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BIOMECHANICAL DETERMINANTS OF PATELLOFEMORAL JOINT FORCES by Yu-Jen Chen A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (BIOKINESIOLOGY) August 2008 Copyright 2008 Yu-Jen Chen
|Title||Biomechanical determinants of patellofemoral joint forces|
|Degree||Doctor of Philosophy|
|School||School of Dentistry|
|Advisor (committee chair)||Powers, Christopher M.|
|Advisor (committee member)||
Salem, George J.
Lee, Thay Q.
Azen, Stanley P.
|Abstract||Patellofemoral pain (PFP) is a common disorder of the knee affecting as many as 22% of the general population. A commonly cited theory states that PFP is the result of elevated patellofemoral joint reaction forces (PFJRF 's) which contribute to excessive joint stress and articular cartilage pathology. Although previous investigations have reported decreased PFJRF' s in the PFP population, these studies have been limited by two-dimensional modeling approaches. The primary objectives of this dissertation was to determine if persons with PFP demonstrate differences in PFJRF' s compared to pain-free controls, and to identify the factors that contribute to altered forces in this population. To address this aim, three studies were undertaken. The purpose of Chapter III was to develop a three-dimensional, subject-specific model of the patellofemoral joint and to test this model in a group of healthy individuals. Results revealed that estimates of the magnitude and direction of the PFJRF could be obtained during dynamic activities and that PFJRF 's varied significantly based on the task performed. The purpose of Chapter IV was to determine if persons with PFP exhibit differences in PFJRF 's compared to healthy individuals. It was determined that persons with PFP demonstrated lower peak resultant PFJRF s when compared to pain-free controls. Individuals with PFP also demonstrated lower peak posterior and superior forces, however higher peak lateral forces were observed in three out of four activities evaluated.; The purpose of Chapter V was to further evaluate the findings of Chapter IV by determining the contributors to the increased lateral forces in the PFP group. Data revealed that both structural and dynamic factors contributed to the functional Q-angle in persons with PFP with the largest contributors being frontal and transverse plane knee kinematics. Overall, the results of this dissertation demonstrate that subject-specific, three-dimensional PFJRF's can be quantified using an image-based model. Contrary to previous assumptions, persons with PFP do not demonstrate increased patellofemoral joint compressive forces, however these individuals exhibit increased lateral forces acting on the patella. The finding of increased lateral patella forces in persons with PFP may explain the clinical observations of lateral patella subluxation in this population.|
|Keyword||PFJRF; patellofemoral pain; modeling|
|Part of collection||University of Southern California dissertations and theses|
|Publisher (of the original version)||University of Southern California|
|Place of publication (of the original version)||Los Angeles, California|
|Publisher (of the digital version)||University of Southern California. Libraries|
|Legacy record ID||usctheses-m1377|
|Repository name||Libraries, University of Southern California|
|Repository address||Los Angeles, California|
|Full text||BIOMECHANICAL DETERMINANTS OF PATELLOFEMORAL JOINT FORCES by Yu-Jen Chen A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (BIOKINESIOLOGY) August 2008 Copyright 2008 Yu-Jen Chen|