Predictors of Conversion Total Hip Arthroplasty After Surgically Managed Acetabulum Fractures

Operative management of acetabular fractures can be complicated by the development of symptomatic post-traumatic arthritis, which may necessitate conversion total hip arthroplasty (THA). There is increased interest in treatment with THA for acute management, but optimal patient selection depends on identifying those at risk of later symptomatic post-traumatic arthritis requiring conversion THA. We systematically reviewed prognostic factors associated with conversion THA in adult patients with operatively managed acetabulum fractures. We searched MEDLINE and EMBASE from inception to September 27, 2024. Screening, data extraction, risk of bias assessment, and evidence grading were completed in duplicate. Data were pooled using a random-effects model to produce summary odds ratios (ORs), hazard ratios (HRs), and mean differences, with 95% confidence intervals (CIs). Risk of bias was assessed using the Quality in Prognosis Studies tool. Certainty of evidence was evaluated using the Grade of Recommendation, Assessment, Development, and Evaluation framework. A total of 3,054 citations were screened, and 38 studies (6,931 fractures) met inclusion criteria. Eight factors were associated with conversion THA in unadjusted analyses: acetabular impaction (OR 2.08, 95% CI 1.60-2.70, moderate certainty), femoral head impaction (OR 2.70, 95% CI 1.80-4.06, moderate certainty), dislocation (OR 2.20, 95% CI 1.51-3.19, moderate certainty), nonanatomic reduction on radiography (OR 2.36, 95% CI 1.58-3.51, moderate certainty), nonanatomic reduction on computed tomography (OR 3.46, 95% CI 1.25-9.57, moderate certainty), associated fracture type (OR 1.76, 95% CI 1.29-2.41, moderate certainty), female sex (OR 1.48, 95% CI 1.15-1.88, moderate certainty), and posterior wall involvement (OR 1.82, 95% CI 1.18-2.80, moderate certainty). In multivariable analyses, age (adjusted OR 1.04, 95% CI 1.02-1.06, high certainty; adjusted HR 1.04, 95% CI 1.03-1.05, high certainty) and femoral head impaction (adjusted HR 3.19, 95% CI 1.16-8.75, moderate certainty) were associated with conversion THA. The weighted proportion of patients requiring THA conversion was 17.6% (95% CI 15.2%-20.4%, low certainty). Older age and femoral head impaction were the only factors associated with conversion to THA in univariable and multivariable analyses. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.