The effect of body mass index on functional outcome in total knee replacement

Abstract

Background: Osteoarthritis is one of the leading causes of disability. TKR is the most common procedure for end stage arthritis. Although obesity is assumed to bring out a negative influence on survival of TKR, there is no definitive proof in literature. The impact of obesity on the outcomes of TKA is still debated. Aim: To investigate the effects of body mass index on the rehabilitation process in patients with a recent TKR. Design: This prospective study included patients (N= 50) who underwent TKR between 2018 and 2019 for primary OA. Materials and Methods: Patients undergoing TKR were identified from a prospective arthroplasty database. 50 patients were included in the study. Age, gender, BMI, pre- and post-operative functional scores [International knee society score: KSS], complications were recorded. WHO BMI classification was used to group the patients. The functional outcome of the normal weight group (BMI < 25) was compared to the overweight and obese group (BMI ≥ 25). Results: Mean age in the study was 65.8 (52-78). 60% (30) were female. The mean BMI was 28.8 (18-52). 70% of patients were either overweight or obese. Mean follow-up was 12.33 mo (6-24 mo). No significant difference was identified in pre or post-operative KSS in normal weight (BMI < 25) group compared with that of patients with a BMI ≥ 25. Overall, there was 1 case of infection (2%), with no complications or revisions in the normal weight group (BMI < 25) Conclusion: BMI did not show any influence on post-operative outcome comparing normal weight individuals and the ones with BMI > 25. Patients should not be denied total knee replacement based solely on BMI alone.