Description
Objective: Obesity is an epidemic and many surgeons use weight loss goals and body mass index (BMI) cutoffs when offering total hip arthroplasty (THA). However, little is known about who loses weight before THA and if weight loss provides tangible benefits. The goals of this study were to determine how many patients lose weight before THA, predictors of preoperative weight loss, and if preoperative weight loss improves outcomes.
Methods: Among 21,038 primary THAs performed between 2002 and 2019, we identified 2463 patients with preoperative BMIs>30 kg/m2 measured 1-24 months before surgery and a weight measured at surgery. The mean age was 66 years with 47% female. The mean BMI was 35 kg/m2. Univariable logistic and linear regressions and Cox proportional hazard models evaluated length of stay, operative time, complications, revisions, and reoperations among patients maintaining preoperative weight compared to those losing ≥10 pounds before surgery. Mean follow-up was 5 years.
Results: Overall, 45% lost ≥5 pounds, 29% lost ≥10 pounds, and 12% lost ≥20 pounds before THA. Younger patients (OR=1.1 per 10 years younger, p=0.002) and females (OR=1.1, p=0.24) were more likely to lose ≥10 pounds. When comparing those who lost ≥5 pounds, ≥10 pounds, or ≥20 pounds to those who maintained weight, there were no differences in 1-year, 2-year, 5-year, or 10-year survivorship free of infection, complication, revision, or reoperation. Across overall follow-up, losing ≥10 pounds was not associated with length of stay, operative time, complications, revisions, or reoperations.
Conclusions: Relatively few patients lose meaningful weight before THA, suggesting BMI cutoffs may be unrealistic goals for most patients. Patients who lose weight tend to be younger, but even those achieving common benchmarks for weight loss did not reduce postoperative risks. While weight loss benefits overall health, preoperative weight loss alone may not be enough to reduce postoperative risks.
