Risk Factors for Postoperative Stem Revision in Patients with Periprosthetic Femoral Fractures after Primary Total Hip Arthroplasty: Nationwide Outcomes Based on the Dutch Arthroplasty Registry

Purpose: This study aimed to determine the incidence of postoperative primary total hip arthroplasty (THA) stem revision due to periprosthetic fractures (PPF) and analyze related patient and surgical factors. Materials and Methods: Utilizing the Kaplan–Meier analysis and Cox regression method to identify risk factors for stem revision due to PPF, this study analyzed 331,009 primary THA procedures from the Dutch Arthroplasty Register between 2007 and 2021. Results: At 10-year follow-up, the incidence rate was 0.7%. Patient specific factors with significant incidence probabilities were higher age (hazard ratio [HR] 1.29 per 10 years, 95% confidence interval [CI] 1.22-1.36), female sex (HR 1.30, 95% CI 1.16-1.45), American Society of Anesthesiologists (ASA) class II (HR 1.56, 95% CI 1.27-1.93) and ASA class III-IV (HR 2.07, 95% CI 1.59-2.71), Charnley score B2 (HR 1.46, 95% CI 1.23-1.72) and Charnley score C (HR 1.81, 95% CI 1.26-2.59), and higher body mass index (BMI) (HR 1.02 per kg/m², 95% CI 1.00-1.03). Surgery specific factors with significant incidence probabilities were interventions with an uncemented stem (HR 4.55, 95% CI 3.85-5.26), and anterior approach compared to posterolateral approach (HR 1.25, 95% CI 1.03-1.52). Conclusion: The highest risk of PPF in THA requiring stem revision was found in older female patients with high ASA class, Charnley score and BMI as well as uncemented implants. This result may prompt surgeons to strive for cemented stem fixation in patients with declining bone stock when feasible. Furthermore, care should be taken when using anterior approaches for patients with specific risk factors.