Fig. 2.

Histomorphometric knee osteoarthritis (OA) scores for 17-mo-old Col9a1^−/− mice and WT mice. A: modified Mankin OA score, expressed as a percent of the maximum score, for each graded site in the knee joint. Col9a1^−/− scores were significantly greater than WT scores in the medial femur and lower in the lateral tibia. B: cartilage structural degeneration score, a subcomponent of the Modified Mankin score, for each graded site in the knee joint. Col9a1^−/− mice had significantly greater cartilage degeneration than WT mice in the medial compartment, while there was no significant difference in degeneration in the lateral compartment. Values are means ± SE.