Background: Osteoarthritic patients needing a TKA give pain as the major reason for being unable to exercise to lose weight. Weight gain in turn worsens the process of osteoarthritis, this feeds into the vicious cycle. Following a TKA, patients should ideally be able to exercise more and hence lose weight. We assessed this hypothesis in our prospective study by calculating BMI. BMI has been proven in previous studies to be a good reflection of body fat.

Materials and Methods: We prospectively followed up 94 patients in the knee arthroplasty clinic. Height, pre operative weight and post operative weight at 12 months were measured. All the peri-operative factors in all the patients were constant. We then calculated the pre and post operative BMI.

Results: Most of our patients at the 12 month follow up showed to have an increase in BMI. This difference was however not found to be statistically significant.

Conclusion: The result obtained in our study was contrary to previous studies which have shown significant change. We conclude that pre-operative pain alone is not a limiting factor in patient BMI changes peri-operatively.