Osteochondrosis

Overview
The Osteochondroses are a family of orthopedic diseases that occur in children and in rapidly growing animals, particularly pigs, horses, and large breed dogs. They are characterized by interruption of the blood supply of a bone, in particular to the epiphysis, followed by localized bony necrosis and later, regrowth of the bone.

Cause
The ultimate cause for these conditions is unknown, although several of the human osteochrondroses are more common in very active individuals. This leads some researchers to speculate that cumulative microtrauma may be the primary event. Osteochondrosis in swine has been shown to be a condition responsive to supplementation with the essential trace element boron and may be a manifestation of boron deficiency.

Presentation
These conditions nearly all present with an insidious onset of pain referred to the location of the bony damage. Some, notably Kienbock's disease of the wrist, may involve considerable swelling, and Legg-Calvé-Perthes disease of the hip causes the victim to limp. The spinal form, Scheuermann's disease, may cause bending, or kyphosis of the upper spine.

Human osteochondroses
In humans, these conditions may be classified into three groups:
 * 1. Spinal: Scheuermann's disease (of the interspinal joints)
 * 2. Articular: Legg-Calvé-Perthes disease (or, avascular necrosis of the femoral head in the hip), Köhler's disease (of the tarsal navicular bone of the foot), Panner's disease (of the capitulum of the elbow), and Freiberg's infraction (of the second metatarsal of the foot; sometimes called Freiberg's Infarction or Freiberg's disease)
 * 3. Non-articular: This group includes Kienbock's disease (of the lunate bone of the wrist) and Sever's disease (of the calcaneus, or heel), and other conditions not completely characteristic of the osteochondroses, such as Osgood-Schlatter's disease (of the tibial tubercle) and Osteochondritis dissecans.

Prognosis
The prognosis for these conditions is very variable, and depends both on the anatomic site and on the time at which it is detected. In some osteochondroses, such as Sever's disease and Freiberg's infraction, the involved bone may heal in a relatively normal shape and leave the patient asymptomatic. On the contrary, Legg-Calvé-Perthes disease frequently results in a deformed femoral head that leads to arthritis and the need for joint replacement. Surgery to correct this problem is long, and can be very painful.