Prognostic factors predicting outcomes after total hip arthroplasty for femoral neck fractures; a multicentre retrospective cohort-study

OBJECTIVES: Fractures of the femoral neck (FFN) are a significant public health problem in an ageing population. Treatment options for FFN include head-sparing procedures with internal fixation, although there is a risk of conversion to total hip arthroplasty (cTHA) if internal fixation fails. Primary total hip arthroplasty (pTHA) is recommended for vital elderly patients with fully displaced FFN and/or with preexisting osteoarthritis. This study aims to identify prognostic factors that predict the risk of postoperative complications and revision for THA in patients with a FFN using a prediction model. METHODS: A multicentre retrospective cohort study was conducted in 5 hospitals in the Netherlands. Patients receiving a primary or conversion THA after FFN from 2006 until 2022 were included in the study. Multivariate regression analysis was used to develop a prediction model to identify predictive factors for risk of postoperative complications and revision. RESULTS: In total, 747 patients with THA after FFN were included. 18% of the population developed one or more major complications and 6.6% had a revision after THA within 4.6 years. From the multivariate regression analysis, we found male gender (odds ratio [OR] 2.1 (95% confidence interval (CI) 1.3-3.4)) was the only predictor for postoperative major complications. Male gender (OR 2.2; 95% CI, 1.0-4.7), ASA III classification (OR 7.4; 95% CI, 1.5-36.0) and cementless stem fixation (OR 2.4; 95% CI, 1.1-5.2) were predictive for revision. CONCLUSIONS: Male gender is associated with a higher risk of major complication and revision in THA after FFN. ASA III and cementless stem fixation are associated with a higher risk of revision of THA after FFN.