Body Mass Index Above 35 Has Increased Risk of Complications but Still Achieves Clinically Meaningful Improvement in Patient-Reported Outcomes After Anterior-Based Total Hip Arthroplasty

Background

Increased perioperative complications in obese patients undergoing total hip arthroplasty (THA) have previously been reported. There is a relative paucity of data evaluating these complications strictly in the context of anterior-based THA. In this study, we compare the outcomes following anterior-based THA as a function of body mass index (BMI).

Methods

A 1:1 matched retrospective cohort study was conducted. Patients undergoing anterior-based THA from January 2022 to June 2024 with a BMI >35 kg/m² were matched 1:1 based on age and sex to patients with a BMI <35 kg/m² from our division registry. Demographic data, surgical details, complications (intraoperative and postoperative), and patient-reported outcome measures (PROMs: 12-Item Short Form P/M, Western Ontario and McMaster Universities Osteoarthritis Index-P/S/F) were collected and analyzed.

Results

There were 280 patients included (140 per group). There were 27 postoperative complications in the BMI >35 kg/m² group and 10 in the BMI <35 kg/m² group (P < .01). There were 10 major complications (4 dislocations, 2 periprosthetic fractures, and 4 deep infections requiring incision and drainage) in the BMI over 35 kg/m² group, with no major complications occurring in the lower BMI group. There were 3 intraoperative complications (periprosthetic fracture), all in patients with BMI >35 kg/m². There was significant improvement in Western Ontario and McMaster Universities Osteoarthritis Index P/S/F scores and 12-Item Short Form pain in both groups at 3 months postoperatively, with greater improvements seen in the BMI >35 kg/m² group.

Conclusions

The present study found that despite significant differences in postoperative complications, there were significant improvements in PROMs in patients with a BMI above and below 35 kg/m² who underwent anterior THA.