Association between body mass index and early clinical efficacy and complications after total knee arthroplasty

This study aims to investigate the association between body mass index (BMI) and early postoperative clinical efficacy and complication rates in patients undergoing total knee arthroplasty (TKA), thereby providing evidence for perioperative management. Clinical data of 100 patients who underwent TKA were retrospectively analyzed. Patients were classified into a non-obese group (NOG, BMI < 28 kg/m², n=43) and an obese group (OG, BMI ≥ 28 kg/m², n=57) based on BMI. The two groups were compared in terms of perioperative surgery-related parameters, knee joint function scores (HSS and KSS scores), joint range of motion (ROM), pain intensity (VAS scores), inflammatory markers (CRP and ESR), postoperative radiographic indicators, and incidence of complications. No statistically significant differences were observed in the baseline characteristics (sex, age, ASA classification, etc.) between the two groups (P>0.05), indicating good comparability. The OG demonstrated significantly longer operation time, greater intraoperative blood loss, longer tourniquet time, longer hospital stay, and higher drain output than the NOG (P<0.05). The HSS and KSS scores of the NOG at 3 and 6 months postoperatively were significantly higher than those of the OG (P<0.05). The NOG exhibited significantly greater ROM and lower VAS scores at each postoperative time point compared with the OG (P<0.05). The levels of CRP and ESR in the NOG at 24 and 72 hours postoperatively were significantly lower than those in the OG (P<0.05). The OG showed significantly greater hip-knee-ankle (HKA) angle deviation and patellar tilt angle compared with the NOG (P<0.05). The overall incidence of complications in the NOG was lower than that in the OG (11.63% vs. 42.11%, P<0.05). Higher BMI was associated with delayed early functional recovery, increased inflammatory stress responses, and a higher risk of postoperative complications after TKA. Clinicians should pay attention to preoperative weight management and implement individualized perioperative interventions to improve early postoperative recovery.