Is Direct Anterior Approach Associated With a Compromise of Femoral Stem Survival After Total Hip Arthroplasty? A Regional Registry-Based Analysis

Introduction: The direct anterior approach (DAA) for uncemented total hip arthroplasty (THA) has been advocated for early functional recovery, yet concerns persist regarding its influence on femoral component survival. We analysed a large regional registry to compare implant survivorship and the risk of aseptic femoral loosening between DAA and conventional direct lateral/posterolateral (DL-PL) approaches. Materials and methods: We conducted a retrospective cohort study of 30,753 primary uncemented THAs recorded in the Emilia-Romagna Prosthetic Implant Registry (RIPO) from January 2009 through December 2021. Procedures were classified by surgical approach as DAA (n = 7,663) or DL-PL (n = 23,090). Demographic variables, implant characteristics (including stem length), and reasons for revision were extracted. Kaplan–Meier analysis estimated cumulative survivorship for any-cause revision and for revision due to aseptic loosening; group differences were assessed with the log-rank test. Multivariable Cox proportional hazards models, stratified by age (< 65 vs ≥ 65 years) and adjusted for sex and stem length, evaluated the independent effect of surgical approach on aseptic revision risk. Median follow-up was 4.6 years (IQR 2.3–7.65). Results: Patients undergoing DAA were slightly younger (mean 67.6 ± 10.4 vs 69.6 ± 9.8 years; p < 0.001), less frequently obese (21.5% vs 28.7%; p < 0.001), and more often received short femoral stems (58.6% vs 24.8%; p < 0.001). DAA utilization increased markedly over the study period. Twelve-year cumulative survivorship for all-cause revision was high and similar between groups (DAA 95.6%, 95% CI 94.5–96.7; DL-PL 94.9%, 95% CI 94.4–95.5; log-rank p = 0.554). For aseptic loosening, 12-year survivorship was also comparable (DAA 98.9% vs DL-PL 98.4%; p = 0.562). In age-stratified adjusted Cox models, surgical approach was not an independent predictor of aseptic revision (age < 65: HR 0.81, 95% CI 0.46–1.44; age ≥ 65: HR 1.32, 95% CI 0.77–2.26). Conclusions: In this large registry-based series, the DAA was not associated with inferior long-term implant survivorship or a higher risk of aseptic femoral loosening compared with DL-PL approaches after adjustment for patient and implant factors. These findings indicate that, at a population level and with appropriate case and implant selection, DAA yields mechanical outcomes comparable to traditional approaches.