The effect of autologous conditioned plasma on the treatment of focal chondral defects of the knee. An experimental study.

The purpose of the present study was to evaluate the effect of local application of Autologous Conditioned Plasma (ACP) on the treatment of full-thickness cartilage injuries of the knee. The hypothesis of the study was that ACP can enhance healing response of injured cartilage. A full-thickness chondral lesion on the weight-bearing area of the medial femoral condyle was performed in 30 sheep. Animals were divided into 2 groups, according to postoperative treatment: in group 1, weekly injections of ACP for five times were performed; in group 2, lesions were left untreated. Animals were sacrificed at 3, 6 and 12 months after treatment. A histological evaluation was performed according to a modified O'Driscoll histological score. Comparison between groups for each time interval was performed with the Student's t-test. Significance was set at P<0.05. A post-hoc power analysis was performed according to the hypothesis of the study. Histological evaluation at 3 and 6 months showed that group 1 had significantly greater total score than group 2. At 12 months, no significant difference was observed between groups. In conclusion, local injections of ACP for treatment of full-thickness cartilage injuries did not produce hyaline cartilage. However, it promoted reparative response of the cartilage defect until 6 months after treatment.