The repair of osteochondral defects using an exogenous fibrin clot

To evaluate the ability of an exogenous fibrin clot to hasten or optimize the repair of full-thickness articular cartilage defects, 4-mm diameter, full-thickness articu lar cartilage defects in 20 adult mongrel dogs were packed with an exogenous fibrin clot that had been prepared from each animal. The defects were created in a loaded and unloaded portion of the femoral troch lea. The healing response was then examined using routine histology at various intervals from 2 weeks to 6 months.

Both the experimental (clot-filled) and control (empty) defects healed through a proliferation of fibrous con nective tissue that eventually modulated into fibrocar tilage. However, in the 2-, 4-, and 8-week animals, the experimental defects (both loaded and unloaded) dem onstrated a more organized and advanced healing re sponse than did the control defects. This difference was less pronounced in the 12- and 24-week animals. In all specimens, the clot-filled defects healed more uniformly than controls with less surface depression. In general, the unloaded sites were more uniform in heal ing than the corresponding loaded sites.