A comparison of two types of electrical stimulation of the quadriceps in the treatment of patellofemoral pain syndrome. A pilot study

Objective: To compare a commercially available electrical muscle stimulation regime with a new form of stimulation for the rehabilitation of the quadriceps in patients with patellofemoral pain syndrome. Setting: A research facility within a teaching hospital. Methods: Sixteen patients (four men, 12 women) with patellofemoral pain, demonstrable quadriceps atrophy, but normal gait parameters were randomly allocated to one of two treatment groups. One group received a sequential mixed frequency stimulation pattern from a standard device. The other group received a new form of stimulation from an experimental stimulation device that contained simultaneous mixed frequency components. Outcome measures: Isometric and isokinetic extension torque, muscle fatigue rate, pain, functional questionnaire, step test, knee flexion, and quadriceps cross-sectional area. Results: These showed significant improvements for both groups after treatment (p < 0.05) in all outcome measures except flexion and fatigue rates, but no significant differences between the two stimulation regimes (p > 0.05). Conclusion: Both stimulators performed similarly on patients with patellofemoral pain giving significant improvements for all patients for muscle strength, pain, self-reporting function and step testing. There were no significant differences between the two types of stimulation.