Impact of Body Mass Index and Radiographic Parameters on Complications and Operative Times Comparing Anterior and Postero-lateral Approaches

BACKGROUND: As total hip arthroplasty (THA) continues to grow in the United States, so does patients' body mass index (BMI). This study evaluated links between BMI, operative times, complications, and radiographic parameters in THA using direct anterior (DAA) and postero-lateral (PL) approaches. METHODS: Of 2,088 THAs performed between 2017 and 2021 at a single academic institution, 998 met the inclusion criteria: DAA (n = 640) and PL (n = 358). Operative times, complications, and radiographic parameters were analyzed. The mean BMI was 29.5 for DAA and 31.1 for PL, and 38 had a BMI greater than 40. RESULTS: Body mass index was not associated with postoperative fractures or dislocations. Each point increase in BMI was linked to the addition of 0.42 min to operative times for PL (confidence interval: 0.16 to 0.67, P = 0.001) and a 19% increase in the odds of infection for DAA (odds ratio: 1.19, confidence interval: 1.03 to 1.38, P = 0.02). Radiographic measurement showed no relationship with complications. CONCLUSIONS: Elevated BMI was associated with an increased risk of infection for DAA and longer operative times for PL. Radiographic parameters were not predictive of postoperative outcomes. These results demonstrate positive outcomes across approaches, although tradeoffs were evident in patients who had elevated BMIs.