Osteochondritis Dissecans

Abstract

THE observation of several cases of osteochondritis in rather unusual sites is the basis for the résumé of this entity. The first description of this type of loose body was by Franz Koenig, in 1888. When he described the segregation of a portion of cartilaginous and subchondral tissue into the joint space, giving it the name “osteochondritis dissecans,” he suggested that it might be the result of a low grade infectious process. The condition is not unusual—indeed far from rare—as numerous reports of cases are found in the literature, particularly since 1910, when Freiberg and Wooley described the process in the English literature. The most commonly reported sites of the process are in the external condyle of the humerus and the lateral portion of the mesial condyle of the femur, the patella being mentioned in a few cases. It occurs chiefly in males of young adult age, although it has often been noted in young adolescents, particularly by Panner. Although Koenig mentioned several cases of loose bodies in the hip joint and ascribed the etiology to osteochondritis dissecans, Phemister has drawn attention to the fact that in several of these cases the head was detached from the neck near the region of the epiphyseal line and that this is not the site of separation in loose bodies of this classification. As regards the etiology there is considerable diversity of opinion. Although the roentgen examination has afforded a valuable means of observing the development and progress of the lesion, it has not afforded an explanation as to the cause. Barth was one of the earliest writers who regarded the condition, not as the result of a disease named osteochondritis dissecans by Koenig, but as a pathological process definitely the result of trauma. The lack of a definitely traumatic history in many cases and the occasional occurrence of a bilateral case, has inspired a great many theories to explain the characteristic separation of the fragments from a free articular surface. Barth felt that the pull of ligaments at their insertion was a common cause of the condition. Kappis believed that the knee and elbow, due to their anatomical resemblance, were predisposed to a traumatic fissure of the cartilage and this resulted in a lesion of the convex articular surface. Freiberg offers another theory. He believes that the occurrence of a long tubercle on the mesial tibial spine in a position of flexion and external rotation of the tibia or the femur results in a localized trauma to an arteriole in the mesial femoral condyle. Colvin takes a different view and has demonstrated the presence of capillaries in the fibro-cartilage, which have grown after detachment of the fragment. He believes that this indicates a vital process. He believes that the production of fibro-cartilage along the line of cleavage causes the fragment to bulge toward the joint and finally fracture, the thin hyalin plate holding it in place.