CARTILAGE AND SPORTS

Articular cartilage has a very limited healing potential, in particular because of the low mitotic activity of chondrocytes as well as its avascular nature. Therefore once injury occurs it is essential to restore a smooth surface which enables smooth motion of bone and the ability to withstand extreme amounts of pressures.

Articular cartilage injuries of the knee have been increasingly identified as a cause of functionally limiting injuries, especially in athletes. Chondral injuries may be isolated defects but are frequently found in association with other internal derangements such as meniscal tears, anterior cruciate ligament (ACL) damage, patellar dislocation, or osteochondritis dissecans (OCD). Physical demands can result in acute injury such as chondral fractures from shear and/or compression forces, or repetitive submaximal micro-trauma in high-impact, rapid deceleration and pivoting/cutting/directional change sports. In addition to acute cartilage trauma, subchondral bone bruises are present in up to 80% of the ACL injured knees acting as a cause of persistent pain and progressive cartilage degeneration.  Repetitive cartilage trauma due to pathologic high rate loading speeds up its destruction. Furthermore, high intensity exercise has been shown to decrease cartilage proteoglycans content and cause chondrocyte apoptosis leading to progressive chondropenia.