Abstract
The rate of elimination of Na131I from the knee joint was measured in 16 patients with bilateral degenerative changes and with pronounced pain on one side only. The elimination was significantly faster on the painful side. Similarly in 11 patients with painful degenerative changes after a previous fracture of the tibial condyle, the elimination of the radioisotope from the affected knee was faster than from the unaffected contralateral side. No difference in the rate of elimination was found between the two sides in 23 patients with similar but painless joint changes. The difference was believed to be due to synovitis in the painful joints.