Risk factors for femoral stem fracture following total hip arthroplasty: a systematic review and meta analysis

Background Femoral stem fracture following total hip arthroplasty (THA) is an infrequent but nevertheless devastating complication, with an increasing worldwide prevalence as demand for primary THA continues to increase. The aim of this study was to perform a systematic review and meta-analysis of risk factors for femoral stem fracture to help identify at risk patients. Methods A systematic search was conducted on EMBASE, MEDLINE and AMED to identify relevant studies. Data regarding study design, source, population, intervention, and outcomes was collated. Data extraction was performed on a custom form generated using Cochrane recommended methodology and analysis of risk factors performed including odds ratios (ORs) with 95% confidence intervals (CIs). Results A total of 15 studies reporting a total of 402 stem fractures in 49 723 THAs were identified. The median time from index procedure to stem fracture was 68 months (IQR 42.5-118) whilst mean age at index surgery was 61.8 years (SD 6.9). Male gender (OR = 3.27, 95% CI = 2.59-4.13, p < 0.001), patient weight above 80 kg (OR = 3.55, 95% CI = 2.88-4.37, p < 0.001), age under 63 years (OR = 1.22, 95% CI = 1.01-1.49, p < 0.001), varus stem alignment (OR = 5.77, 95% CI = 3.83-8.7, p < 0.001), use of modular implants (OR = 1.95, 95% CI = 1.56-2.44, p < 0.01) and undergoing revision arthroplasty (OR = 3.33, 95% CI = 2.70-4.1, p < 0.001) were significant risk factors for prosthetic stem fracture. A risk window of 15 years post-surgery was identified. Conclusions This review concludes that patient weight, younger age, male sex, varus stem alignment, revision arthroplasty and use of modular stems are significant risk factors for femoral stem fracture. Modifying these risk factors where possible may help reduce incidence of femoral stem fracture in at risk patients.