Comparisons of the Normal Ankle Laxity and Motion of the Talus during Constrained and Unconstrained Laxity Tests
Date Issued
2015
Date
2015
Author(s)
Chung, I-Lun
Abstract
Ankle injuries occur in a variety of sports. Among the many ankle injuries, ankle sprain is accounted for 75%, including 85% of the sprain is inversion trauma. Not properly handled when after numerous ankle injuries, 73% of sprained athletes have recurrent ankle sprains, and 59% of athletes who suffered recurrent ankle sprains have significant residual symptoms and disability, resulting in ankle instability which further affect athletic performance. Therefore, explore for ankle stability is an important issue. The main target of this study was to measure ankle stability and motion of talus under anterior drawer test in different conditions. This study combined the digital image correlation system (DIC), biomedical image process, and robotic-based joint testing system (RJTS). The experiments were conducted simulating clinical physical examination of anterior drawer test and using high-pixel synchronized cameras to capture talus motion during the process. Then altered the control method, conducted the anterior drawer test with position control in the anterior/posterior direction while force control in other five degree-of-freedoms. Three-dimensional articular surfaces were reconstructed using DIC system. These articular surfaces were matched with bone models reconstructed by CT scan to get complete bone models which contains cartilages and bones. During the anterior drawer test, the interlaced sections of cartilages of tibia and talus are considered the deformations of cartilage, and the distribution of deformation on the articular surfaces can be derived by proper calculation. The results suggested that during simulated clinical physical examination of anterior drawer test compared to the force controlled anterior drawer test, the contact area of articular surfaces is larger, the cartilage deformation is more significant, the motion of talus is more unpredictable, the joint laxity is less stable, and the joint stability is poorer. This indicates that clinical treatments could be harmful if improper force is applied on injured ankle.
Subjects
Ankle Joint
Robotic-based Joint Testing System
Digital Image Correlation
Anterior Drawer Test
Type
thesis