High BMI alone did not raise early complication risk after outpatient TJA

Editor's Note

Patients with BMI 40 or higher had similar 24-hour and 1–90 day complication rates to lower-BMI patients after primary total joint arthroplasty (TJA) performed at an academic ambulatory surgery center (ASC), an August 25 article from The Journal of Arthroplasty reports. The study retrospectively analyzed 2,367 primary THA and TKA cases from January 21, 2021, to September 18, 2024, grouped by NIH/WHO BMI categories.

The article notes no significant differences in immediate complications (P=0.19) or complications between 1 and 90 days (P=0.63) across BMI groups. Multivariable analyses found BMI, as a continuous or categorical variable, was not an independent predictor of either 24-hour or 1–90 day complications. Instead, having a hip arthroplasty predicted 24-hour complications (odds ratio 3.41; 95% CI 1.11 to 12.70), and higher Charlson Comorbidity Index predicted 1–90 day complications (OR 1.22; 95% CI 1.05 to 1.40).

Operational metrics varied by BMI. Higher-BMI patients had longer preoperative holding, longer in-room time to incision for several subgroups, and longer operative times for both THA and TKA. Despite this, estimated blood loss did not differ by BMI, and higher-BMI patients spent less time in PACU but reported higher final PACU pain scores before discharge. Among specific 1–90 day events, only urinary tract infection rates differed, with normal-weight patients experiencing more UTIs than overweight patients on post hoc testing.

According to the article, the findings support individualized preoperative optimization and patient selection that consider comorbidities and functional status rather than rigid BMI cutoffs for ASC candidacy. The authors note limitations including the single-institution, retrospective design; smaller class 3 obesity sample; potential selection bias; and 90-day follow-up horizon.