Can weight loss improve osteoarthritis in obese patients?

There is an obvious correlation between how much you weigh and the resulting impact on your knees. The heavier you are, the more likely you are to have joint pain and arthritis. In this study a group of 157 obese patients (82% female, 18% male) received dietary counseling over 16 weeks in order to reduce their overall weight and to thereby study how knee joint loading changes due to weight loss.

The group lost 13.2% of their original body mass (approximately 13.7 kg, or 30 lbs), on average, and reduced their BMI by 13.8%. The peak compressive loads in the knee stayed the same, at about 2-4 times body weight. However, a few important measures of the mechanics of knee loading changed in a positive direction. The peak knee joint load was reduced by 2.2 kg for every 1 kg of weight lost and the knee abductor moment (KAM) saw a 12% decrease, which indicated a decrease in the total medial joint loading. The medial compartment (or internal part of the knee joint) is more commonly affected by osteoarthritis than its lateral counterpart, so reducing the absolute amount of weight-based load in this medial area bodes well for reducing knee osteoarthritis in overweight patients.

The best clinical result, though, was a 30% in reported joint pain after weight loss, which was further confirmed by a 4% increase in the self-selected walking speed, since patients will move more when they are in less pain. Researchers had to compensate for this increased walking speed in order to see the effects of weight loss on joint loading because higher walking speeds increase the loading of the knee joint.

Overall, the weight loss program had significant benefits to obese patients suffering from osteoarthritis of the knee. By reducing the total weight of their bodies, they improved their knee loading mechanics and pain scores. Losing 5.1 kg (11.2 lbs) and maintaining that loss can reduce the risk of developing OA by 50%. Now that is good reason to choose grilled chicken over a Big Mac.

Article Citation:
Aaboe, J. et al. “Effects of an intensive weight loss program on knee joint loading in obese adults with knee osteoarthritis”. Osteoarthritis & Cartilage Vol. 19, Issue 7, pp. 822-828.