Mechanical and histological studies of acute joint hemorrhage.

In this study, a simple animal model has been used to gather data on the mechanical and histologic changes in cartilage and the histologic changes in synovium attendant to acute joint hemorrhage. The continuous presence of autologous blood in the experimental joints for 10 days results in cartilage which is significantly more compliant than normal. These changes are attributed to loss of proteoglycan. Further, the study demonstrates a consistent pathology of the synovial tissues. Elaboration of degenerative enzymes from iron-laden synovial or subsynovial macrophages must be considered a primary mechanism of cartilage damage.