Functional Outcomes with Primary Total Knee Replacement in Respect to Body Mass Index

Background: Osteoarthritis (OA) is a prevalent condition and the leading disability among the elderly. Obesity, linked to a sedentary lifestyle, increases the risk of OA. Knee Osteoarthritis has improved functional outcomes after Total Knee Replacement (TKR). This study aimed to determine the functional outcomes of primary TKR based on BMI. Methods: This Prospective Cohort Study, was conducted at Dr Ziauddin Hospital Karachi, from October 2019 to October 2020. Patients of both genders, above the age of 45 years, with knee joint osteoarthritis grade III and IV advised primary TKR, were included. Functional outcomes were assessed using the Knee Society Score, preoperatively and postoperatively, in obese and non-obese groups. The non-probability Convenience Sampling technique was used. SPSS v25.0 and Microsoft Excel 2016 were used for analysis. Chi-square and t-tests were applied, with significance set at p < 0.05. Results: The study included 98 knees in 66 cases, with 30 patients in the obese group and 36 patients in the non-obese group. In the obese group, 28 (93.3%) were over 60 years old, compared to 35 (97.2%) in the non-obese group. The obese group had 23 (76.7%) female patients, while the non-obese group had 22 (61.1%). Postoperative Knee Society Scores were 84.83±4.71 for the obese group and 87.08±4.07 for the non-obese group. Excellent functional outcomes were achieved by 17 (56.6%) obese and 22 (61.1%) non-obese patients. Conclusion: BMI should not exclude patients from TKR, but they should be informed of the associated risks, considering the difference in postoperative functional outcomes in both groups.