[Arthroscopic findings of the rheumatoid knee mode of cartilage changes and synovial proliferation in contrast to plain X-ray findings].

To establish a more objective evaluation of the arthroscopic findings in knees affected by rheumatoid arthritis (RA), the degrees of synovial proliferation and cartilage change were classified semiquantitatively. In 73 knees out of 41 cases with RA, the joint surface was divided into 6 regions. The cartilage changes and synovial proliferation at each region was classified into 5 ranks. Plain X-ray findings were evaluated by Larsen's grading system. The cartilage changes found by arthroscopy were more advanced than expected from the radiographical findings. Also, plain radiographical films did not accurately show the degree of synovial proliferation. In cases with Larsen grade III or below, the lateral compartment of the knee, in particular, the lateral meniscus often demonstrated advanced cartilage changes. In cases with Larsen grade IV or above, cartilage loss was uniformly noted in all 6 regions. Advanced cartilage changes were found mostly medially in knees with genu varum and laterally in knees with genu valgum, and were related to the femoro-tibial angle. Advanced synovial proliferation was mostly seen in the lateral gutter regions and the periphery of the menisci regardless of alignment.