Passive range of motion, not isometric exercise, amplifies acute urate synovitis.

The effects of passive range-of-motion and isometric exercises on acute monosodium urate-induced experimental arthritis in a rabbit model were assessed by serial intra-articular temperature measurements and synovial leukocyte counts. Passive range of motion significantly (p less than 0.05) increased both the intra-articular temperature and the synovial leukocyte count over the control values of the nonexercised joints. Isometric exercises across a joint with acute monosodium urate synovitis, however, did not significantly affect intra-articular temperature or synovial leukocyte count.