To better understand the effect of body weight on the course of knee OA, researchers at Boston University focused on an important predictor of disease progression: limb malalignment, defined by joint space loss at the point where the thigh and shin bones connect to the knee. Featured in the December 2004 issue of Arthritis & Rheumatism (http://www.interscience.wiley.com/journal/arthritis), their findings suggest that the benefits of weight loss for knee OA patients depend on the degree of alignment in the affected leg.
The researchers recruited their subjects from two studies on quality of life conducted by the Veterans Administration of the Boston Health Care System. 228 individuals with knee OA were selected; all but one completed a 30-month period of follow-up. 41 percent were women and the mean age was 66 years. Among the subjects, the diagnosis of OA was confirmed by radiographs in 394 knees. At the first follow-up examination, each subject was assessed for degree of alignment in the affected leg, which was then categorized as moderate, severe, or neutral. Malaligned limbs could be either varus (bowlegged) or valgus (knock-kneed). The body mass index (BMI) of each subject was also computed.