Functional outcomes of periprosthetic and non-periprosthetic distal femur fractures: a comparative study

Abstract

Aim: The purpose of this study was to compare the outcomes of locked plating in closed distal femur periprosthetic, and non-periprosthetic fractures. We hypothesized that the outcomes would be superior in the non-periprosthetic distal femur fracture group. Material and Method: Patients who underwent surgery for distal femur fractures between January 2019 and January 2022 were retrospectively reviewed. Patients aged under 18 years, who had multiple fractures, pathological fractures, follow-up less than 6 months, previous history of revision knee arthroplasty, interprosthetic fractures between hip and knee arthroplasties, fixation performed other than distal locking femoral plate and intra-operative periprosthetic fractures were excluded. Patients’ age, gender, laterality, length of hospital stay, and follow-up duration were obtained from hospital registry notes. Fractures were classified using the AO classification system. At the last follow-up, visual analogue scale (VAS), Tegner activity score, Lysholm knee score, and short form 36 (SF-36) scores were noted. Results: A total of 30 patients met the inclusion criteria and were included in the study. There were 14 patients in the non-periprosthetic fracture group and 16 patients in the periprosthetic fracture group. The periprosthetic group had significantly lower mean VAS score (p=0.047), Tegner activity score (p=0.015), and Lysholm knee score (p=0.034) than the non-periprosthetic group. The periprosthetic fracture group had significantly inferior quality of life scores compared to non-periprosthetic groups based on SF-36 sub-parameters. Conclusion: Periprosthetic distal femoral fractures have inferior clinical outcomes and quality of life than non-periprosthetic fractures despite having similar fracture healing rate. Orthopaedic surgeons should be aware of the frailty of the patients caused by prior total knee arthroplasty surgery.