Figure 3

Macroscopic findings. A full-thickness osteochondral plug of 5 mm in diameter and 7 mm in depth was harvested from the patellar groove. Articular cartilage around the hole was shaved in a 7 × 7 mm square until bleeding from the subchondral bone was observed. The harvested plug was then returned precisely to its original site. (a) At day 0, the plug was intact and the margin around the plug and the shaved square was clearly recognizable. (b) At 2 weeks postoperatively, the margin around the square could be clearly detected. Although the articular surface of the plug was smooth and regular, the plug had subsided a little. (c) The margin around the plug and the shaved square could be easily detected at 4 weeks. (d) At 8 weeks postoperatively the margin was a little faint but could still be detected. At 4 (panel c) and 8 weeks (panel d), the site around and over the plug was filled with newly formed reparative tissue. Although the surface of the plug and the defect looked irregular, the plug was glossy. (e) The margin around the plug and the shaved square was a little faint but could still be detected at 12 weeks. (f) At 24 weeks postoperatively, however, the margin was very faint. The plug survived well and osteoarthritic changes such as osteophyte formation were not observed at 12 and 24 weeks postoperatively (panels e and f). The surface of the plug cartilage was as smooth as that of the adjacent intact cartilage.