (TJR).

Purpose

Dislocation after revision total hip is a common complication. The purpose of this study was to assess whether a large femoral head (36/40mm) would result in a decreased dislocation rate compared to a standard head (32mm).

Purpose

There is a postulated association between increased serum metal ions and pseudotumour formation in patients with metal-on-metal hip replacements. The primary aim of this study was to assess the prevalence of pseudotumour in 31 asymptomatic patients with a large femoral head (LFH) metal-on-metal hip implant. This was compared to the prevalence of pseudotumour in 20 matched asymptomatic patients with a hip resurfacing (HRA) and 24 matched asymptomatic patients with a standard metal-on-polyethylene (MOP) total hip. A secondary objective was to assess possible correlation between increased serum metal ions and pseudotumour formation

Purpose

Measurements of patellar kinematics are essential to investigate the link between anterior knee pain following knee arthroplasty and patellar maltracking. A major challenge in studying the patellofemoral (PF) joint postoperatively is that the patellar component is only partially visible in the sagittal and close-to-sagittal radiographs. The narrow angular distance between these radiographs makes the application of conventional bi-planar fluoroscopy impossible. In this study a methodology has been introduced and validated for accurate estimation of the 3D kinematics of the PF joint post-arthroplasty using a novel multi-planar fluoroscopy approach.

Purpose

The outcome following isolated liner exchange for revision knee arthroplasty, while an attractive option for its simplicity, has a mixed outcome reported in the literature. We report our experience in patients who had a minimum of two years follow-up.

Purpose

The purpose of this study was to compare and evaluate the cost-effectiveness of the MIS Anterolateral Approach to that of the MIS Posterolateral and MIS Direct Lateral Approach.

Purpose: The purpose of this study was to evaluate the clinical effectiveness and outcomes of the ‘abductor sparing’ MIS Anterolateral approach (MIS Watson Jones/G3) in comparison to the MIS Direct Lateral and MIS Posterolateral approaches in primary total hip arthroplasty.

Method: A multicentre, prospective, randomized controlled trial was designed to evaluate for the superiority of the new MIS Anterolateral approach (MIS Watson Jones/ G3). The sample size calculation was performed for alpha .05, power .90, to evaluate for effect size 0.5 in WOMAC using repeated measures analyses with baseline WOMAC as covariate. A total of 156 patients consented to participate in the trial and patients were assigned to MIS Antero-lateral approach or alternate MIS approach (MIS Direct Lateral or MIS Posterolateral). Patients were subjected to standardized anaesthetic and perioperative management protocols and were evaluated at standardized intervals to evaluate endpoints of early recovery (3 months) as well as endpoints of 12 and 24 months respectively. The primary outcome of interest was WOMAC, however secondary outcomes included SF-36, as well as parameters of health resource utilization and complications. Univariate and multivariate analyses were perfomed.

Results: Patient groups were found to be similar at baseline with regards to demographics and baseline quality of life outcomes (p> .05). Multivariate and repeated measures analyses demonstrated no superiority of the MIS Anterolateral approach on outcomes of WOMAC and other quality of life measures in comparison to MIS Direct Lateral and MIS Posterolateral approaches (p> .05). Health care resource utlization was also similar with length of stay, blood transfusion requirements and complications (p> .05).

Conclusion: Our multicentre, prospective, randomized clinical trial demonstrates that the MIS Anterolateral approach is not superior to alternate MIS surgical approaches when evaluating outcomes of quality of life, complications, and health resource utilization. Surgeons should consider these outcomes, complications, and other relevant advantages and disadvantages of select surgical approaches when deciding on a technique for use in their orthopaedic practice.

Purpose: Between 1 and 2% of knee arthroplasties are complicated by infection with its associated patient morbidity. Two stage revision remains the gold standard with the minimum interval considered acceptable between the two stages as 6 weeks, but in some cases can be considerably longer depending on the patients’ clinical response to the first stage and intravenous antibiotics. The interval between the 2 stages is to allow eradication of the causative organism, however, this can result in considerable morbidity for the patient. Patients often have a poor range of movement, instability and considerable discomfort during this time and as a result have poor mobility. Further complications can be encountered at the time of the 2nd stage with considerable scarring of the soft tissues, in part secondary to the lack of mobilisation. Traditionally, spacers which are non-articulating have been used, however, problems of instability, scarring and bone erosion have been reported in the literature. The Prostalac knee spacer constitutes an antibiotic loaded acrylic cement body with a metal on polyethylene surface and enables the patient to undergo rehabilitation in the interval between the 2 stages and may also help maintain soft tissue planes as a result. Previous published results with a mean follow up of 48 months suggest the spacer is just as successful at eradicating infection (91%) as other techniques. The aim of this study is to review 119 patients with a minimum follow up of 5 years.

Method: The Prostalac Knee spacer has 2 components, a femoral and a tibial. Each are made of antibiotic-loaded acrylic cement with a small articulation of metal on polyethylene. The spacers are made from moulds so that a component of a suitable size and thickness could be made. This was a retrospective review of 119 consecutive patients. The inclusion criteria included all patients who had undergone a 2 stage revision with the Prostalac Knee spacer who had more than 5 years of follow up. Patients were assessed using the WOMAC, SF-12, Oxford Knee Score and the Knee Society Score.

Results: Thirteen patients (10.9%) out of a total of 119 had recurrence of infection. This gives an overall rate of control of infection of 89%. Of the 46 patients who completed the outcome score questionnaires with more than 5 years follow up, the mean WOMAC score was 65.9, Oxford Knee score was 61, SF-12 (physical component) was 35.7, SF-12 (mental component) was 54.8.

Conclusion: Although the Prostalac components include polyethylene and metal, they do not seem to have a detrimental impact on the rate of control of infection since our results were similar to those previously reported with other best practice techniques. It is our impression that the Prostalac functional spacer allows earlier pain free mobilisation, allowing the potential for earlier hospital discharge. The savings obtained from earlier hospital discharge greatly outweighing the increased cost of the Prostalac functional spacer system.

Purpose: Subchondral cortical and trabecular bone mineral density (BMD) may increase and/or decrease during different stages of osteoarthritis (OA) disease progression. 2D in-vivo imaging studies examining direct associations between increased proximal tibial BMD and knee OA offer conflicting results, which may be due to the inherent limitations of 2D BMD imaging tools. Our objective was to compare existing and novel 3D imaging techniques for distinguishing subchondral bone properties in OA and normal cadaveric tibiae.

Method: Eight intact cadaver knees from five donors (4M:1F; age: 77+/−10) were repositioned and scanned three times using QCT (0.5mm isotropic resolution, 0.15mSv dosage). BMD was assessed using

computed tomography absorptiometry (CT-OAM) which uses maximum intensity projections to assesses peak density values within subchondral bone, and

Average BMD at normalized depths of 0–2.5mm, 2.5–5.0mm, and 5.0–10mm from the surface were assessed using CT-TomasD. Regional analyses were performed consisting of:

medial/lateral (M/L) BMD ratio, and

Each bone was assessed for OA using a modified-KL scoring system: Normal (mKL=0); Early-OA (1–2); and Late-OA (3–4).

Results: OA was identified in four compartments of three tibiae (1 late OA+valgus, 1 late OA+varus, 1 early OA+neutral). Larger density differences between OA and normal knees were noted using CT-TOMASD compared with CT-OAM. CT-TomasD demonstrated that the two knees with late OA demonstrated M/L BMD ratios differing by more than 3.4 SD compared with normals, with peak cores higher than normals across all depths. The knee with early OA and neutral alignment demonstrated M/L ratios less than normals while core differences were highest proximally, with density becoming lower than normals with increasing depth.

Conclusion: CT-TomasD demonstrated larger differences between OA and normal subjects when compared with CT-OAM differences. This may be due to CT-OAM primarily assessing peak density within the thin subchondral cortical endplate; a region demonstrating fairly uniform peak densities within a limited range.

Purpose: Giant cell tumour (GCT) of the distal radius is associated with high local recurrence rates unless the tumour is aggressively resected, which often leaves a significant skeletal defect. The purpose of this study is to compare the functional outcomes of two commonly used reconstructive techniques, vascularised free fibular transfer (VFF) and non-vascularised structural iliac crest transfer (NIC).

Method: Patients treated for giant cell tumour of the distal radius in either Vancouver or at Mount Sinai Hospital, Toronto were identified in the prospectively collected databases maintained in each centre. Twenty-seven patients were identified, 14 of whom underwent VFF transfer as their primary procedure. The two groups were comparable for age, sex and tumour grade. Functional outcomes were assessed with TESS, MSTS, DASH and the Ankle Osteoarthritis Scale.

Results: Fourteen patients were included in the VFF group, 13 of which were performed as the primary index procedure, one followed prior cementation. Thirteen patients underwent NIC, one followed prior cementation. Two local recurrences occurred in the VFF group and one in NIC group, all treated with local excision. In the VFF group three patients underwent further surgery for cosmesis, hardware removal and tendon release respectively. One is scheduled for future surgery for tendon release. In the NIC group two patients suffered infections requiring debridement, one of which ultimately went on to require free fibular transfer. This patient’s results were included in the NIC group as this was the index procedure. Functional scores showed no differences between the two groups on any of the parameters studied for the upper limb (Mann-Whitney test). The Ankle osteoarthritis scale had a median score of 9% for the six patients on which it was available.

Conclusion: Both VFF and NIC are effective surgical techniques that result in a well-functioning wrist arthrodesis. VFF may be more useful where there is a significant skin defect from previous interventions. We were unable to demonstrate any difference in functional scores between VFF and NIC.

Purpose: Chondral injuries of the knee are commonly seen at arthroscopy, yet there is no consensus on the most appropriate treatment method. However, untreated cartilage injury predisposes to osteoarthritis contributing to pain and disability. For cell-based cartilage repair strategies, an ex-vivo expansion phase is required to obtain sufficient numbers of cells needed for therapy. Although recent reports demonstrated the central role of oxygen for the function and differentiation of chondrocytes, little is known of the effect of physiological low oxygen concentrations during the expansion of the cells and whether this alters their chondrogenic capacity.

Method: Initial studies of chondrocyte expansion were performed in mature mice, with cells expanded at either atmospheric oxygen tension (21%) or 5% 02 in monolayer cultures. Chondrogenic differentiation was subsequently assessed via micromass culture. Having determined that oxygen tension influences murine chondrocyte expansion and differentiation, similar studies were conducted using adult human chondrocytes taken from knee arthroplasty off-cuts, with mRNA expression of select genes involved in the chondrogenic program analyzed by q-PCR.

Results: Cellular morphology was improved in hypoxic culture, with a markedly more fibroblastic appearance seen after greater than 2 passages in 21% O2. Micromass cultures maintained in hypoxic conditions demonstrated stronger staining with Alcian blue, indicating stronger expression of cartilaginous glycosaminoglycans. Collagen type II mRNA expression was two-fold higher in cells expanded at 5% as compared to expansion at 21% O2. Micromass cultures grown at 21% O2 showed up to a twofold increase in the tissue content of glycosaminoglycans when formed with cells expanded at 5% instead of 21% O2. However, no differences in the mRNA expression or staining for collagen type II protein were observed in these micromass cultures. Hypoxia (5% O2) applied during micromass cultures gave rise to tissues with low contents of glycosaminoglycans.

Conclusion: In-vivo, chondrocytes are adapted to a hypoxic environment. Taking this into account, applying 5% O2 in the expansion phase in the course of cell-based cartilage repair strategies, may result in a repair tissue with higher quality by increasing the content of glycosaminoglycans.

Purpose: Core needle biopsy is increasingly accepted for the diagnosis of bone and soft-tissue tumours. Advantages over open biopsy include reduced morbidity, time and cost; however diagnostic accuracy remains a concern. Our objective was to assess and compare the diagnostic accuracy of core needle, open, and fine needle biopsies.

Method: We reviewed 286 cases collected in a prospective database between 2004 and 2007. Of these, 229 had core needle, 32 open, and 25 fine needle biopsies. 230 had soft-tissue lesions, 56 had bone lesions. The results of these biopsies were compared to the final resection diagnosis for accuracy and, where inaccurate, any effects on management.

Results: Ninety-two percent of the core needle, 100% of the open and 72% of the fine needle biopsies had adequate tissue to make a diagnosis. Of the adequate specimens, the accuracy of core/open/fine needle biopsy was 96%, 97% and 94% for determining malignant versus benign; of the correctly identified malignant lesions 97%, 100% and 80% were accurate for histological grade; and 79%, 84%, 59% for histological subtype.

Conclusion: Core needle biopsy yields diagnostic results comparable to open biopsy for determining malignancy and grade in bone and soft-tissue tumours. Fine needle biopsy has a high inadequate sampling rate and should not be used for diagnosing bone and soft-tissue tumours. Given the reduced cost and morbidity associated with core needle biopsies we believe they should be used routinely for diagnosis where possible, and open biopsy reserved for situations where an inadequate specimen is obtained or core biopsy is not feasible.

Purpose: Resection of pelvic sarcoma with limb preservation (internal hemipelvectomy) is a major undertaking. Resection requires large areas of soft-tissue to be removed. Because of wound complications, we manage these defects with immediate tissue transfer (ITT) at the time of resection when a large defect is anticipated. This study compares the outcomes of ITT with primary wound closure (PWC).

Method: Twenty patients undergoing 22 separate procedures (1995–2007) were identified in our prospectively maintained database. Demographics, tumour type, operative data and complications, and functional scores (MSTS-1993, TESS) were collected.

Results: Twelve defects were managed with ITT, nine with pedicled myocutaneous vertical rectus abdominis (VRAM) flaps (one received double VRAM flaps due to the large defect), two with tensor fascia lata (TFL) rotation flaps (one augmented by local V-Y advancement, the other with gluteus maximus rotation flap) and one received latissimus dorsi free tissue transfer. Four wound complications necessitated operative intervention in this group: two debrided VRAM flaps went on to heal and the two TFL flaps required revision: one to VRAM flap and the other to a latissimus dorsi free flap which ultimately suffered chronic infection and hindquarter amputation was performed. Ten defects were managed with PWC, and 5 wound complications occurred, all five suffered infection, one developed hematoma and one dehisced. One wound resolved with debridement, two healed after revision to pedicled gracilis and gluteus maximus myocutaneous flaps. Two patients were converted to hindquarter amputation due to chronic infection. Functional scores were collected on 8 of 12 living patients, at time of writing. The mean TESS scores were 83 and 73 in the ITT and PWC groups. Five patients in the ITT and 3 in the PWC group were deceased.

Conclusion: Soft-tissue closure following pelvic sarcoma resection remains a difficult challenge, and our experience reflects that. There were fewer wound complications (33% v 50%) and slightly better function with ITT than PWC, but this was not statistically significant due to the small size of our study. Although small, this study suggests ITT should be considered whenever a large soft tissue defect is anticipated.

Purpose: The purpose of this study was to prospectively evaluate a consecutive series of patients receiving metal on metal hip resurfacing arthroplasty with regards to outcomes and complications at minimum of 2 years follow-up.

Method: A prospective evaluation of all patients receiving hip resurfacing was performed including baseline evaluation (demographics, WOMAC, SF12, Oxford Hip Score) and minimum 2 year follow-up assessment (WOMAC, SF12, Oxford Hip Score, UCLA activity score, Patient Satisfaction, Complications). No patients were lost to follow-up.

Results: 143 hips in 127 patients received metal-on-metal hip resurfacing arthroplasty. The mean age was 52 years and the primary diagnosis was osteoarthritis or avascular necrosis, Significant improvements were noticed across all baseline quality of life instruments (p< .05) with final mean WOMAC and Oxford Scores 95 (normalized 0–100). Final post-op satisfaction was mean 95 out of 100. Two patient sustained post-operative femoral neck fractures and required revision. An additional two patients required revision for ongoing hip pain. One patient sustained a sciatic nerve palsty and one additional patient required acetabular component repositioning on the same day as the index procedure. Revision procedures involved conversion of resurfacing femoral component to cementless total hip stem with large diameter metal head and preservation of acetabular component. Acetabular component survivorship is 99% and femoral component survivorship is 97% at 2 year follow-up.

Conclusion: Our short to midterm data, from an independant center, suggests excellent improvement in quality of life with high levels of patient satisfaction and postop acitivity level. Our comprehensive post-operative quality of life assessment demonstrates restoration of the hip to rival that of the normal non-arthritic hip joint. Complications unique to resurfacing arthroplasty occur and were not predictable based on pre-operative or intra-operative patient-specific features.

Purpose: Porous tantalum has been shown to be very effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity is insufficient to allow adequate bone ingrowth. We hypothesized that the addition of alendronate to porous tantalum would enhance the ability of porous tantalum to achieve bone ingrowth in these challenging situations, such as when a gap exists between the implant and bone. We evaluated the effect of alendronate coated porous tantalum on new bone formation in an animal model incorporating a gap between implant and bone.

Method: Thirty-six cylindrical porous tantalum implants were bilaterally implanted into the distal femur of 18 rabbits for 4 weeks. There were 3 groups of implants inserted; a control group of porous tantalum with no coatings, porous tantalum with micro-porous calcium phosphate coating, and porous tantalum coated with micro-porous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed by backscattered electron microscopy and fluorescent microscopy on undecalcified samples.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 143% (p< 0.001), 259% (p< 0.001) and 193% (p< 0.001) respectively in the alendronate coated porous tantalum compared with the uncoated porous tantalum controls. The relative increase in the percentage of new bone-implant contact length was increased by 804% on average in the alendronate coated porous tantalum compared with the uncoated tantalum controls.

Conclusion: This study demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss (at the hip, knee or elsewhere), the addition of an alendronate-delivery surface coating would enhance biological fixation of the implant and promote the healing of bone defects.

Introduction: Achieving durable implant–host bone fixation is the major challenge in uncemented revision hip arthroplasty when significant bone stock deficiencies are encountered. The purpose of this study was 1) to develop an experimental model which would simulate the clinical revision hip scenario and 2) determine the effects of alendronate coating on porous tantalum on gap filling and bone ingrowth in the experimental model.

Methods: Thirty-six porous tantalum plugs were implanted into the distal femur, bilaterally of 18 rabbits for four weeks. There were 3 groups of plugs inserted; control groups of porous tantalum plugs (Ta) with no coating, a 2^nd control group of porous tantalum plugs with micro-porous calcium phosphate coating, (Ta-CaP) and porous tantalum plugs coated with alendronate (Ta-CaP-ALN). Subcutaneous fluorochrome labelling was used to track new bone formation. Bone formation was analysed by backscattered electron microscopy and fluorescence microscopy on undecalcified histological sections.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 124 %, 232 % and 170 % respectively in Ta-CaP-ALN compared with the uncoated porous tantalum (Ta) controls, which was statistically significant. The contact length of new bone formation on porous tantalum implants in Ta-CaP-ALN was increased by 700% (8-fold) on average compared with the uncoated porous tantalum (Ta) controls.

Discussion: Alendronate coated porous tantalum significantly modulated implant bioactivity compared with controls. This study has demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth, which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss, the addition of alendronate as a surface coating would enhance biological fixation of the implant and promote the healing of bone defects.

Introduction: Deep infection in total hip replacement can be devastating. We report the outcomes 10–15 years after two stage revision for hip infection in 103 patients using the PROSTALAC (prosthesis of antibiotic-loaded acrylic cement) hip.

Methods: All patients or their next of kin were contacted to determine their current functional status and whether they had required repeat surgery or had recurrent infection. The Oxford-12, SF-12, and WOMAC questionnaires were administered. A comprehensive chart review was undertaken to review the infective organisms, surgery, approach, complications, and need for further revision surgery.

Results: 11 patients had re-infection, 7 of whom responded to repeat surgery with no further sequelae. Two patients required resection arthroplasty, one patient underwent hip disarticulation after eventual failure of treatment and bone loss, and one immuno-compromised patient developed osteomyelitis and was subsequently lost to follow-up. Long-term success rate for two stage-revision is thus 89%, or 96% with additional surgery. Since then, 3 patients required revisions for aseptic loosening, 1 for recurrent dislocation. We were able to follow up 45 patients, 75 % of whom provided health-related quality of life outcome scores. 39 patients were deceased, with their outcome confirmed via their last follow-up or with family members, for a total follow-up rate of 85 %. 15 patients were lost to follow-up, but did not undergo further surgery or have reinfections treated at our centre.

Discussion: Two-stage revision for hip infection, which includes an interim prosthesis of antibiotic loaded cement, offers a predictable and lasting solution for patients with this difficult problem.

Introduction: The aims of this study were to

determine predictors of pain, function and activity level 1–2 years after revision hip arthroplasty and

Methods: A prospective cohort of 222 patients who underwent revision hip arthroplasty were evaluated. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at 1 and 2 years post surgery. The dependent outcome variables were WOMAC function, pain and UCLA activity. The independent variables included patient demographic, surgery specific and objective parameters including baseline Western Ontario McMaster Universities (WOMAC) osteoarthritis index, and the Short Form-12 mental component. The Loess method was used to plot the change of WOMAC and SF-12 scores over time.

Results: There was a significant improvement (p< 0.001) in all patient quality of life scores from baseline with results plateauing at 1 year. UCLA activity remained static between 1 and 2 years. In the predictive model, higher baseline WOMAC function (p < 0.001), age between 60–70 (p< 0.037), male gender (0.017), lower Charnley class (p < 0.001) and diagnosis of aseptic loosening (p < 0.003) were significant predictors of improved function.

When considering WOMAC pain as an outcome variable, factors predictive of improving category outcome included baseline WOMAC function (p= 0.001), age between 60–70 (p< 0.004), male gender (p= 0.005), lower Charnley class (p< 0.001) and no previous revisions (p < 0.023). Baseline WOMAC pain did not predict final pain outcome. Baseline WOMAC function (p=0.001), the indication for the operation (p=0.007), and the operating surgeon were significant predictors of UCLA activity at follow up. Peri or post-operative complications were not an adverse predictor of physical function, pain or activity.

Conclusions: Predictors of quality of life outcomes after revision hip replacement-showed that although some patient specific and surgical specific variables were important, age, gender, Charnley class and baseline WOMAC function had the most robust associations with outcomes.

Revision of a failed acetabular reconstruction in total hip arthroplasty (THA) can be challenging when associated with significant bone loss. In cementless revision THA, achieving initial implant stability and maximising host bone contact is key to the success of reconstruction. Porous tantalum acetabular shells may represent an improvement from conventional porous coated uncemented cups in revision acetabular reconstruction associated with severe acetabular bone defects.

Methods: We reviewed the clinical and radiographic results of 46 acetabular revisions with Paprosky 2 and 3 acetabular bone defects done with a hemispheric, tantalum acetabular shell (Trabecular Metal Revision Shell, Zimmer, Warsaw, USA) and multiple supplementary screws for fixation.

Results: At a mean follow-up of 40 (24–51) months, one acetabular shell had been revised in a patient with a Paprosky 3B defect. Two liner revisions were performed for recurrent instability, without porous tantalum shell revision. The clinical outcome showed significant postoperative improvement in all measured sub-scales, compared with baseline pre-operative scores (mean improvement in Oxford Hip Score of 40.0, p < 0.001, in WOMAC of 36.7, p < 0.001, Physical component SF-12 of 12.3, p =0.0003, mental component of SF-12 of 6.8, p = 0.006). Radiographic evidence of osseointegration using validated criteria (Moore’s criteria) was demonstrated in 39 of the 40 hips available for radiographic analysis at a mean of 30.9 months, by two independent observers. Of the remaining six hips, five hips were lost to follow-up and one radiograph demonstrated failure of the hip reconstruction secondary to loss of fixation and superior migration of the component.

Discussion: Cementless acetabular revision with the porous tantalum acetabular shell demonstrated excellent early clinical and radiographic results in a series of complex revision acetabular reconstruction associated with severe bone defects. The evidence of radiographic osseointegration suggests that outcome should remain favourable, however, further longer-term evaluation is warranted.

Introduction: This single incision, anterolateral intermuscular approach (AL-IM) utilizes the interval between gluteus medius and tensor fascia lata. The aims of the study were to compare the quality of life, satisfaction and complications of this approach with two of the most commonly used limited incision transmuscular (TM) approaches, namely the mini-posterior (P-TM) and the mini-direct lateral (L-TM).

Methods: 199 patients receiving MIS THA surgical procedures were evaluated prospectively (63 AL-IM, 68 P-TM and 68 L-TM). The outcome variables were WOMAC function, pain, stiffness, SF-12 (physical & mental), Oxford-12, satisfaction and radiological outcome. Parametric and non-parametric analyses were performed.

Results: There were no significant differences between groups in baseline characteristics including age, sex, BMI, co-morbidity, or pre-op WOMAC, SF-12, Oxford-12 (p> .05). However, the AL-IM group was associated with superior outcomes (p< .05) in WOMAC function, WOMAC pain, global WOMAC, Oxford-12 and SF-12 physical component.

Conclusion: In the short term the AL-IM approach provides significant improvements in quality of life scores over other limited incision approaches. It provides minimal soft tissue disruption and maintains the abductor musculature and posterior soft tissue envelope, with similar complications and radiological outcomes.