title: In vivo tracking of the human patella using cine phase contrast magnetic resonance imaging.
abstract: Improper patellar tracking is often considered to be the cause of patellar-femoral pain. Unfortunately, our knowledge of patellar-femoral-tibial (knee) joint kinematics is severely limited due to a lack of three-dimensional, noninvasive, in vivo measurement techniques. This study presents the first large-scale, dynamic, three-dimensional, noninvasive, in vivo study of nonimpaired knee joint kinematics during volitional leg extensions. Cine-phase contrast magnetic resonance imaging was used to measure the velocity profiles of the patella, femur, and tibia in 18 unimpaired knees during leg extensions, resisted by a 34 N weight. Bone displacements were calculated through integration and then converted into three-dimensional orientation angles. We found that the patella displaced laterally, superiorly, and anteriorly as the knee extended. Further, patellar flexion lagged knee flexion, patellar tilt was variable, and patellar rotation was fairly constant throughout extension.
authors.affiliation: Mechanical Engineering Department, Catholic University of America, Washington, DC 20064, USA.
authors.forename: F T
authors.initials: FT
authors.lastname: Sheehan
authors.forename: F E
authors.initials: FE
authors.lastname: Zajac
authors.forename: J E
authors.initials: JE
authors.lastname: Drace
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007719:Knee Joint / Q000502:physiology; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008954:Models, Biological; D010329:Patella / Q000033:anatomy & histology* / Q000502:physiology*; D016684:Prone Position; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D016474:Weight-Bearing / Q000502:physiology