Mechanical conditioning of articular cartilage to prevalent stresses.

The possible correlation between joint stresses and cartilage compressive modulus is examined. The stresses acting upon different areas of the joints and cartilage compressive modulus in these areas were obtained for 15 pairs of ipsilateral human ankle and knee autopsy joint specimens. It was found that the cartilage compressive modulus was significantly correlated with the mechanical stress (r = 0.889 at P < 0.02 level of significance) in such a manner that cartilage subjected to higher predominant stresses was significantly stiffer than that subjected to lower predominant stresses. This was true when comparing ankle with knee joints, and also when comparing different regions within one single joint. Such a correlation is significant in that it indicates that cartilage may well be conditioned mechanically by the prevalent stress it is subject to. However, this correlation of data obtained from autopsy specimens is a necessary, but not sufficient condition, for the above hypothesis to be true. It is, therefore, concluded that further work on animals is necessary.