TY - JOUR
T1 - Internal/external rotation moment arms of muscles at the knee
T2 - Moment arms for the normal knee and the ACL-deficient knee
AU - Buford, W. L.
AU - Ivey, F. M.
AU - Nakamura, T.
AU - Patterson, R. M.
AU - Nguyen, D. K.
N1 - Funding Information:
Primary funding for this study was a research project supported by Sulzer Orthopaedics USA, Austin, TX. It is also supported by grant number 004952-0111-1999, from the Advanced Technology Program of the Texas Higher Education Coordinating Board.
PY - 2001
Y1 - 2001
N2 - Knowledge of the three-dimensional balance of loads at the knee joint is required to adequately assess the treatment and rehabilitation of the malfunctioning knee. This report focuses upon the moment arms for the knee in internal/external (IE) rotation motion. It augments prior work that defined flexion/extension moment arms. Muscle excursions and angular motion of the lower leg during IE rotation were measured in 17 fresh-frozen hemi-pelvis specimens. Moment arms were calculated as the derivatives of excursion with respect to the angle. Rotational motion was performed for the normal and anterior cruciate ligament (ACL)-deficient knee. Of the 13 muscles measured at the knee, seven were significant contributors to IE rotation: the biceps femoris long and short head externally rotate opposite the gracilis, sartorious, semimembranosis, semitendonosus and popliteus, functioning as internal rotators. Moment arm magnitudes were greatest with the knee in a flexed position (internal [external] rotators peaked at 70° [90°] flexion). At 30° flexion, the IE rotation moment arm minima and maxima were 10.1-11.6, 6.8-9.0, 6.0-15.7, 8.2-14.1 and 0.0-10.4 mm for the semimembranosis, semitendonosus, gracilis, sartorius and popliteus, and 14.7-27.9 and 18.5-31.5 mm for the biceps femoris short and long, respectively. Moment arms for the ACL-deficient condition were significantly changed only at extremes of flexion-extension.
AB - Knowledge of the three-dimensional balance of loads at the knee joint is required to adequately assess the treatment and rehabilitation of the malfunctioning knee. This report focuses upon the moment arms for the knee in internal/external (IE) rotation motion. It augments prior work that defined flexion/extension moment arms. Muscle excursions and angular motion of the lower leg during IE rotation were measured in 17 fresh-frozen hemi-pelvis specimens. Moment arms were calculated as the derivatives of excursion with respect to the angle. Rotational motion was performed for the normal and anterior cruciate ligament (ACL)-deficient knee. Of the 13 muscles measured at the knee, seven were significant contributors to IE rotation: the biceps femoris long and short head externally rotate opposite the gracilis, sartorious, semimembranosis, semitendonosus and popliteus, functioning as internal rotators. Moment arm magnitudes were greatest with the knee in a flexed position (internal [external] rotators peaked at 70° [90°] flexion). At 30° flexion, the IE rotation moment arm minima and maxima were 10.1-11.6, 6.8-9.0, 6.0-15.7, 8.2-14.1 and 0.0-10.4 mm for the semimembranosis, semitendonosus, gracilis, sartorius and popliteus, and 14.7-27.9 and 18.5-31.5 mm for the biceps femoris short and long, respectively. Moment arms for the ACL-deficient condition were significantly changed only at extremes of flexion-extension.
KW - Joint mechanics
KW - Moment arms
KW - Muscle balance
KW - Muscle mechanics
UR - http://www.scopus.com/inward/record.url?scp=0034786496&partnerID=8YFLogxK
U2 - 10.1016/S0968-0160(01)00106-5
DO - 10.1016/S0968-0160(01)00106-5
M3 - Article
C2 - 11706692
AN - SCOPUS:0034786496
VL - 8
SP - 293
EP - 303
JO - Knee
JF - Knee
SN - 0968-0160
IS - 4
ER -