Patellar pain and quadriceps rehabilitation: An EMG study

Eighteen patients (26 knees) giving a history of patel lar dislocation and/or subluxation and continued pa tellar symptoms underwent evaluation to determine the efficacy of their rehabilitation programs. Four- channel cine-electromyography was utilized to assess the relative muscular effort of the vastus medialis, vastus lateralis, vastus medialis obliquus, and rectus femoris in a series of exercises. Ten degress of flexion of the knee reduced effective muscle effort in the vasti group to an average of ¼ of the muscle effort dem onstrated in full extension of the knee. No consistent pattern was noted by altering the rotation of the hip from neutral to external or internal rotation. The ad dition of weight (5 Ib) to the ankle did not enhance the muscle effort with the knee in full extension. Quad- sets and straight leg-raising exercises in full knee extension offer the best quadriceps rehabilitation pro gram in the patient with a patellar malalignment syn drome and persistent symptoms.