Impact of diabetes mellitus and preoperative body mass index on 30-day postoperative complications and readmissions following total knee arthroplasty.

Objectives: This study aims to evaluate 30-day postoperative complications and hospital readmissions across different body mass index (BMI) categories and diabetic statuses following primary total knee arthroplasty (TKA).

Patients and methods: Between January 2013 and December 2022, a total of 502 patients (100 males, 402 females; mean age: 68.8±7.7 years; range, 45 to 91 years) who underwent primary TKA for knee osteoarthritis were retrospectively analyzed. Data collected included basic demography, BMI, diabetes mellitus (DM) status, and 30-day postoperative complications such as venous thromboembolism (VTE), infections, neurological events, cardiac events, and renal issues. Readmissions due to operative or medical complications were recorded.

Results: Of the patients, 141 (28.1%) had DM and 186 (37.1%) patients were classified as obese. The obese group experienced the highest incidence of VTE (1.6%), whereas overweight patients exhibited a higher rate of renal events (1.0%). All non-diabetic underweight patients (n=2) developed postoperative hypoglycemia. Diabetic patients had significantly increased odds of VTE compared to non-diabetics (odds ratio=6.74; p=0.009). Normal BMI diabetic patients demonstrated the highest incidence of surgical site infections (7.4%), while normal BMI non-diabetic patients were more prone to foot drop (1.1%) and cardiac events (4.5%).

Conclusion: Elevated BMI and DM independently or in combination, contribute to higher rates of postoperative complications and readmissions following TKA.