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9
Figure 2-1. The normal Q-angle (a) results in a laterally directed force on the patella.
Femoral internal rotation (b), and femoral adduction (c), can increase
the Q-angle.
In-vitro studies support the concept of abnormal lower extremity motions as
being contributory to patellofemoral joint dysfunction. For example, Lee et al.44
reported that femoral internal rotation significantly increased lateral facet pressures
in a cadaver model. Furthermore, Huberti and Hayes33 demonstrated that a 10 degree
change in the Q-angle resulted in 45% increase in patellofemoral joint stress.
Although abnormal lower extremity kinematics have been implicated as
being contributory to patellofemoral joint dysfunction, in-vivo evidence in this area
is lacking. Chapter III of this dissertation sought to determine whether persons with
PFP exhibit altered hip kinematics that may be contributory to patellofemoral joint
dysfunction. Identification of such movement patterns is an important step in
designing effective treatment and prevention strategies. Furthermore, an
16° 24° 24°
a b c
Object Description
| Title | The influence of hip and femur kinematics on patellofemoral joint dysfunction |
| Author | Souza, Richard B. |
| Author email | rsouza@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Biokinesiology & Physical Therapy |
| School | School of Dentistry |
| Date defended/completed | 2008-03-13 |
| Date submitted | 2008 |
| Restricted until | Unrestricted |
| Date published | 2008-04-01 |
| Advisor (committee chair) | Powers, Christopher M. |
| Advisor (committee member) |
Keim, Robert G. Kulig, Kornelia Salsich, Gretchen |
| Abstract | Recent research suggests that altered patellofemoral joint mechanics may be the result of femur motion as opposed to patella motion. The purpose of this dissertation was to clearly define the role of hip/femur motion in contributing to patellofemoral joint dysfunction. To accomplish this objective, three studies were undertaken.; The purpose of study #1 was to determine whether individuals with patellofemoral pain (PFP) demonstrate abnormal hip kinematics during functional tasks and to determine if such motions could be explained by hip muscle weakness and/or abnormal muscle activation patterns. Results revealed that PFP subjects demonstrated increased hip internal rotation, hip muscle weakness, and increased gluteus maximus EMG when compared to pain-free controls. These findings suggest that subjects with PFP were attempting to recruit a weakened muscle, perhaps in an effort to stabilize the hip joint.; The purpose of study #2 was to determine if hip muscle performance and femoral morphology differ between females with PFP and pain-free controls, and to determine to what degree these measures predict hip internal rotation during running. Females with PFP demonstrated deficits in eight of ten hip strength measurements and increased femoral inclination. Step-wise regression analysis revealed that isotonic hip extension endurance was the only predictor of hip internal rotation.; The purpose of study #3 was to determine if individuals with PFP demonstrate excessive medial femoral rotation and to determine whether femur motion contributes to altered patellofemoral joint kinematics (as opposed to patella motion). Findings revealed that females with PFP demonstrated greater lateral patella displacement & tilt and medial femoral rotation, with no differences in patella rotation. Based on these results it was concluded that altered patellofemoral joint kinematics in persons with PFP appears to be more related to excessive medial femoral rotation as opposed to lateral patella rotation.; A common finding across all studies was the observation of increased internal rotation of the hip/femur in females with PFP. The tendency for the hip to internally rotate was associated with diminished hip muscle performance as opposed to femoral structure. Taken together, these studies suggest that the etiology of patellofemoral joint dysfunction may have a proximal origin. |
| Keyword | biomechanics; magnetic resonance imaging; motion analysis |
| Language | English |
| 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 |
| Type | texts |
| Legacy record ID | usctheses-m1065 |
| Contributing entity | University of Southern California |
| Rights | Souza, Richard B. |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@dots.usc.edu |
| Filename | etd-Souza-20080401 |
| Archival file | uscthesesreloadpub_Volume26/etd-Souza-20080401.pdf |
Description
| Title | Page 21 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | 9 Figure 2-1. The normal Q-angle (a) results in a laterally directed force on the patella. Femoral internal rotation (b), and femoral adduction (c), can increase the Q-angle. In-vitro studies support the concept of abnormal lower extremity motions as being contributory to patellofemoral joint dysfunction. For example, Lee et al.44 reported that femoral internal rotation significantly increased lateral facet pressures in a cadaver model. Furthermore, Huberti and Hayes33 demonstrated that a 10 degree change in the Q-angle resulted in 45% increase in patellofemoral joint stress. Although abnormal lower extremity kinematics have been implicated as being contributory to patellofemoral joint dysfunction, in-vivo evidence in this area is lacking. Chapter III of this dissertation sought to determine whether persons with PFP exhibit altered hip kinematics that may be contributory to patellofemoral joint dysfunction. Identification of such movement patterns is an important step in designing effective treatment and prevention strategies. Furthermore, an 16° 24° 24° a b c |
