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7
the patella moving on the femur; however such studies were performed in a non-weight-
bearing condition where femoral motion was constrained.51,52 Recent
research suggests that patellofemoral joint kinematics may be different during
weight-bearing movments.72 Using dynamic MRI methods under weight-bearing
conditions (a single leg partial squat), Powers et al.72 demonstrated that the primary
contributor to lateral patellar tilt in a small group of individuals with patellar
instability (n=6) was femoral motion (internal rotation) and not patellar motion. This
finding calls into question the long-held assumption that patellar subluxation is the
result of the patella moving on the femur. While this may be the case during non-weight-
bearing activities in which the femur is fixed (i.e. during knee extension in
sitting), the results of Powers et al.72 provide evidence that subluxation of the patella
during weight-bearing activities may be the result of the femur rotating underneath
the patella. Chapter V of this dissertation expands existing work in this area by
defining the role of femoral rotation in contributing to abnormal patellofemoral
kinematics.
CAN ABNORMAL HIP KINEMATICS CONTRIBUTE TO PATELLO-FEMORAL
JOINT DYSFUNCTION?
The natural tendency of the patella to track laterally has been described by
Fulkerson and Hungerford20 as the "law of valgus". As the quadriceps follows the
longitudinal axis of the femur, the quadriceps angle (Q-angle) is formed, creating a
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 |
| Advisor (committee member) |
Keim, Robert 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 | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Souza-20080401 |
| Archival file | uscthesesreloadpub_Volume26/etd-Souza-20080401.pdf |
Description
| Title | Page 19 |
| Contributing entity | University of Southern California |
| Full text | 7 the patella moving on the femur; however such studies were performed in a non-weight- bearing condition where femoral motion was constrained.51,52 Recent research suggests that patellofemoral joint kinematics may be different during weight-bearing movments.72 Using dynamic MRI methods under weight-bearing conditions (a single leg partial squat), Powers et al.72 demonstrated that the primary contributor to lateral patellar tilt in a small group of individuals with patellar instability (n=6) was femoral motion (internal rotation) and not patellar motion. This finding calls into question the long-held assumption that patellar subluxation is the result of the patella moving on the femur. While this may be the case during non-weight- bearing activities in which the femur is fixed (i.e. during knee extension in sitting), the results of Powers et al.72 provide evidence that subluxation of the patella during weight-bearing activities may be the result of the femur rotating underneath the patella. Chapter V of this dissertation expands existing work in this area by defining the role of femoral rotation in contributing to abnormal patellofemoral kinematics. CAN ABNORMAL HIP KINEMATICS CONTRIBUTE TO PATELLO-FEMORAL JOINT DYSFUNCTION? The natural tendency of the patella to track laterally has been described by Fulkerson and Hungerford20 as the "law of valgus". As the quadriceps follows the longitudinal axis of the femur, the quadriceps angle (Q-angle) is formed, creating a |
