TECHNIQUE FOR IN-VIVO MEASUREMENT OF THE 3-DIMENSIONAL KINEMATICS ANDLAXITY CHARACTERISTICS OF THE ANKLE JOINT COMPLEX

We introduce here a technique to measure the three-dimensional kinemat ics and laxity characteristics of the ankle joint complex in vivo. The system consists of an optoelectric, kinematic data acquisition system that is used to measure the motion of the ankle joint complex in resp onse to controlled moments applied through a system of pneumatic actua tors. As a first step toward development of the method into a quantita tive diagnostic tool for injuries of ankle ligaments, we addressed the following questions: (a) What is the reliability for measurement of r ange of motion and laxity of the ankle joint complex? (b) Are there si gnificant differences in laxity between the left and right joints of a healthy individual? and (c) Are there significant differences in laxi ty of the ankle joint complex between men and women? To answer these q uestions, we performed repeated measures of range of motion and laxity of paired ankles in a population of 18 healthy young individuals. The high intraclass correlation coefficients obtained from the statistica l analysis indicate that the new experimental system is highly reliabl e in measurement of total range of motion and total laxity of the ankl e joint complex. We further concluded that, within the statistical pow er available in our experimental design, there are no significant diff erences in either range of motion or laxity between left and right ank les of healthy individuals or between men and women.