The impact of obesity on functional outcomes in navigation-assisted total hip arthroplasty.

INTRODUCTION

Functional outcomes after total hip arthroplasty (THA) are generally poorer in obese patients compared to non-obese individuals. However, the effect of obesity on functional improvement following navigation-assisted HA remains controversial. This study investigates whether BMI influences functional outcome improvements following navigation-assisted THA.

MATERIALS AND METHODS

We reviewed our institutional database from 2010 to 2024 for patients undergoing navigation-assisted unilateral primary THA. Patients were categorized as Healthy weight (18.5-25.0 Kg/m2), Overweight (25.0-29.9 Kg/m2), and Obese (30-39.9 Kg/m2), based on their preoperative BMI. Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) was compared across BMI groups as the primary outcome. Multiple linear regression models were used to investigate the effect of BMI groups on Delta HOOS JR and postoperative HOOS JR while controlling for confounding variables.

RESULTS

A total of 1,543 cases with a mean age of 62.80 years (range: 23-94) were included. Most patients were Overweight (40.5%), followed by Obese (32.9%) and Healthy weight (26.6%). Although obese patients had significantly lower preoperative and postoperative functional scores (p < 0.05), they demonstrated greater improvements in HOOS symptoms (44.68 ± 22.45 vs. 40.68 ± 22.29, p = 0.006) and activities of daily living (46.36 ± 20.85 vs. 42.10 ± 21.20, p = 0.002) compared to the Healthy weight group. Despite obesity being linked to lower postoperative HOOS JR, regression analysis showed age ≥ 60 years, men, and alcohol consumption-but not BMI status-negatively affected Delta HOOS JR.

CONCLUSIONS

The obese group exhibited better improvements in HOOS symptoms and ADL with comparable Delta HOOS JR, supporting navigation-assisted THA as a valuable option for obese patients. The results of this study may help surgeons provide evidence-based preoperative counseling to obese patients regarding the expected clinical outcomes of THA.