Every orthopedic physical therapist is confronted with the obese patient who is 80-100 pounds overweight and has osteoarthritis of the knees. After performing hundreds of straight leg raises along with other strengthening exercises, along with nonweightbearing activities such as cycling, and aquatic therapy, they too often continue to complain of knee pain. The reality is, until this patient unloads their weight-bearing joints they are not likely to experience any significant reduction in pain.
The subject of weight loss is often a difficult and sensitive one to bring up with your obese patient; however there are ways that you can present factual information and encourage your patient to make strides toward a decision of weight loss. I use an informational handout which highlights the relationship with osteoarthritis of the knees and body weight. I emphasize for every pound of body weight that they lose there is an equivalent reduction of 4 pounds of forces on their knee, and a 30% reduction in pain and 24% improvement in function with as little as 12 to 15 pound reduction in weight. I also appeal to my patient explaining studies have shown weight loss will decrease cartilage degeneration. Those that had the greatest weight loss during the study had the least amount of cartilage degeneration. In one study, those women of average height, for every 11 pound weight loss the risk of knee osteoarthritis dropped by about 50%.
However knowledge alone will not change behavior, so the second step would be to encourage them to make a decision to lose weight. You might ask them to write down all the benefits of being at a lower body weight. Then ask them to select 3 to 4 reasons which are most important to them. These might be to walk without knee pain, reduce their blood pressure medication, and be able to play with their grandchildren. You can then offer to help them set a realistic weight loss goal. Research suggests 5 to 10% reduction in their current body weight will significantly improve parameters of health. In my next article I will address how you might encourage behavioral changes that would facilitate weight loss.