Objective: To devise and use a method for assessing the effect of dynamic exercise on synovial blood flow in knees with effusions.
Methods: The clearance rate of intraarticular 99mTc-DTPA (diethylene triamine pentaacetic acid) was continuously monitored by a gamma camera during periods of rest or flexion. The rate of 99mTc-DTPA disappearance during a fixed period of exercise which was interposed between 2 rest periods was estimated by extrapolation between the clearance curves for the 2 rest periods.
Results: Cycling and walking increased the clearance rate, straight leg raising had no effect, and flexion decreased the clearance rate.
Conclusion: Our results suggest that some dynamic exercises can increase the rate of synovial blood flow in joints with effusions. This outcome may be beneficial in inflamed joints which are chronically hypoxic due to elevated intraarticular pressure and consequent chronic synovial ischemia.