Figure 4

Correlation between GAG content and Young’s modulus, yield strength and ultimate strength. In Group 2 (with cartilage lesions), mechanical properties all correlated with GAG content. A, Young’s modulus positively correlated with GAG content (r=0.785, P=0.001). B, Yield strength positively correlated with GAG content (r=0.530, P=0.024). C, Ultimate strength positively correlated with GAG content (r=0.635, P=0.005). In Group 1 (without cartilage lesions), D, Young’s modulus positively correlated with GAG content (r=0.473, P=0.047). E, Yield strength not significantly correlated with GAG content (r=0.254, P=0.309). F, Ultimate strength not significantly correlated with GAG content (r=0.261, P=0.295). These figures indicate that decreased mechanical property of trabeculae may associated with the degradation of cartilage in osteoporosis patients with cartilage lesions.