The Impact of Preoperative Weight Loss on 90-Day Complications Following Primary Total Knee Arthroplasty

Background Access to primary total knee arthroplasty (TKA) for morbidly obese (MO) patients is often restricted to reduce complications. We compared complication rates in patients who were MO or non-MO (NMO) at initial presentation based on whether their body mass index (BMI) had decreased by ≥5%, remained stable, or increased by ≥5% at the time of surgery, hypothesizing that preoperative weight loss does not reduce complication rates. Methods Prospectively collected data for 2219 unilateral, primary TKAs were retrospectively reviewed. Cases were performed between 2012 and 2023 at the same academic center by 4 fellowship-trained surgeons using standardized protocols. Twenty-eight percent (n = 627) were MO and 72% (n = 1592) were NMO at initial presentation. Outcomes included intraoperative and 90-day complications and reoperations. Outcome covariates included patient demographics and comorbidities, as well as operative details. Independent samples t -tests and chi-squared tests were used for statistical analysis. Results Intraoperative complications ( P = .999), medical complications ( P ≥ .398), death ( P = .299), superficial or deep infection ( P = .731), and reoperation on the index joint within 90 days of surgery ( P = .801) did not differ in MO patients with a ≥5% decrease vs stable BMI before surgery. These outcomes also did not differ between NMO patients with a ≥5% decrease in BMI and those with stable BMI before surgery ( P ≥ .250). Conclusions Findings suggest that withholding surgery from patients who are clinically indicated for TKA pending weight loss may not be necessary to reduce early postoperative complications.