Prior Femoral Canal Instrumentation is a Major Risk Factor for Fixation Failure after Distal Femoral Replacement.
Academic Article
Overview
abstract
INTRODUCTION: Distal femoral replacement (DFR) is a salvage option for massive femoral bone loss and is often performed in revision total knee arthroplasty (rTKA) that have undergone multiple prior procedures. This study aimed to report on a large cohort of DFRs performed at a tertiary referral institution regarding survivorship and risk factors for aseptic loosening, specifically the impact of a previously instrumented femoral canal. METHODS: Between 2016 and 2021, 105 patients undergoing rTKA to DFR with a minimum two-year follow-up were identified. Kaplan-Meier estimates assessed survivorship free from all-cause reoperation, all-cause revision, and revision for aseptic loosening. Logistic regression was conducted to assess potential risk factors for radiographic loosening and the need for revision. RESULTS: Prior femoral canal instrumentation was identified in 59% of cases, and 54% had undergone multiple prior procedures. The two-year survivorship free from revision for aseptic loosening was 93%. The two-year survivorship free from all-cause reoperation was 87% for native canals and 59% for previously instrumented canals (P = 0.008). The two-year survivorship free from all-cause revision was 100 and 81%, respectively (P = 0.014). Regression analysis found re-rTKA (Odds Ratio [OR] = 18.3, P = 0.006), prior femoral canal instrumentation (OR = 14.6, P = 0.01), and prior femoral canal cementation (OR = 8.2, P = 0.007) to be risk factors for aseptic loosening. CONCLUSIONS: A DFR for rTKA had high two-year survivorship free from revision for aseptic loosening (93%). Regression analysis revealed multiple risk factors for aseptic femoral component loosening with a previously instrumented femoral canal, resulting in a 2.8-times higher rate of reoperation, a 10.5-times higher rate of all-cause revision, and an 11-times higher rate of aseptic loosening. Future research on fixation strategies in sclerotic, previously instrumented femoral canals should be prioritized to reduce the risk of fixation failure in this high-risk cohort.
