The effect of bracing on patellofemoral joint stress during free and fast walking.
BACKGROUND
Although several studies have demonstrated decreases in patellofemoral pain (PFP) with the application of bracing, the mechanism by which bracing reduces symptoms has not been elucidated.


OBJECTIVE
Individuals who responded favorably to bracing will exhibit decreased patellofemoral stress during level walking.


METHODS
Repeated measures, cross-sectional.


METHODS
Fifteen subjects with a diagnosis of PFP completed two phases of data collection: 1) MRI assessment of patellofemoral contact area and 2) gait analysis. Data were obtained under braced and nonbraced conditions. Variables obtained from both data collection sessions were used as input variables into a mathematical model to quantify patellofemoral stress.


RESULTS
Subjects reported a 56% reduction in pain following bracing. Bracing significantly reduced peak stress during free and fast walking (17% and 27%, respectively). The decrease in stress was the result of increased contact area as patellofemoral joint reaction forces were increased following bracing.


CONCLUSIONS
Bracing resulted in a larger increase in patellofemoral contact area than the increase in joint reaction force, resulting in a decrease in joint stress.


CONCLUSIONS
The results of this study suggest a possible mechanism by which bracing may be effective in reducing PFP and provides experimental support for the use of this treatment method.
Powers
Christopher M
CM
Department of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California 90089-9006, USA.
Ward
Samuel R
SR
Chen
Yu-jen
YJ
Chan
Li-der
LD
Terk
Michael R
MR
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D001915:Braces; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000503:physiopathology; D005684:Gait / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D010147:Pain Measurement; D010329:Patella / Q000503:physiopathology; D016138:Walking / Q000502:physiology*