Outcomes Following Distal Femur Replacement for Fracture: A Multi-Institutional Retrospective Review

OBJECTIVES: To estimate representative outcomes of patients who underwent distal femur replacement (DFR) for distal femur fractures (DFFs). METHODS: Design : Retrospective Cohort Study Setting: Twelve academic trauma centers in the United States Patient Selection Criteria: Adult patients who underwent DFR for native or periprosthetic DFF (OTA/AO 33A1.1 – 33C3.3) from 2010 to 2022 were included. Patients who underwent DFR for infectious, oncologic, and/or other indications besides fracture fixation were excluded. Outcome Measures and Comparisons: The primary outcome was periprosthetic joint infection (PJI). Secondary outcomes included reoperation, one-year mortality, and function. Outcomes were estimated using proportions and Kaplan-Meier curves with 95% confidence intervals (C.I.) and stratified by periprosthetic fracture with Fisher’s exact testing. RESULTS: 173 patients were included, with 130 (75%) having a periprosthetic DFF. The median age was 77 [interquartile range, 70-84] and median final follow-up was 6 months [interquartile range, 2-14], with 146 (84%) females and several medical co-morbidities (63% ASA class III and 24% ASA class IV). The rate of PJI was 5.8% (95% C.I., 3.1-10.5%). PJI was 2.3% for native compared to 6.9% for periprosthetic DFF (P = 0.45). The reoperation rate was 16.6% (95% C.I., 11.7-23.0%), and one-year mortality was 27% (95% C.I., 20-35%). Fifty-five percent of patients returned to their baseline function (95% C.I., 46.9-62.1%). CONCLUSIONS: DFR for native and periprosthetic DFF was associated with a PJI rate of 5.8%. The one-year mortality rate was 27.0%, and reoperation rate was 16.6%. Fifty-five percent of patients returned to their baseline function. DFR can be considered as an option in cases of complex native and periprosthetic DFF, though surgeons should continue to counsel patients on the considerable risks associated with DFR when assessing treatment options. LEVEL OF EVIDENCE: Therapeutic Level III.