Electric muscle stimulation of the quadriceps in the treatment of patellofemoral pain

Callaghan MJ, Oldham JA. Electric muscle stimulation of the quadriceps in the treatment of patellofemoral pain. Arch Phys Med Rehabil 2004;85:956-62. Objective To compare a commercially available electric muscle stimulation regimen with a novel form of stimulation for the rehabilitation of the quadriceps muscle, in patients with patellofemoral pain syndrome. Design Double-blinded randomized trial with a parallel control group and stratified randomization. Setting Home-based rehabilitation program assessed in research center. Participants Eighty patients (47 women, 33 men) with patellofemoral pain syndrome. Interventions One group (EMPI) received 1 uniform constant frequency component of 35Hz. The other (EXPER) group received an experimental form of stimulation that contained 5 simultaneously delivered frequency components of 125, 83, 50, 2.5, and 2Hz. Stimulation was applied to the quadriceps muscles of the affected leg for 1 hour daily for 6 weeks, a total of 42 treatments. Main outcome measures Lower-limb isometric and isokinetic torque, quadriceps fatigue, knee flexion, patellar pain, a step test, quadriceps cross-sectional area, and Kujala patellofemoral score for pain before and after treatment. Results Seventy-four patients (43 women, 31 men) completed the trial. Patients in both groups showed significant improvements in all outcomes (P.05) except for quadriceps cross-sectional area (P=.023). Conclusions One form of stimulation was just as efficacious as the other in improving subjective and objective measures. © 2004 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.