Predictors of short-term outcomes after postoperative periprosthetic femoral fracture : a UK linked data analysis.

Aims: Postoperative periprosthetic femoral fractures (POPFFs) following hip and knee arthroplasty are increasing. They often have poor outcomes. We have limited understanding of the predictors of these outcomes, which this study addresses. Methods: We extracted administrative hospital data for patients aged 18 years and above with admissions to NHS hospitals in England with a primary diagnosis of POPFF between April 2016 and December 2022, including demographic characteristics, comorbidities, surgery for POPFF, admission source, outpatient department (OPD) appointments, and pre-POPFF admissions. Data were linked to the national death register. The most relevant available hospital-level key performance indicators (KPIs) were taken from the National Hip Fracture Database (NHFD). We used multilevel models with random intercepts for hospitals to predict in-hospital death, 30-day death, length of stay (LOS) above the upper quartile, and 30-day emergency readmission. Results: A total of 33,728 patients were included, with a median age of 82 years (IQR 73 to 88); 65.9% were female. In total, 1,510 deaths occurred within 30 days of admission. In multiple regression models, age was associated with higher mortality and longer LOS. Females showed lower odds of mortality and 30-day readmission. Congestive heart failure and liver disease were more strongly linked to all adverse outcomes than were other comorbidities. Fixation (odds ratio (OR) 0.72, 95% CI 0.64 to 0.81) and revision (OR 0.78, 95% CI 0.68 to 0.91) were associated with lower 30-day mortality but longer hospital stays than having neither procedure. Previous hip fracture was associated with 30-day readmission and longer LOS but not with mortality. Admission from a care home was associated with higher 30-day mortality (OR 1.70, 95% CI 1.31 to 2.39), but shorter LOS. Previous any-cause emergency admissions and missed outpatient appointments were associated with worse outcomes. Hospital-level NHFD KPIs for POPFF and admission numbers for POPFF were not associated with any outcome. Conclusion: We identified several patient factors, but no hospital factors, associated with adverse short-term outcomes following POPFF admission.