Distal femoral replacement carries higher infection and revision risk than ORIF for distal femoral periprosthetic fractures in elderly patients.

Abstract

Distal femoral periprosthetic fractures following TKA are increasingly common in elderly patients. Surgical management most commonly involves either open reduction and internal fixation (ORIF) or distal femoral replacement (DFR); however, comparative data regarding short-term and long-term complications remain limited. As such, this study compared complications between ORIF and DFR in elderly patients with distal femoral periprosthetic fractures following TKA. A retrospective cohort study was performed using the TriNetX Research Network. Patients aged ≥65 years with distal femoral periprosthetic fractures were identified and categorized by operative treatment. Propensity score matching was performed to balance cohorts. Short-term complications were assessed at 90 days, and long-term complications were evaluated at 1 and 5 years. Complications were compared using risk differences and risk ratios with 95% confidence intervals, and Kaplan-Meier survival methods. After matching, 698 patients remained in each cohort. Most 90-day complications were similar between groups. However, DFR was associated with higher rates of wound disruption (7.6% vs 2.7%, RR 2.79 [95% CI 1.67-4.66], p<0.001) and transfusion (17.5% vs 13.0%, RR 1.34 [1.04-1.72], p=0.021). At 5-year follow-up, DFR demonstrated higher risks of periprosthetic joint infection (22.5% vs 5.3%, RR 4.24 [3.01-5.98], p<0.001), revision TKA (15.5% vs 3.3%, RR 4.70 [3.03-7.27], p<0.001), and subsequent knee procedures (24.4% vs 14.9%, RR 1.64 [1.31-2.04], p<0.001). Conversely, repeat periprosthetic fractures were more frequent following ORIF (55.3% vs 44.8%), with DFR demonstrating a lower relative risk (RR 0.81 [0.73-0.90], p<0.001). Similarly, additional fixation procedures occurred more often after ORIF (4.9% vs 1.6%), while DFR was associated with a reduced relative risk (RR 0.32 [0.17-0.63], p<0.001). Mortality was similar between approaches at both 30 days (2.2% vs 2.2%, RR 1.00 [0.48-2.08], p=1.00) and 5 years (16.0% vs 15.4%, RR 1.04 [0.81-1.33], p=0.764). Short-term systemic complication rates were comparable between approaches, although DFR was associated with greater perioperative morbidity. Over longer follow-up, DFR demonstrated higher implant-related infection and revision risks, whereas ORIF carried higher risks of refracture and secondary fixation. These findings highlight a tradeoff between the immediate stability and mobilization of DFR and longer-term implant-related complications, supporting individualized treatment selection based on patient-specific risk factors.