Osteochondritis dissecans (os-tee-o-kon-DRY-tis DIS-uh-kanz) is a joint condition in which bone underneath the cartilage of a joint dies due to lack of blood flow. This bone and cartilage can then break loose, causing pain and possibly hindering joint motion.

Osteochondritis dissecans occurs most often in children and adolescents. It can cause symptoms either after an injury to a joint or after several months of activity, especially high-impact activity such as jumping and running, that affects the joint. The condition occurs most commonly in the knee, but also occurs in elbows, ankles and other joints.

Doctors stage osteochondritis dissecans according to the size of the injury, whether the fragment is partially or completely detached, and whether the fragment stays in place. If the loosened piece of cartilage and bone stays in place, you may have few or no symptoms. For young children whose bones are still developing, the injury might heal by itself.

Surgery might be necessary if the fragment comes loose and gets caught between the moving parts of your joint or if you have persistent pain.