Abstract
PurposeMegaprosthetic distal femoral reconstruction (DFR) is a limb-salvage procedure to address bone loss following two-stage revision for periprosthetic knee joint infection (PJI). The purpose of this study was to analyze the survival of DFR compared to hinged total knee arthroplasty (TKA). It was hypothesized that DFR was associated with a poorer survival.MethodsIn this retrospective single-center study, 97 subjects who underwent two-stage revision of chronic knee PJI were included. Among these, 41 were DFR. The diagnosis of PJI was established using the Musculoskeletal Infection Society (MSIS) criteria. Implant survival was calculated using Kaplan–Meier method and compared with the log-rank test as well as multivariate Cox regression at a minimum follow-up period of 24 months.ResultsThe median follow-up period was 59 (interquartile range (IQR) 45–78) months. Overall, 24% (23/97) of patients required revision surgery for infection. The infection-free survival of rotating hinge revision TKA was 93% (95% Confidence Interval (CI) 86–100%) at five years compared to 50% (95% CI 34–66%) for DFR. In multivariate analysis, the risk factors for reinfection were DFR reconstruction (HR 4.7 (95% CI 1–22), p = 0.048), length of megaprosthesis (HR 1.006 (95% CI 1.001–1.012), p = 0.032) and higher BMI (HR 1.066, 95% CI 1.018–1.116), p = 0.007). 10% (4/41) of patients undergoing DFR underwent amputation to treat recurrent infection.ConclusionMegaprosthetic DFR as part of a two-stage exchange for PJI is a salvage treatment that has a high risk for reinfection compared to non-megaprosthetic TKA. Patients must therefore be counseled accordingly.Level of evidenceRetrospective observational study, Level IV.
Highlights
Periprosthetic joint infection is one of the most devastating complications following total knee arthroplasty (TKA) and the prevalence is estimated to be about 1–2% for primary joint replacements [17]
The survival of non-megaprosthetic revision TKA was 96% and 93% at two and five years, respectively
Distal femoral replacement (DFR) was found to be at increased risk for reinfection compared to non-megaprosthetic reconstruction (HR 4.7, p = 0.048) as well as larger implants (HR 1.006, p = 0.032) and a higher body mass index (BMI) (HR 1.066, 95% Confidence interval (CI) 1.018–1.116), p = 0.007)
Summary
Periprosthetic joint infection is one of the most devastating complications following total knee arthroplasty (TKA) and the prevalence is estimated to be about 1–2% for primary joint replacements [17]. One of the most challenging problems following debridement of infected tissue is bone loss and can result in a large metaphyseal bone defect with loss of the femoral condyles that can even extent to the diaphysis [9, 14]. For such defects, modular megaprosthetic reconstruction, of the distal femur can be considered [2, 14, 25] based on the long-term experience from tumor surgery [12, 13, 24]. Only little is known about complications of such megaprostheses when used for knee PJI [26]
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