PAINFUL SNAPPING IN RHEUMATOID KNEES

Painful snapping caused by a solitary intra-articular nodular mass was found in 11 knee joints of 8 patients with rheumatoid arthritis, The masses were characteristically situated in the anterolateral aspect of the lateral femoral condyle of each joint, and appeared to jump and s lip in and out of the patellofemoral articulation during flexion and e xtension, The snapping caused by the solitary mass was noticed as the joint flexed from 15 degrees to 30 degrees in 9 knees and from 50 degr ees to 60 degrees in 3. Histopathological examination of the masses re vealed typical findings of a rheumatoid nodule in 4 knee joints and my xomatous degeneration and collagen necrosis in 7.