Fig. 3

Representative macroscopic features of the femoral condyle cartilage. In the untreated OA group and late injection group, cartilage erosion was observed at day 14, and bone destruction was evident at day 21 and progressed at day 28. In the late injection group, the cartilage surface was still glossy at day 28 (a). The scores were 2.9, 4.4, and 4.3 at days 14, 21, and 28 after injection, respectively. In the early injection group, the scores of the treated knees were lower than the control knees. Data are mean ± SD, P < 0.05, by one-way ANOVA, with Tukey’s post-hoc analysis (b)