Powers CM, Ward SR, Chen Y, Chan L, Terk MR; Dept. of Biokinesiology & Physical Therapy and Dept. Radiology, University of Southern California., Los Angeles, CA.

PURPOSE: To test the hypothesis that individuals who respond favorably to patellar bracing will exhibit decreased patellofemoral joint stress during stair ambulation. SUBJECTS: Fifteen subjects (ranging in age from 18 to 45) with a diagnosis of patellofemoral pain participated. Subjects were included if they reported pain reduction following application of a patellofemoral brace (On-Track, Don Joy Inc.) METHODS: All subjects competed two phases of data collection. Phase one consisted of MRI assessment to determine patellofemoral joint contact area, while phase two consisted of kinematic and kinetic analysis of stair ascent and stair descent. Data obtained from both data collection sessions were required as input variables into a biomechanical model to quantify patellofemoral joint stress. ANALYSIS: Peak patellofemoral joint reaction force, average utilized contact area, and peak patellofemoral joint stress were compared between brace conditions using separate two-way ANOVA’s with repeated measures (brace condition x stair condition). RESULTS: Although subjects reported an average decrease in pain of 56%, there was no difference in peak stress between braced and non-braced conditions during stair ascent or descent. This finding can be explained by the fact that despite improvements in contact area, bracing resulted in greater knee extensor moments and joint reaction forces under both conditions. CONCLUSIONS:. Our results do not support the hypothesis that individuals with patellofemoral pain would demonstrate reduced patellofemoral stress during stair ambulation following the application of a patellar brace. RELEVANCE: Although bracing did not decrease patellofemoral joint stress during stair ascent and descent, the increase in quadriceps utilization and tolerance of joint reaction forces would appear to be beneficial consequences of bracing. FUNDING SOURCE: Don Joy Orthopaedics Inc.

Copyright 2003 by the American Physical Therapy Association

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