High ankle sprains are common in contact sports such as football
and soccer. A high ankle sprain typically occurs when an external rotation force
is applied to the ankle in prone position. This type of sprain is characterized
by damage to the interosseous membrane and syndesmotic ligaments that bind the
tibia and fibula. The primary goal of this project is to characterize fibular
and talar motion after syndesmotic injury and surgical fixation with simulated
weight-bearing. Surgical fixation methods tested in this project include:
tricortical screw constructs, suture button constructs, and hybrid constructs.
Testing of a full lower leg cadaveric specimen (shank and foot)
introduces additional constraints not present in knee joint testing. First,
three rigid bodies (tibia, fibula, and talus) must be tracked to determine
kinematics of the high ankle joint. Second, a larger specimen must be fastened
to the robot for testing, which required the construction of custom clamps to
rigidly mount the specimen to the robot. In order to conduct biomechanical
testing of the high ankle joint, an external, 3-dimensional motion tracking
system (OptiTrack) is being used to record the motion of the full length fibula.