The effect of a single treatment of the Protonics™ system on lower extremity kinematics during gait and the lateral step up exercise

Introduction Patellofemoral pain (PFP) is often attributed to abnormal patellar tracking. The Protonics™ knee orthosis was developed to reduce femoral internal rotation by altering pelvic alignment via hamstring activation. The purpose of this research was to determine if a single treatment with the orthosis improved lower extremity alignment during gait and the lateral step up exercise. We hypothesized that anterior pelvic tilt, hip internal rotation and adduction, and external rotation of the tibia with respect to the femur would decrease after use of the brace. Methods Nineteen females (23.4 ± 3.1 year, 1.66 ± 0.05 m, 65.3 ± 20.4 kg) with chronic PFP participated. Three-dimensional kinematic data were collected for each subject at 60 Hz during pre-treatment (PRE), after a placebo condition with the orthosis set at zero resistance (PLAC), and post-treatment (POST). Treatment consisted of having the subject perform the rehabilitation exercises recommended by the Protonics™ manufacturer. A repeated measures ANOVA was performed on each dependent variable (α = 0.05). Results This investigation did not verify the changes in alignment proposed by the manufacturer as a result of acute application of the Protonics™ system. However, after the use of the brace, pelvic rotation and hip hike were decreased during the lateral step up exercise. Conclusion Based on the results of this study, it was concluded that a single application of the Protonics™ system did not alter anterior pelvic tilt, hip internal rotation and adduction, or tibial external rotation during the lateral step up and gait.