Detection of intraarticular abnormalities in osteoarthritis of the knee

Objective. To determine whether intraarticular abnormalities in osteoarthritis (OA) of the knee can be detected as well by needle arthroscopy as by standard arthroscopy. Methods. Needle arthroscopy followed by standard arthroscopy was performed on 10 patients with knee OA (diagnosed according to American College of Rheumatology criteria) whose symptoms were not entirely attributable to the OA and were therefore an indication for further evaluation. Each knee was assessed for abnormalities of the menisci, articular cartilage (6 sites), and synovium (6 sites). Results. Evaluation of the 18 menisci visualized with both techniques yielded the same results: 6 abnormal and 12 normal. Among the 54 articular cartilage sites evaluable with both procedures, 16 were judged normal by both needle arthroscopy and standard arthroscopy. Of the 38 cartilage sites judged abnormal by standard arthroscopy, 34 (89%) were abnormal by needle arthroscopy. Both techniques indicated cartilage changes were the same at 42 (78%) of the 54 sites; changes at the other 12 sites were 1 grade higher by standard arthroscopy than by needle arthroscopy. Both needle arthroscopy and standard arthroscopy revealed 51 evaluable sites in the synovium. Of 34 areas judged abnormal by standard arthroscopy, 24 (71%) were also judged abnormal by needle arthroscopy; 17 areas were judged normal by both techniques. The 2 techniques assigned the same macroscopic score in 27 (53%) of 51 areas of the synovium, with a higher grade by standard arthroscopy in all but 1 of the other 16 areas. Conclusion. These pilot data suggest that in knee OA, needle arthroscopy can 1) accurately detect meniscal abnormalities, 2) detect cartilage abnormalities, but may underestimate the severity, and 3) detect most synovial abnormalities, but often underestimates the severity. Needle arthroscopy is a potentially valuable rheumatologic tool for the assessment of OA of the knee.