Synovial fluid collagenase in patients with destructive arthritis of the shoulder joint

We studied synovial fluid (SF) collagenase in 10 women with severe rheumatoid arthritis (RA), 10 with pyrophosphate arthropathy, and 10 with idiopathic destructive disease of the shoulder conforming to a pattern recently described. SF cell counts were highest in the RA group. Particles were detected by polarized light microscopy and alizarin red staining. Crystals were seen in fluids from all 3 groups; pyrophosphate predominated in the pyrophosphate arthropathy group and alizarin red-positive particles in the idiopathic disease group. Collagenase and tissue inhibitor of metalloproteinase levels were estimated in SF after gel filtration. Tissue inhibitor of metalloproteinase activity was detected in all fluids, but tended to be highest in the RA group. Collagenase activity was detected in 3 RA fluids only. In no sample was collagenase found in an active form. These findings support the clinical concept of an aggressive destructive process which sometimes occurs in the shoulder joints of elderly women. Because we were not able to detect free collagenase in SF from any of the patients with idiopathic shoulder disease, the data suggest that high levels of active collagenase are not characteristic of this group of patients.