RESUMEN
BACKGROUND: The influence of surgical approach on risk of early postoperative mechanical complications after total hip arthroplasty (THA) continues to be a focus of debate. We performed the first single-institution study on risk of early operative and nonoperative mechanical complications after THA based on approach, with the hypothesis that there would be no clinically significant difference with modern surgical methods. METHODS: A retrospective study was conducted on 16,186 consecutive THA performed from 2010 to 2016. Revision or conversion THA and cases performed for hip fracture, with recalled prostheses, or during a surgeon's learning period were excluded. THAs were performed using direct anterior (DA; n = 5465), direct lateral (DL; n = 8561), or posterolateral approach with soft tissue repair (PL; n = 2160). All mechanical complications within the first 2 years were identified. The primary analysis was a time to event Cox regression, accounting for both patient and surgeon characteristics. RESULTS: Compared with the DL approach, risk of mechanical complications was higher for both DA and PL. Adjusted risk of instability within 2 years was 0.17%, 0.74%, and 1.74% for DL, DA, and PL, respectively. While occurring at similar rates with the PL and DL approaches, the risk of periprosthetic fracture and loosening increased with DA. Consequently, femoral failure, including fracture or loosening, occurred more frequently for DA, with an adjusted incidence of 1.20% vs 0.58% and 0.47%, with DL and PL. CONCLUSION: Even with soft tissue repair, instability continues to occur with increased frequency with the PL approach. While reducing dislocation, a higher risk of femoral failure with DA must also be considered. Nevertheless, the DL approach appears to confer the lowest overall risk of mechanical complications.