SYMPOSIA PAPER Published: 01 January 1989

Three-Dimensional Loading of the Knee During Internal-External Rotation: The Effect of Ankle Constraint


Torsional laxity and stiffness of the knee joint are often determined by rotating the foot with a torque measuring instrument and then measuring the rotations generated across the knee with a goniometer. However, when an internal-external rotation is applied to the foot, significant three-dimensional forces and moments are produced at the knee. These forces and moments depend on the external constraint of the ankle complex, and, as a result, the laxity of the knee also depends on the ankle constraint. Tests are conducted with the foot of a subject in a shoe, with and without the ankle taped, and in a buckled and unbuckled (ski) boot. The average laxity of the primary (linear) region of the axial moment versus internal-external rotation is 36% greater when the ankle is constrained by the buckled boot than it is in the other cases of lesser ankle constraint.

Author Information

Quinn, TP
University of California, Berkeley, CA
Mote, CD
University of California, Berkeley, CA
Skinner, HB
University of California, San Francisco, CA
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Developed by Committee: F27
Pages: 252–266
DOI: 10.1520/STP19474S
ISBN-EB: 978-0-8031-5083-6
ISBN-13: 978-0-8031-1197-4