Evaluating patellar kinematics through magnetic resonance imaging during open- and closed-kinetic-chain exercises.
OBJECTIVE
To evaluate patellar kinematics of volunteers without knee pain at rest and during isometric contraction in open-and closed-kinetic-chain exercises.


METHODS
Twenty individuals took part in this study. All were submitted to magnetic resonance imaging (MRI) during rest and voluntary isometric contraction (VIC) in the open and closed kinetic chain at 15 degrees, 30 degrees, and 45 degrees of knee flexion. Through MRI and using medical e-film software, the following measurements were evaluated: sulcus angle, patellar-tilt angle, and bisect offset. The mixed-effects linear model was used for comparison between knee positions, between rest and isometric contractions, and between the exercises.


RESULTS
Data analysis revealed that the sulcus angle decreased as knee flexion increased and revealed increases with isometric contractions in both the open and closed kinetic chain for all knee-flexion angles. The patellar-tilt angle decreased with isometric contractions in both the open and closed kinetic chain for every knee position. However, in the closed kinetic chain, patellar tilt increased significantly with the knee flexed at 15 degrees. The bisect offset increased with the knee flexed at 15 degrees during isometric contractions and decreased as knee flexion increased during both exercises.


CONCLUSIONS
VIC in the last degrees of knee extension may compromise patellar dynamics. On the other hand, it is possible to favor patellar stability by performing muscle contractions with the knee flexed at 30 degrees and 45 degrees in either the open or closed kinetic chain.
Ribeirão Preto School of Medicine, University of São Paulo, Brazil.
Lílian Ramiro
LR
Felicio
Marcelo Camargo
MC
Saad
Rogério Ferreira
RF
Liporaci
Augusto do Prado
Ado P
Baffa
Antônio Carlos
AC
Dos Santos
Débora
D
Bevilaqua-Grossi
D001696:Biomechanical Phenomena; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D057071:Patellofemoral Joint / Q000502:physiology*; D011187:Posture; D011446:Prospective Studies; D015203:Reproducibility of Results; D012146:Rest / Q000502:physiology; D013223:Statistics as Topic; D055815:Young Adult