Tapered, fluted, modular, titanium stems are increasingly popular in the operative management of Vancouver B2 and selected B3 peri-prosthetic femoral fractures. We have reviewed the results at our institution looking at stem survival and clinical outcomes and compared this with reported outcomes in the literature. Stem survival at a mean of 54 months was 96% in our series and 97% for combined published cases. Review of radiology showed maintenance or improvement of bone stock in 89% of cases with high rates of femoral union. Favourable clinical outcome scores have reported by several authors. No difference in survival or clinical scores was observed between B2 and B3 fractures. Tapered stems are a useful option in revision for femoral fracture across the spectrum of femoral bone deficiency.

Cite this article: Bone Joint J 2013;95-B, Supple A:17–20.

Tapered, fluted, modular, titanium stems have a long history in Europe and are increasing in popularity in North America. We have reviewed the results at our institution looking at stem survival and clinical outcomes. Radiological outcomes and quality of life assessments have been performed and compared to cylindrical non-modular cobalt chromium stems. Survival at five years was 94%. This fell to 85% at ten years due to stem breakage with older designs. Review of radiology showed maintenance or improvement of bone stock in 87% of cases. Outcome scores were superior in tapered stems despite worse pre-operative femoral deficiency. Tapered stems have proved to be a useful alternative in revision total hip arthroplasty across the spectrum of femoral bone deficiency.

Antibiotic impregnated articulating spacers are used in two-stage revision total knee arthroplasty to deliver local antibiotic therapy while preserving function. We have observed infection control in greater than 95% of cases with functional outcomes approaching those seen in revision for aseptic loosening. Higher failure has been observed with methicillin resistant organisms.

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

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: 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: 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.

We report the outcome at ten to 15 years of two-stage revision for hip infection in 99 patients using the Prostalac articulated hip spacer system.

All the patients were contacted to determine their current functional and infection status using the Oxford-12, Short form-12, and Western Ontario and McMaster University Osteoarthritis Index questionnaires. A total of 11 of the 99 patients had a further infection, of whom seven responded to repeat surgery with no further sequelae. The mean interval between the stages was five months (1 to 36). We were able to review 48 living patients, with a mean age of 72 years (46 to 86), 34 (71%) of whom provided health-related quality-of-life outcome scores.

The mean follow-up was 12 years (10 to 15). The long-term success rate was 89% and with additional surgery this rose to 96%. The mean global Western Ontario and McMaster University Osteoarthritis Index score was 80.6 (sd 18.3). The mean Oxford-12 score was 74.0 (sd 22.3), and the mean Short form-12 score was 53.1 (sd 9.4) (mental) and 33.5 (sd 13.5) (physical). The mean satisfaction score was 90.5 (sd 15.3).

Two-stage revision for hip infection using a Prostalac interim spacer offers a predictable and lasting solution for patients with this difficult problem.

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.

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: 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.

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.

A prospective cohort of 222 patients who underwent revision hip replacement between April 2001 and March 2004 was evaluated to determine predictors of function, pain and activity level between one and two years post-operatively, and to define quality of life outcomes using validated patient reported outcome tools. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at one and two years post-operatively. The dependent outcome variables were the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function and pain scores, and University of California Los Angeles activity scores. The independent variables included patient demographics, operative factors, and objective quality of life parameters, including pre-operative WOMAC, and the Short Form-12 mental component score.

There was a significant improvement (t-test, p < 0.001) in all patient quality of life scores. In the predictive model, factors predictive of improved function (original regression analyses, p < 0.05) included a higher pre-operative WOMAC function score (p < 0.001), age between 60 and 70 years (p < 0.037), male gender (p = 0.017), lower Charnley class (p < 0.001) and aseptic loosening being the indication for revision (p < 0.003). Using the WOMAC pain score as an outcome variable, factors predictive of improvement included the pre-operative WOMAC function score (p = 0.001), age between 60 and 70 years (p = 0.004), male gender (p = 0.005), lower Charnley class (p = 0.001) and no previous revision procedure (p = 0.023). The pre-operative WOMAC function score (p = 0.001), the indication for the operation (p = 0.007), and the operating surgeon (p = 0.008) were significant predictors of the activity assessment at follow-up.

Predictors of quality of life outcomes after revision hip replacement were established. Although some patient-specific and surgery-specific variables were important, age, gender, Charnley class and pre-operative WOMAC function score had the most robust associations with outcome.

Removal of well-fixed, cementless, acetabular components during revision arthroplasty remains a challenging problem. Further damage to host bone may limit options for reconstruction and compromise the long-term result of the revision operation. We report the results of 31 hips with well-fixed, cementless sockets which were removed using a new cup extraction system. In all hips the socket was removed without difficulty and with minimal further bone loss.

We have undertaken a prospective evaluation of health-related quality-of-life outcomes in 26 consecutive patients undergoing periacetabular osteotomy with a minimum follow-up of 24 months (24 to 42). The Western Ontario-Macmaster (WOMAC) and Short Form 36 (SF-36) outcome measures were evaluated preoperatively and at follow-up. Secondary outcome measures included retrospective assessment of sports activity and satisfaction with the procedure.

Follow-up data were available for 22 patients (85%). A significant improvement in the pain (p < 0.0001) and function (p < 0.0001) scales of the WOMAC and the SF-36 physical score (p < 0.0001) was seen. The mean sports activity score improved from 1.9 to 4.4, with a very high mean satisfaction rating of 89.7/100.

A significant improvement in both global and disease-specific health outcomes can be expected after this operation, with a high rate of satisfaction and improvement in sporting activities.

There are few medium- and long-term data on the outcome of the use of proximal femoral structural allografts in revision hip arthroplasty. This is a study of a consecutive series of 40 proximal femoral allografts performed for failed total hip replacements using the same technique with a minimum follow-up of five years (mean 8.8 years; range 5 to 11.5 years). In all cases the stem was cemented into both the allograft and the host femur. The proximal femur of the host was resected in 37 cases.

There were four early revisions (10%), two for infection, one for nonunion of the allograft-host junction, and one for allograft resorption noted at the time of revision of a failed acetabular reconstruction. Junctional nonunion was seen in three patients (8%), two of whom were managed successfully by bone grafting, and bone grafting and plating respectively. Instability was observed in four (10%). Trochanteric nonunion was seen in 18 patients (46%) and trochanteric escape in ten of these (27%). The mean Harris hip score improved from 39 to 79. Severe resorption involving the full thickness of the allograft was seen in seven patients (17.5%). This progressed rapidly and silently, but has yet to cause failure of any of the reconstructions.

Profound resorption of the allograft may be related to a combination of factors, including a slow form of immune rejection, stress shielding and resorption due to mechanical disuse with solid cemented distal fixation, and the absence of any masking or protective effect which may be provided by the retention of the bivalved host bone as a vascularised onlay autograft. Although continued surveillance is warranted, the very good medium-term clinical results justify the continued use of structural allografts for failed total hip replacements with severe loss of proximal femoral bone.

We have previously described a simple and reproducible three-dimensional technique of CT for the measurement of the cover of the femoral head in acetabular dysplasia in adults. We now describe the application of this technique in ten patients with symptomatic dysplasia to assess the degree and direction of dysplasia and to measure the cover obtained at acetabular osteotomy.

The indices obtained gave a useful indication of the degree and direction of the dysplasia and confirmed which components had been used most efficiently to achieve cover. The information is easily presented in graphical form and gives a clearer indication of the cover obtained than the indices derived from plain radiographs.