Scanning electron microscopic studies of extensor tendon degeneration in rheumatoid arthritis

Examination of the surfaces of four normal and six rheumatoid tendons in the hand by scanning electron microscopy clearly showed the processes of degeneration affecting the tendons in rheumatoid arthritis. These findings seemed to correspond to the clinical state. The surfaces of the healthy tendons displayed fine networks of closely enmeshed collagen fibrils and parallel arrangements of collagen bundles. In acute rheumatoid tenosynovitis numerous inflammatory cells were found on the surfaces of the tendons, later crater and groove formations followed, as was observed in degenerated tendons and ruptured stumps in cases in which the active stage already had calmed down. The hypothesis is discussed that disorganization of tendons in rheumatoid disease may be caused by lysosomal enzymes present in greater concentration in the synovial fluid components of rheumatoid patients than in healthy subjects.