Cartilage defects are associated with physical disability in obese adults

Objective. To describe the associations between physical disability measures and knee cartilage defects in obese adults. Methods. One hundred and eleven obese subjects were recruited from laparoscopic adjustable gastric banding or exercise/diet weight loss programmes. All subjects completed disease-specific (WOMAC) and general health status (SF-36) questionnaires, and were assessed for range of knee motion, tibiofemoral alignment and quadriceps strength. Knee cartilage defects were graded on MRI according to established protocol. Regression analysis was adjusted for age, gender, BMI and presence of clinical knee OA. Results. The association between higher whole compartment cartilage defect scores and increasing BMI, age and clinical knee OA was confirmed in this obese cohort (r = 0.27, P = 0.01; r = 0.26, P = 0.007; P < 0.0001, respectively), whereas new associations were found with reduced knee range of motion (r = 0.5, P < 0.0001). No associations were found between defect scores and quadriceps strength. Varus malalignment was associated with higher medial cartilage defect scores (r = 0.33, P = 0.013). Higher levels of pain, stiffness and physical disability (WOMAC, SF-36) were associated with higher medial compartment and patella cartilage defect scores. Conclusions. Knee cartilage defects increase with increasing obesity and are associated with both objective and self-reported measures of physical disability. Longitudinal studies are required to assess the potential for change or improvement in cartilage defects with weight loss.