Beauchamp, C.P.

AbstractBackgroundInnovations in machined and three‐dimensionally (3D) printed implant technology have allowed for customized complex pelvic reconstructions. We sought to determine the survivorship of custom hemipelvis reconstruction using ilium‐only fixation at a minimum 2‐year follow‐up, their modes of failure, and the postoperative complications resulting from the procedure.MethodsA retrospective review identified 12 consecutive patients treated with custom hemipelvis reconstruction. Indications for surgery were bone tumor requiring internal hemipelvectomy (four patients) or multiply revised, failed hip arthroplasty with massive bone loss (eight patients). All patients had a minimum of 2‐year follow‐up with a mean of 60.5 months. Kaplan–Meier survivorship analysis was determined for all patients. Postoperative complications and reoperations were categorized for all patients.ResultsAt a mean of 60.5 months, 11 of 12 patients had retained their custom implant (92% survivorship). One implant was removed as a result of an acute periprosthetic joint infection (PJI). There were no cases of aseptic loosening. Seven of 12 patients required reoperation (three PJI; two dislocations; two superficial wound complications), with five patients going on to reoperation‐free survival.ConclusionsCustom hemipelvis reconstruction utilizing an ilium monoflange provides durable short‐term fixation at a minimum 2‐year follow‐up. Reoperation for infection and dislocation is common.

Aims The aim of this study was to determine the diagnostic accuracy of α defensin (AD) lateral flow assay (LFA) and enzyme-linked immunosorbent assay (ELISA) tests for periprosthetic joint infection (PJI) in comparison to conventional synovial white blood cell (WBC) count and polymorphonuclear neutrophil percentage (PMN%) analysis. Methods Patients undergoing joint aspiration for evaluation of pain after total knee arthroplasty (TKA) or total hip arthroplasty (THA) were considered for inclusion. Synovial fluids from 99 patients (25 THA and 74 TKA) were analyzed by WBC count and PMN% analysis, AD LFA, and AD ELISA. WBC and PMN% cutoffs of ≥ 1,700 cells/mm3 and ≥ 65% for TKA and ≥ 3,000 cells/mm3 and ≥ 80% for THA were used, respectively. A panel of three physicians, all with expertise in orthopaedic infections and who were blinded to the results of AD tests, independently reviewed patient data to diagnose subjects as with or without PJI. Consensus PJI classification was used as the reference standard to evaluate test performances. Results were compared using McNemar’s test and area under the receiver operating characteristic curve (AUC) analysis. Results Expert consensus classified 18 arthroplasies as having failed due to PJI and 81 due to aseptic failure. Using these classifications, the calculated sensitivity and specificity of AD LFA was 83.3% (95% confidence interval (CI) 58.6 to 96.4) and 93.8% (95% CI 86.2 to 98.0), respectively. Sensitivity and specificity of AD ELISA was 83.3% (95% CI 58.6 to 96.4) and 96.3% (95% CI 89.6 to 99.2), respectively. There was no statistically significant difference between sensitivity (p = 1.000) or specificity (p = 0.157) of the two AD assays. AUC for AD LFA was 0.891. In comparison, AUC for synovial WBC count, PMN%, and the combination of the two values was 0.821 (sensitivity p = 1.000, specificity p < 0.001), 0.886 (sensitivity p = 0.317, specificity p = 0.011), and 0.926 (sensitivity p = 0.317, specificity p = 0.317), respectively. Conclusion The diagnostic accuracy of synovial AD for PJI diagnosis is comparable and not statistically superior to that of synovial WBC count plus PMN% combined. Cite this article: Bone Joint J 2021;103-B(6):1119–1126.

The PROSTALAC functional spacer is made of antibiotic-loaded acrylic cement but has a small metal-on-polythene articular surface. We have used it as an interim spacer in two-stage exchange arthroplasty for infected total knee replacement. PROSTALAC allows continuous rehabilitation between stages as it maintains good alignment and stability of the knee and a reasonable range of movement. It also helps to maintain the soft-tissue planes, which facilitates the second-stage procedure. We reviewed 45 consecutive patients, treated over a period of nine years. The mean follow-up was for 48 months (20 to 112). At final review, there was no evidence of infection in 41 patients (91%); only one had a recurrent infection with the same organism. There was improvement in the Hospital for Special Surgery knee score between stages and at final review. The range of movement was maintained between stages. Complications were primarily related to the extensor mechanism and stability of the knee between stages. Both of these problems decreased with refinement of the design of the implant. The rate of cure of the infection in our patients was similar to that using other methods. Movement of the knee does not appear to hinder control of infection.

We describe a U-shaped approach to the distal femur which, having divided the extensor mechanism and elevated the entire quadriceps muscle, gives excellent exposure and allows a number of reconstructive options. It was used in 14 patients, 13 of whom were followed up for a mean of 3.5 years (1 to 11). There was no case of flap necrosis, and complications related to the reconstruction were acceptable.