1. Reparative changes in surgical defects of the central non-weight-bearing articular cartilage of the knee joints of puppies have been studied and compared with the reparative changes in similar lesions in the adult dog.
2. These comparative studies indicate that the repair of surgically created articular-cartilage defects in similar areas of the joint is no more rapid or complete in young puppies before closure of the epiphysis than it is in adult dogs.
3. The proliferative activity of cartilage cells is greater in the deeper zones of articular cartilage than it is in the more superficial zones.
4. More active proliferation of cartilage cells was noted in lesions in which crevices existed. This finding indicates that the friction generated by the movement of the patella over the defect may be inhibitory to repair by independent proliferation of cartilage cells.
5. The presence of patellar-groove defects is not a cause of important intra-articular pathology.
(C) 1935 All Rights Reserved.The Journal of Bone and Joint Surgery, Inc.