Comparative Efficacy of Posterolateral versus Lateral Approach in Total Hip Arthroplasty: A Retrospective Cohort Study on Prosthetic Alignment and Stability

This single-center retrospective cohort study evaluated the biomechanical and clinical outcomes of the posterolateral approach (PLA) compared to the lateral approach in total hip arthroplasty (THA). A cohort of 270 patients undergoing primary THA via PLA was analyzed, with prosthetic alignment parameters (acetabular inclination, acetabular anteversion, femoral stem anteversion, and combined anteversion) quantified using postoperative CT imaging. Results demonstrated statistically significant increases in acetabular component inclination (48.09°±8.54° vs43.2°±8.7°, p <0.05), acetabular anteversion (29.09°±9.06° vs.18.4°±6.9°, p <0.01), femoral stem anteversion (19.28°±11.28°vs. 14.6°±7.3°, p <0.05), and combined anteversion (48.37°±13.04°vs. 32.0°±10.5°, p <0.01) compared to historical lateral approach data. Notably, no postoperative dislocations were observed in the PLA cohort (0% incidence), attributed to standardized capsular repair and component positioning protocols. Despite only 19.35% of cases achieving dual-axis Lewinnek "safe zone" alignment, meticulous soft tissue reconstruction ensured stability even with elevated combined anteversion (range: 22.18°–75.44°). These findings highlight the biomechanical adaptability of PLA in optimizing prosthetic positioning while maintaining stability, particularly in anatomically complex cases. Methodological rigor, including uniform surgical protocols and CT-based measurements, minimized confounding variables. This study supports PLA as a robust approach for THA, balancing alignment flexibility with clinical safety.