The therapeutic role of motor imagery during the chronic phase after total knee arthroplasty: a pilot randomized controlled trial.

BACKGROUND: There is now ample evidence that motor imagery contributes to enhance motor learning and promote motor recovery in patients with motor disorders. Whether motor imagery practice is likely to facilitate mobility in patients suffering from knee osteoarthritis, at 6-months after total knee arthroplasty, remains unknown. AIM: This trial was designed to evaluate the therapeutic effectiveness of implementing motor imagery into the classical course of physical therapy at 6-months after total knee arthroplasty. DESIGN: Randomized controlled trial. POPULATION: Twenty-four patients with unilateral total knee arthroplasty were assigned to a motor imagery or control group in a test-retest procedure, following a rehabilitation program as outpatients. METHODS: During both the pre- and post-test, a set of strength and functional mobility measures were assessed: quadriceps strength, peak knee flexion during the swing phase, performance at the timed up and go test, stair climbing test, and 6-minute walk test, and finally Oxford knee score. In addition to a common physical therapy program, the motor imagery group practiced additional motor imagery exercises, while participants of the control group were subjected to a period of neutral activities for an equivalent amount of time. RESULTS: Data provided evidence that motor imagery enhanced the quadriceps muscle strength of the operated knee (F (1, 22)=10.36, P=0.003), improved the peak knee flexion during the swing phase (F (1, 22)=31.52, P<0.001), and increased the speed to climb and descend stairs (F (1, 22)=14.28, P=0.001). CONCLUSIONS: This study demonstrated the effectiveness of motor imagery exercises in gait performance and functional recovery in a small sample of individuals who underwent total knee arthroplasty. However, before drawing final conclusions sample size calculation should be conducted in the future. CLINICAL REHABILITATION IMPACT: While waiting for further research, our findings encourage incorporating motor imagery exercises into classical physical therapy protocols at 6-months after total knee arthroplasty.