Training Program and Additional Electric Muscle Stimulation for Patellofemoral Pain Syndrome: A Pilot Study

Bily W, Trimmel L, Mödlin M, Kaider A, Kern H. Training program and additional electric muscle stimulation for patellofemoral pain syndrome: a pilot study.ObjectivesTo evaluate the beneficial effect of training in patients with patellofemoral pain syndrome (PFPS) and influence of additional electric muscle stimulation (EMS) of the knee extensor muscles.DesignA randomized clinical trial.SettingSupervised physiotherapy (PT) training and home-based EMS.ParticipantsPatients (N=38; 14 men, 24 women) with bilateral PFPS.InterventionsOne group (PT) received supervised PT training for 12 weeks. The other received PT and EMS. The stimulation protocol was applied to the knee extensors for 20 minutes, 2 times daily, 5 times a week for 12 weeks at 40Hz, with a pulse duration of .26ms, at 5 seconds on and 10 seconds off. Maximal tolerable stimulation intensity was up to 80mA.Main Outcome MeasuresPatellofemoral pain assessment with visual analog scale during activities of daily life, Kujala patellofemoral score, and isometric strength measurement before and after 12 weeks treatment as well as after 1 year.ResultsThirty-six patients completed the 12-week follow-up. There was a statistically significant reduction of pain in both groups (PT group, P=.003; PT and EMS group, P<.001) and significant improvement of the Kujala score in both groups (PT group, P<.001; PT and EMS group, P<.001) after 12 weeks of treatment with improvement of function and reduction of pain at the 1-year follow-up. The difference between the 2 treatment groups was statistically not significant. We could not measure any significant change in isometric knee extensor strength in either group.ConclusionsA supervised PT program can reduce pain and improve function in patients with PFPS. We did not detect a significant additional effect of EMS with the protocol described previously.