Role of body mass index on total knee replacement rehabilitation and outcome

Abstract

Aim: To evaluate the effect of body mass index on functional outcome in total knee replacement. Materials and methods: This is a prospective study conducted in Katuri medical college and hospital, Guntur; from November 2017 to November 2019 for total knee replacement. Total 50 patients were included. Age, gender, pre-operative body mass index, pre-operative and post-operative functional scores [International knee society score: KSS], complications were recorded. Based on WHO BMI classification patients were grouped. The functional outcome of the normal weight group (BMI < 25) i.e. group 1 was compared to the overweight and obese (BMI ≥ 25) group i.e. group 2. A separate sub-group analysis was performed to compare all five WHO BMI groups’ i.e. Normal weight, overweight, class 1, 2&3 obese. Results: With a mean age of 65.8 (52-78), 50 primary total knee replacements were included. 60% (30) were female. The mean body mass index was 28.8 (18-52). Seventy percent of patients were either overweight or obese. Follow-up was 1 year. There was no statistically significant difference in pre or post-operative KSS in the normal weight (BMI < 25) group compared to patients with a BMI ≥ 25 (P > 0.05). Sub-group analysis revealed poorer KSS in class 2 obese (74.8) compared to overweight (86.4) and class 1 obese (82.2). Overall there was 1 case of infection (2%) in obese group with no complications in the normal weight group. Conclusion: Post-operative functional outcome was not influenced by BMI comparing normal weight ones with the ones in overweight or underweight category. So, there is no need to deny TKR basing on weight alone.