THE EPIDEMIOLOGY AND OUTCOMES OF PERIPROSTHETIC FEMUR FRACTURES: THE SCOTTISH NATIONAL AUDIT OF PERIPROSTHETIC FEMUR FRACTURES (SNAP FEMUR) STUDY

Periprosthetic femoral fractures (PFFs) are underreported in national registries, making their impact on healthcare services difficult to quantify. This study aimed to describe PFF patient characteristics, management, and outcomes, and to compare these with native hip fractures (NHFs) using Scottish Hip Fracture Audit (SHFA) data. This was a nationwide retrospective cohort study of patients aged ≥50 who sustained a PFF and were treated in 16 centres over 12 months (2019). Data included demographics, Clinical Frailty Scale (CFS) score, treatment modality, and mortality. Comparisons with NHF were made, and Cox regression was used to identify mortality predictors, adjusting for confounders. A total of 328 PFFs were included (mean age 79, SD 10; 66% female). Median follow-up was 2.8 years (IQR 1.67–3.22). Compared to NHF patients, those with PFF were less frail (median CFS 4 vs 5, p<0.001) and more often home-dwelling (91% vs 76%, p<0.001). Most PFFs occurred around arthroplasties (93.5%), involving the hip (70%) or knee (24%). Management included fixation (53%), revision arthroplasty (30%), and conservative care (15%). Median hospital stay was 15 days (IQR 8–28), and one-year mortality was 21%. Independent mortality predictors included interprosthetic fracture (aHR 2.65, p=0.003), male sex (aHR 1.76, p=0.015), older age (per year: aHR 1.07, p<0.001), and higher frailty (CFS 5–9: aHR 4.16, p=0.027). PFF patients were less frail than NHF patients but had prolonged hospital stays and high one-year mortality. As 70% of PFFs did not undergo revision arthroplasty, registry-based surveillance underestimates their true burden.