MAPPING THE ANKLE JOINTS PASSIVE MOTION AND MEASURING THE EFFECT OF INJURY ON LIGAMENT CONSTRAINT AT THE ANKLE JOINT

Abstract

Lateral ankle sprain is one of the most common sports injuries, and having a better understanding of how ligament constraint changes after injury can assist in accurately diagnosing ankle laxity, prevention, and recovery. The objective was to map out the range of motion of the ankle under constant torque loading, and to examine the effect of a lateral ankle sprain level 2 and 3. Nine cadaveric ankles were run through a range of motion where a 6 degree of freedom load cell was used to collect force and torque loads and an Optotrak scanner collected the position of the tibia, talus, and calcaneus. The ankle saw more motion in abduction and inversion than adduction and eversion in the talocrural joint, and the ankle joint complex. The subtalar joint saw no change in inversion or eversion, or adduction, but there was less than four degrees of motion in adduction while the foot was plantarflexed. In general the foot was insensitive to varying torque levels with or without injury except in the talocrural joint where inversion and eversion saw a three to four degree difference after a sprain level 3. It was observed that when ABAD torques were applied the ankle was free to move in INEV, but when INEV torques were applied there was a constraint that limited the motion of the ankle in the ABAD direction. The results from this study show the range of motion of the ankle intact, and with a level 2 and level 3 sprain in the subtalar joint, the talocrural joint, and the ankle joint complex. With knowledge of the ankle's envelope of motion and quantitative assessment of the Taylor tilt test could be created, as well during a total ankle replacement different mid-flexion assessments could be made to create better outcomes for patients.