The Body Mass Index (BMI) and rehabilitation outcome in patients with degenerative changes of the knee joint

Background. Given that obesity is the primary risk factor and pain the primary symptom of degenerative disease of the knee joint, we undertook to study the dependency between the Body Mass Index (BMI) and pain symptoms, and the impact of the BMI on the outcome of rehabilitation. Material and methods. Our research involved 38 patients with bilateral degeneration of the knee joint, according to the of the American College of Rheumatology (ACR). The patients were examined twice: at baseline before rehabilitation and immediately after a series of 10 procedures, as follow-up. Body build in terms of obesity was assessed on the basis of the BMI, according to WHO norms. The level of pain with and without loading on the limb was taken as the criterion for evaluating rehabilitation outcome. Pain level was evaluated using Likert's 11-point scale. Results. There was a statistically significant correlation (p<0.05 at baseline and p<0.01 at follow-up) between the BMI and the level of pain under load, but no significant correlation between BMI and pain when there was no load on the limb. The outcome was better in patients whose BMI was in the normal range or only somewhat above. Conclusions. Pain symptoms, especially when the limb is bearing weight, is significantly dependent on the BMI, which also has a major impact on rehabilitation outcome. Normalizing body weight should be a first-order priority in both the prevention and the rehabilitation of degenerative changes in the knee.