Constitutional aspects of the osteochondroses.

The osteochondroses comprise a heterogeneous group of clinical disorders, the diagnosis of which is generally confirmed by radiologic appearances. The causes are unknown and little pathologic material has been examined to resolve this problem. Moreover, study of the affected bone yields minimal insight into the cause of the disorder because bone cells respond in a set pattern irrespective of the initial injury. Although acute trauma or prolonged abnormal mechanical forces in the region of epiphysis can lead to bone collapse and necrosis, it is unlikely that such forces are sufficient to affect normal healthy bone. The timing, distribution, multiple sites and familial etiology, as well as the close association between osteochondroses and certain congenital disorders, strongly suggest that there is constitutional epiphyseal inadequacy. The daily stresses of healthy childhood activity are enough to compromise the development of constitutionally weak epiphyses. When architectural bone collapses, the full osteochondrotic picture is manifested. Bone compaction can be brought about only by mechanical means and the force needed is inversely proportional to the degree of epiphyseal abnormality, e.g., a mildly dyschondrotic epiphysis will not present clinically without sufficient trauma to produce architectural collapse. Recent anthropomorphic studies have shown that children with Perthe's disease have a generalized growth disorder. Further long-term comprehensive biological studies are needed to provide more data on children suffering from the osteochondroses if the underlying constitutional defects are to be identified.