Methods: A prospective study was conducted in which we included patients undergoing unilateral/bilateral TKR for primary osteoarthritis. The patients were assessed clinically, functionally and radiologically pre-operatively and post-operatively using knee society score (KSS).We compared non-obese, obese, morbidly-obese patients using statistical analysis.

Result: We had 105 non-obese(151 knees) and 148 obese patients(151 knees). The mean BMI(kg/m²) of non-obese, obese and morbidly-obese patients were 24.29, 33.66 and 41.66 respectively. Pre-operative Knee Clinical score(KCS) 31.77 and Knee functional score(KFS) 39.19 in obese patients was much lower than pre-operative KCS 39.58 and KFS 47.9 in non-obese patients. Post-operative mean KCS and KFS in obese patients was 80.55 and 78.23 while in non-obese patients it was 89.58 and 86.29 respectively. Statistically there was a significant difference (P< 0.001) in all the categories amongst obese, non-obese and morbidly-obese. Complications included a superficial infection, deep infection, wound dehiscence and DVT.

Conclusion: Knee arthroplasty in obese(especially morbid) patients results in an overall lower functional score and more wound complications than the non-obese. However, change of pain score & satisfaction were comparable with the non-obese patients. All the obese patients had significant improvements in quality of life compared to their pre-operative status.