Three-dimensional kinematics of the human knee with intracortical pin fixation.

Knee motion was measured with an instrumented spatial linkage (accuracy, linear +/-500 microns; angular, +/-0.5 degree) fixed with intracortical Kirschner wires in five healthy male volunteers (five knees, judged clinically to be normal). This technique allows an accurate description of the relative angular and linear movements between tibia and femur without the effect of skin movement relative to the bone and without the effect of changing muscle volume. Motion of the tibia relative to the femur was described in terms of three clinically meaningful rotations and three translations between full extension and 60 degrees flexion: (1) abduction and adduction: 3.4 degrees +/- 1.2 degrees; (2) internal and external rotation: 10.6 degrees +/- 2.8 degrees, representing screw home motion; (3) anterior and posterior: 5.2 +/- 1.7 mm, representing roll back phenomenon; (4) proximal and distal: 1.2 +/- 2.7 mm; and (5) medial and lateral: 1.1 +/- 2.6 mm.