Influence of manual therapy on functional mobility after joint injury in a rat model

Abstract

Context: Animal models can be used to investigate manual therapy mechanisms, but testing manipulation in animal models is problematic because animals cannot directly report their pain. Objective: To develop a rat model of inflammatory joint injury to test the efficacy of manual therapy in reducing nociception and restoring function. Methods: The authors induced acute inflammatory joint injury in rats by injecting carrageenan into the ankle and then measured voluntary running wheel activity in treated and untreated rats. Treatments included manual therapy applied to the ankle and knee of the injured limb and several analgesic medications (eg, morphine, ketorolac, prednisone). Results: Intra-articular injection of carrageenan to the ankle produced significant swelling (diameter of the ankle increased by 64% after injection; P=.004) and a robust reduction in voluntary running wheel activity (running distance reduced by 91% compared with controls; P