Influence of the interosseous talocalcaneal ligament injury on stability of the ankle-subtalar joint complex--a cadaveric experimental study.

The present study aims to clarify the influence of the interosseous talocalcaneal ligament (ITCL) injury associated with injury to the lateral ankle ligaments on the ankle-subtalar joint complex motion under conditions of physiologic loading. We conducted mechanical tests using five fresh cadaveric lower extremities. Each specimen was mounted in the loading device and an axial cyclic load from 9.8 to 686 N was applied. Three-dimensional rotations of the ankle and the subtalar joint were measured simultaneously by a linkage electric goniometer. Mechanical tests were repeated after sectioning of the anterior talofibular ligament (ATFL), and again after additional sectioning of the ITCL. In the intact condition, the ankle and the subtalar joints rotated consistently with increase of the load. The predominant rotations were plantar flexion and adduction at the ankle joint, with some eversion demonstrated at the subtalar joint. Although ATFL sectioning did not significantly change the motion of the two joints, additional sectioning of the ITCL significantly increased adduction and total rotation of the ankle joint. The present study demonstrated that a combined injury of the ATFL and the ITCL can induce anterolateral rotatory instability of the ankle joint under conditions of axial loading.