|Classification and external resources|
Microscopic view of osteochondritis dissecans in a Danish sow (bar = 200 μm)
Osteochondrosis is a family of orthopedic diseases of the joint that occur in children and adolescents and in rapidly growing animals, particularly pigs, horses, and 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. This disorder is defined as a focal disturbance of endochondral ossification and is regarded as having a multifactorial etiology, so no one thing accounts for all aspects of this disease.
The ultimate cause for these conditions is unknown, but the most commonly cited etiologic factors are rapid growth, heredity, trauma (or overuse), anatomic conformation, and dietary imbalances; however, only anatomic conformation and heredity are well supported by scientific literature. The way that the disease is initiated has been debated. Although failure of chondrocyte differentiation, formation of a fragile cartilage, failure of blood supply to the growth cartilage, and subchondral bone necrosis all have been proposed as the starting point in the pathogenesis, recent literature strongly supports failure of blood supply to growth cartilage as most likely.
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, giving a "hunch-back" appearance.
In humans, these conditions may be classified into three groups:
- Spinal: Scheuermann's disease (of the interspinal joints) which is a curve in the thoracic spine.
- 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 or third metatarsal of the foot and less frequently the first or fourth; sometimes called Freiberg's Infraction or Freiberg's disease)
- Non-articular: This group includes Sever's disease (of the calcaneus, or heel), and Kienbock's disease of the hand, and other conditions not completely characteristic of the osteochondrosis, such as Osgood-Schlatter's disease (of the tibial tubercle) and Osteochondritis dissecans.
The term osteochondrosis has been used to describe a wide range of lesions among different species. There are different types of the prognosis: latens, which is a lesion restricted to epiphyseal cartilage, manifesta, a lesion paired with a delay in endochondral ossification, and dissecans which is a cleft formation in the articular cartilage. 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 cases of osteochondrosis, 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.
- Ytrehus B, Carlson CS, Ekman S (July 2007). "Etiology and pathogenesis of osteochondrosis". Vet. Pathol. 44 (4): 429–48. doi:10.1354/vp.44-4-429. PMID 17606505.
- "osteochondrosis" at Dorland's Medical Dictionary
- Medical College of Wisconsin
- "Bone Scintigraphy in Kienbock's Disease". Retrieved 2008-11-17.
- "Legg-Calvé-Perthes Disease". Retrieved 2008-11-17.
- "Scheuermann's Disease - Orthogate - Improving orthopedic care, education and research with Internet technologies". Retrieved 2008-11-17.
- [C:\WINDOWS\Temporary Internet Files\Content.IE5\OV2L4B0J\osteochondrosis.html "Osteochondrosis / Osteochondritis"]. Retrieved 2008-11-16.
- "Sever’s Disease - The Southern California Orthopedic Institute". Retrieved 2008-11-17.
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