Study design: Randomized clinical trial.
Objectives: To investigate the clinical efficacy of the addition of the Protonics system to a standard exercise-based patellofemoral rehabilitation protocol.
Background: The Protonics system has been suggested as an intervention for patients with patellofemoral pain syndrome (PFPS). However, the effects of this system have not been compared to the effects associated with traditional exercise-based rehabilitation alone.
Methods and measures: Seventeen of 34 females (mean age, 28 years; range, 13-55 years) diagnosed with PFPS were randomly assigned to wear the Protonics system while participating in a conventional exercise-based rehabilitation program. Functional and patient-reported outcome measures were evaluated, including Kujala score and the lateral step-up test. In addition, measurements of hip internal and external rotation, hip extension, and iliotibial band muscle length were compared between groups.
Results: Patients in both groups demonstrated improvement in Kujala score (P<.001), performance on the lateral step-up test (P<.001), and pain during the step-up test (P<.001) at the conclusion of the study. However, there was no difference between groups with respect to improvement in Kujala score (P = .33), step-up test performance (P = .47), or pain during the step-up test (P = .24). Patients using the Protonics system demonstrated greater gain in passive hip extension (P = .023) and increased hip external rotation motion (P = .017) at discharge versus patients treated with exercise alone. However, there was no difference in iliotibial band flexibility (P = .80) or hip internal rotation motion (P = .09) between groups. A greater proportion of patients in the Protonics group reported no pain with step-up testing at each 2-week interval. However, the 2.2 fewer visits required by patients in the Protonics group to meet discharge criteria did not achieve statistical significance (P = .08).
Conclusions: Patients using the Protonics system demonstrated a shift in available hip rotation and increased passive hip extension flexibility. However, these changes were not outside the bounds of potential measurement error and did not translate into significant functional differences from a similar group treated with exercise alone. The economic implications of an average 2.2-visit decrease in treatment sessions per patient using the Protonics system are uncertain.