Connective tissue response to immobility. Correlative study of biomechanical and biochemical measurements of normal and immobilized rabbit knees.

The biomechanical changes in rabbit knee contractures were measured after 9 weeks of immobilization. These results were correlated with the biochemical composition of periarticular connective knee tissue of the same knees. The loss of total hexosamine correlates significantly with joint stiffness on an animal-to-animal basis. Total hexosamine also correlates with the energy required cyclicly to flex and to extend the experimental joints. Of the individual glycosaminoglycan fractions, only hyaluronic acid showed significant correlation with the biomechanical data. The possible mechanism of contracture formation was postulated based on these results.