The osteochondroses. A new pathological concept.

In all histopathological studies of the osteochondroses, the one constant finding is a dysplastic change in the cartilaginous epiphysis and apophysis. This gives rise to disturbances of enchondral ossification, diminished mechanical resistance of the abnormal cartilage, and to ischaemic changes in the ossific nucleus. This has been demonstrated histologically only in Perthes disease and Köhler's disease and probably reflects vascular damage provoked by abnormal cartilaginous growth. Cartilage dysplasia could constitute the fundamental pathogenetic background common to all the osteochondroses.