With the disease called osteochondritis dissecans, the bone below the cartilage is disturbed. As a result, the affected area can partially or completely separate from the rest of the bone. The bone-cartilage fragment can then be found as a loose body within the knee joint, leaving behind a cartilage-bone defect than can lead to early arthritis and pain.
Osteochondritis dissecans is most likely caused by repetitive microtrauma and decreased bone blood supply. At the early stages, pain can be mild and nonspecific and is usually related to activity.
Osteochondritis dissecans can affect the knee joint, the ankle joint, and even the elbow joint. The knee joint, specifically the area of the medial (inner) part of the femur (thigh bone), is most frequently affected.
Early-stage lesions in young children can heal spontaneously with activity modification and refraining from impact sports and jumping and running sports. In more advanced stages, arthroscopy and retrograde drilling (drilling through the subchondral bone lamina from outside the knee joint) can increase the healing rate and stimulate regeneration: through the holes, vessels and stem cells enter the necrotic area and can thus rebuild the bone.
In cases of partial detachment of the cartilage, arthroscopy and refixation with self-absorbing pins can be necessary. When the cartilage has detached completely, the lesion needs to be stabilized and covered with synthetic tissue or cultivated cartilage tissue.