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Patellofemoral kinematics during knee flexion‐extension: An in vitro study
Author(s) -
Amis Andrew A.,
Senavongse Wongwit,
Bull Anthony M. J.
Publication year - 2006
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20268
Subject(s) - patella , kinematics , anatomy , cadaver , medicine , knee flexion , knee joint , tibia , orthodontics , range of motion , physics , physical therapy , surgery , classical mechanics
The purpose of this work was to obtain kinematics data for the normal human patellofemoral joint in vitro. Eight fresh‐frozen cadaver knees were used. The heads of the quadriceps were separated, and the knees mounted in a kinematics rig. The femoral axis was aligned with an electromagnetic transmitter. The six heads of the quadriceps, including vasti medialis and lateralis obliquus, were loaded via cables according to their physiological cross‐sectional areas and orientations. Magnetic trackers were mounted on the patella and tibia. The knee was flexed‐extended against the extending muscle action, and patellar tracking was measured in six degrees of freedom. As the knee flexed, the patella flexed by 0.7 times the tibiofemoral flexion angle. It also translated medially 4 mm to engage the trochlear groove at 20° knee flexion, then translated to 7 mm lateral by 90° knee flexion. The patella tilted progressively to 7° lateral by 90° knee flexion, and patellar medial‐lateral rotation was usually less than 3°. This is believed to be the first set of patellar tracking data obtained in both flexion and extension motion while the patella was acted on by a full set of quadriceps muscle tensions acting in physiological directions. These data may be used in future studies of the effects of pathologies on patellar tracking. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res