New knowledge of osteoarthrosis.

It is being gradually accepted that osteoarthrosis should be regarded in functional terms and, for investigative purposes, as 'joint failure'. Various anatomical, metabolic, and tissue factors can all produce the same end result in the final common pathway of cartilage degeneration, pain, and loss of joint function. Thus osteoarthrosis is a heterogeneous disease that is age-related but is not merely a consequence of ageing. This makes finding a single initial pathogenic mechanism difficult and may imply the coexistence of more than one aetiological factor. There are many reviews of osteoarthrosis (Sokoloff, 1969; Howell and Bollet, 1973; Ali et al., 1974; Kempson et al., 1975; Lee et al., 1974). This brief survey is limited to examining some of the recent concepts and developments in the study of osteoarthrosis and joint failure. Osteoarthrosis has been divided traditionally into primary and secondary forms. We can argue that with sufficient knowledge of the disease we shall be able to describe all osteoarthrosis as secondary to some initiating factor. At present there are varieties which, because we lack knowledge of a cause, we term primary or idiopathic. It is this type of disorder which needs an explanation most urgently. It is noteworthy that some varieties of secondary osteoarthrosis are due to mechanical failure or mechanical misalignment of the joints. In this category we find osteoarthrosis secondary to congenital hip dislocation, Perthes's disease, slipped capital femoral epiphysis, and other forms of osteoarthrosis due to altered geometry of the femoral head, femoral neck, and acetabular interrelationships. We are familiar, too, with some of the endocrine and metabolic influences that cause osteoarthrosis such as acromegaly, chondrocalcinosis, and ochronosis.