The Impact of Preoperative Weight Loss Timing on Surgical Outcomes in Total Hip Arthroplasty

Abstract

Background: Elevated body mass index (BMI) increases surgical complications post-total hip arthroplasty (THA). However, the effects of rapid weight loss pre-THA remain unclear. This study evaluated patients who had initial BMIs between 40 and 50, and then achieved a BMI under 35 at various intervals before their THA. Comparisons were made with consistent obese and nonobese groups to understand potential complications.

Methods: Using a national database, we categorized THA patients based on initial BMI and weight loss timing before the surgery. These were contrasted with those maintaining a steady BMI of 20 to 30 or 40 to 50. We monitored outcomes like periprosthetic joint infections (PJI), surgical site infections (SSI), and noninfectious revisions for 2 years postsurgery, incorporating demographic considerations. Statistical analyses utilized Chi-square tests for categorical outcomes and Student's t-tests for continuous variables.

Results: Among patients who had a BMI of 45 to 50, weight loss 3 to 9 months presurgery increased PJI risks at 90 days (Odds Ratios [OR]: 2.15 to 5.22, P < .001). However, weight loss a year before the surgery lowered the PJI risk (OR: 0.14 to 0.27, P < .005). Constantly obese patients faced heightened PJI risks 1 to 2 years postsurgery (OR: 1.64 to 1.95, P < .015). Regarding SSI, risks increased with weight loss 3 to 9 months before surgery, but decreased when weight loss occurred a year earlier. In the BMI 40 to 45 group, weight loss 3 to 6 months presurgery showed higher PJI and SSI at 90 days (P < .001), with obese participants consistently at greater risk.

Conclusions: While high BMI poses THA risks, weight loss timing plays a crucial role in postoperative complications. Weight loss closer to the surgery (0 to 9 months) can heighten risks, but shedding weight a year in advance seems beneficial. Conversely, initiating weight loss approximately a year before surgery offers potential protective effects against postoperative issues. This highlights the importance of strategic weight management guidance for patients considering THA, ensuring optimal surgical results and reducing potential adverse outcomes.

Keywords: body mass index; periprosthetic joint infection; postoperative complications; surgical site infection; total hip arthroplasty; weight loss timing.