Axial rotation of the knee in women

Eighty-five women with normal left knees were measured to determine the active axial rotation that is normally present at the tibiofemoral joint. Subjects were seated with the leg perpendicular to a measuring platform placed at floor level and rotation was measured with the knee flexed at 70, 90, and 110°. Mean total rotation was found to increase from 35 to 40 to 44° as the knee flexion angle increased (P<0.01). External rotation from the neutral position at all angles of flexion was approximately twice that of internal rotation. These values are in general agreement with those obtained in earlier studies, but are different from values given in many textbooks. Although precise measurement of axial rotation is difficult in a clinical setting, an approximation of symmetrical rotation can be made.