In vivo patellar tracking induced by individual quadriceps components in individuals with patellofemoral pain

Lin, Fang; Wilson, Nicole A.; Makhsous, Mohsen; Press, Joel M.; Koh, Jason L.; Nuber, Gordon W.; Zhang, Li-Qun

doi:10.1016/j.jbiomech.2009.08.043

« Previous Next »Journal of Biomechanics
Volume 43, Issue 2 , Pages 235-241, 19 January 2010

In vivo patellar tracking induced by individual quadriceps components in individuals with patellofemoral pain

Fang Lin
- Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA
- Northwestern University Department of Physical Medicine and Rehabilitation, 345 East Superior Street, Suite 1406, Chicago, IL 60611, USA
Nicole A. Wilson
- Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA
- Illinois Institute of Technology, Department of Biomedical Engineering, Engineering 1 Bldg, 10 West 32nd Street, Chicago, IL 60616, USA
Mohsen Makhsous
- Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA
- Northwestern University Department of Physical Medicine and Rehabilitation, 345 East Superior Street, Suite 1406, Chicago, IL 60611, USA
Joel M. Press
- Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA
- Northwestern University Department of Physical Medicine and Rehabilitation, 345 East Superior Street, Suite 1406, Chicago, IL 60611, USA
Jason L. Koh
- Northwestern University, Department of Orthopaedic Surgery, 645 North Michigan Avenue, Suite 910 Chicago, IL 60611, USA
Gordon W. Nuber
- Northwestern University, Department of Orthopaedic Surgery, 645 North Michigan Avenue, Suite 910 Chicago, IL 60611, USA
Li-Qun Zhang
- Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA
- Northwestern University Department of Physical Medicine and Rehabilitation, 345 East Superior Street, Suite 1406, Chicago, IL 60611, USA
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, IL 60208-3107, USA
- Northwestern University, Department of Orthopaedic Surgery, 645 North Michigan Avenue, Suite 910 Chicago, IL 60611, USA
- Corresponding author at: Rehabilitation Institute of Chicago, Sensory Motor Performance Program, 345 East Superior Street, Room 1408, Chicago, IL 60611, USA. Tel.: +13122384767; fax: +13122382208.

Accepted 28 August 2009. published online 30 October 2009.

Abstract

Patellofemoral pain is a common knee disorder with a multi-factorial etiology related to abnormal patellar tracking. Our hypothesis was that the pattern of three-dimensional rotation and translation of the patella induced by selective activation of individual quadriceps components would differ between subjects with patellofemoral pain and healthy subjects. Nine female subjects with patellofemoral pain and seven healthy female subjects underwent electrical stimulation to selectively activate individual quadriceps components (vastus medialis obliquus, VMO; vastus medialis lateralis, VML; vastus lateralis, VL) with the knee at 0° and 20° flexion, while three-dimensional patellar tracking was recorded. Normalized direction of rotation and direction of translation characterized the relative amplitudes of each component of patellar movement. VMO activation in patellofemoral pain caused greater medial patellar rotation (distal patellar pole rotates medially in frontal plane) at both knee positions (p<0.01), and both VMO and VML activation caused increased anterior patellar translation (p<0.001) in patellofemoral pain compared to healthy subjects at 20° knee flexion. VL activation caused more lateral patellar translation (p<0.001) in patellofemoral pain compared to healthy subjects. In healthy subjects the 3-D mechanical action of the VMO is actively modulated with knee flexion angle while such modulation was not observed in PFP subjects. This could be due to anatomical differences in the VMO insertion on the patella and medial quadriceps weakness. Quantitative evaluation of the influence of individual quadriceps components on patellar tracking will aid understanding of the knee extensor mechanism and provide insight into the etiology of patellofemoral pain.

Keywords: Patella, Tracking, In vivo, Kinematics, Patellofemoral pain, Malalignment