Training program and additional electric muscle stimulation for patellofemoral pain syndrome: a pilot study.

Objectives: To 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.

Design: A randomized clinical trial.

Setting: Supervised physiotherapy (PT) training and home-based EMS.

Participants: Patients (N=38; 14 men, 24 women) with bilateral PFPS.

Interventions: One 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 40 Hz, with a pulse duration of .2 6ms, at 5 seconds on and 10 seconds off. Maximal tolerable stimulation intensity was up to 80 mA.

Main Outcome Measures: Patellofemoral 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.

Results: Thirty-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.

Conclusions: A 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.