OBJECTIVETo investigate whether the unevenness of articular surface would affect the osteochondral repair.

METHODSEight Shanghai Chongming 6-months-old masculine goats with a mean weight of 25 kg were used in this study. Different unevenness, which were 0.5 mm, 1.0 mm, 2.0 mm protrude or concavity, were created on the weight-bearing portion of the medial femoral condyles of the goats. The goats were sacrificed 12 weeks later and were observed with the general observation, HE staining and transmission electron microscope. To evaluate the microscopic morphology, a histological grading scale described by O'Driscoll, Keeley and Salter was used.

RESULTSThe general observation and HE staining showed that the unevenness of 0.5 mm or 1.0 mm protrudes or concavity could be repaired to get the surface smooth on the whole. The transmission electron microscope showed that the reparative tissues were the same as the normal cartilage. The 2.0 mm depth couldn't be repaired satisfactorily. The transmission electron microscope showed that the fiber bundle proliferated and the chondrocytes degenerated. The scores of the 2.0 mm depth were significantly lower than that of the 0.5 mm or 1.0 mm (P < 0.05).

CONCLUSIONThe unevenness could have an influence on the repair. The limited unevenness could be repaired by itself.