Correlation and agreement between the diagnostic results of arthroscopic and histological examinations of the synovial membrane in rheumatoid synovitis of the knee joint have been discussed in small number of studies with contradictory conclusions.
The aim of the present study was to determine the correlation between the arthroscopic characteristics and histology of the synovial membrane in patients with rheumatoid arthritis and synovitis of the knee joint.
Sixty-four arthroscopies of the knee joint with guided multiple synovial biopsies were performed in patients with rheumatoid synovitis. Biopsy samples were taken under visual control from the evidently inflamed synovia in four regions of the knee joint. Arthroscopic assessment of the rheumatoid synovitis was done according the standard system of ACR including 6 criteria. The histological assessment of the synovitis met the EULAR criteria including 6 morphological variables.
High positive correlation (r = +0.76) was established between the arthroscopic and histological assessment of the rheumatoid synovitis in the examined patients. High values were also found for the k coefficient for agreement (k = 0.70). The mean value of synovitis extent according to VAS was 43.16 mm and the mean value of intensity of the inflammatory process according to VAS was 54.31 mm.
The agreement between the arthroscopic and histological diagnosis of the synovitis is in the range of high but not absolute correlation. The two methods are not contradictory and should be used concurrently in patients with chronic rheumatoid synovitis.