Two-stage revision for prosthetic joint infection: predictors of outcome and the role of reimplantation microbiology

We describe rates of success for two-stage revision of prosthetic joint infection (PJI), including data on reimplantation microbiology. Methods: We retrospectively collected data from all the cases of PJI that were managed with two-stage revision over a 4 year period. Patients were managed with an antibiotic-free period before reimplantation, in order to confirm, clinically and microbiologically, that infection was successfully treated. Results: One hundred and fifty-two cases were identified. The overall success rate (i.e. retention of the prosthesis over 5.75 years of follow-up) was 83%, but was 89 % for first revisions and 73 % for re-revisions [hazard ratio2.9, 95 % confidence interval (CI) 1.2–7.4, P0.023]. Reimplantation microbiology was frequently positive (14%), but did not predict outcome (hazard ratio1.3, 95 % CI 0.4–3.7, P0.6). Furthermore, most unplanned debridements following the first stage were carried out before antibiotics were stopped (25 versus 2 debridements). Conclusions: We did not identify evidence supporting the use of an antibiotic-free period before reimplantation and routine reimplantation microbiology. Re-revision was associated with a significantly worse outcome

Pelvic position and movement during hip replacement

The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior > lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required

Pelvic position and movement during hip replacement

The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required

One hundred and twelve infected arthroplasties treated with ‘DAIR’ (debridement, antibiotics and implant retention): antibiotic duration and outcome

OBJECTIVES: We describe treatment failure rates by antibiotic duration for prosthetic joint infection (PJI) managed with debridement, antibiotics and implant retention (DAIR). METHODS: We retrospectively collected data from all the cases of PJI that were managed with DAIR over a 5 year period. Surgical debridement, microbiological sampling, early intravenous antibiotics and prolonged oral follow-on antibiotics were used. RESULTS: One hundred and twelve cases of PJI were identified. Twenty infections (18%) recurred during a mean follow-up of 2.3 years. The mean duration of antibiotic use was 1.5 years. Failure was more common after arthroscopic debridement, for previously revised joints and for Staphylococcus aureus infection. There were 12 failures after stopping antibiotics and 8 while on antibiotics [hazard ratio (HR) = 4.3, 95% confidence interval (CI) 1.4-12.8, P = 0.01]. However, during the first 3 months of follow-up, there were eight failures after stopping antibiotics and two while on antibiotics (HR = 7.0, 95% CI 1.5-33, P = 0.015). The duration of antibiotic therapy prior to stopping did not predict outcome. CONCLUSIONS: PJI may be managed by DAIR. The risk of failure with this strategy rises after stopping oral antibiotics, but lengthening antibiotic therapy may simply postpone, rather than prevent, failure

Indications and results of unicompartmental arthroplasty

There is currently a resurgence of interest in unicompartmental knee replacement (UKR), primarily because of the minimally invasive approach but also because there are now some reports of UKR achieving similar long-term survival rates to total knee replacement (TKR). These improved survival rates are the result of more precise indications, improved implant design, and better surgical techniques. To achieve good 10-year survival with fixed bearing devices, precise indications are necessary; approximately 1 in 10 patients requiring knee replacement are appropriate. The indications are not as narrow when using a mobile bearing device such as the Oxford knee, because of improved wear resistance and instrumentation; approximately one in four patients are appropriate. However, the mobile bearing device is technically more demanding to implant than most fixed bearing devices. There is a vogue to consider UKR to be a preknee replacement. As a result, many new prosthetic designs are being implanted with a minimally invasive approach often with poor instrumentation in a very wide range of patients. It is our belief that those patients who satisfy the accepted indications should be treated with a proven design using sophisticated instrumentation. It remains debatable whether those patients who do not satisfy these indications should have a UKR as a preknee replacement or should have a TKR. © 2003 Lippincott Williams and Wilkins, Inc

Proximal femoral reconstruction for revision hip arthroplasty with severe bone loss: A new technique using autologous bone graft and a proximally loading femoral component

We report the results of a new method of reconstructing the femur in 22 patients with severe bone loss having revision hip arthroplasty. The calcar and metaphysis were reconstructed with cortico-cancellous autograft around a new modular hip replacement. The metaphyseal portion of the implant is free to slide on the stem and therefore loads the graft and, we believe, encourages bone graft incorporation. The stem gains cementless fixation distal to the area of bone loss, thus preventing fractures and allowing the areas of bone loss to heal. At the time of review at a mean of 8 years follow-up there had been no revisions (since then there has been one re-revision due to recurrence of infection). The modified D'Aubigne and Postel hip score improved from 7.3 to 15. In 17 patients the graft has incorporated, in 5 it has partially resorbed but the prosthesis remains secure. We conclude that this is a relatively simple and successful technique for overcoming the problem of major femoral bone loss