Correlative histologic and arthroscopic evaluation in rheumatoid knee joints. 
The correlation between arthroscopic observations and histologic changes in rheumatoid arthritis is still controversial.  Synovial samples of 21 knee joints in rheumatoid arthritis patients were comparatively investigated by endoscopy and histology.  Biopsies were scored by an endoscopist and subsequently dissected.  Different histochemical and immunocytochemical staining techniques were used to define inflammatory activity.  Arthroscopic and histological values were compared by rating scales and variance analysis.  Our study indicates that synovial biopsy is of diagnostic value in rheumatoid arthritis.  However, its usefulness depends on the histochemical methods used.  The results revealed highly significant correlations of endoscopic features with the number of neutrophilic granulocytes, intravascular leukocytes, and peroxidase-positive macrophages.  However, no relationship was found between the detection of lymphocytes or resident macrophages and inflammatory scores.  The close correlation between endoscopic and histological findings suggests that arthroscopic evaluation allows a valuable classification of the inflammatory activity in rheumatoid synovitis.