A Biomechanical Evaluation of the Tibiofibular and Tibiotalar Ligaments of the Ankle

Abstract

The purpose of this ex vivo biomechanical study was to determine the strength and stiffness of the anterior and posterior syndesmotic tibiofibular ligaments and the posterior tibiotalar component of the deltoid ligament. Injuries to these ligaments are a prevalent clinical problem, yet little is known about their mechanical behavior. Ten fresh-frozen cadaver lower extremities (average age at death, 72 +/- 8 years) were harvested. The anterior and posterior tibiofibular ligaments and the posterior tibiotalar component of the deltoid were isolated and prepared as bone-ligament-bone complexes for tensile testing to determine strength, stiffness, and mode of failure. The posterior tibiofibular ligament exhibited greater strength, but not significantly so (p < .05), than the anterior tibiofibular ligament and the posterior tibiotalar component of the deltoid ligament. There were no significant differences in stiffness between the three ligaments tested. The dominant mode of failure for the anterior tibiofibular ligament was ligament substance rupture, primarily near its fibular insertion, whereas the failure modes of the posterior tibiofibular ligament were evenly split between substance ruptures and fibular avulsions. The posterior tibiotalar component of the deltoid ligament ruptured most often near the talar insertion. The tibiofibular ligaments showed greater strength than the lateral collateral and deltoid ligaments, as mentioned in literature. The greater strength of the tibiofibular ligaments relative to the lateral collateral and deltoid ligaments suggests that these ligaments play an important role in ankle constraint.

Development and Validation of a Computational Model to Study the Effect of Foot Constraint on Ankle Injury due to External Rotation

“…Reported ligament stiffness values have a relatively large range. 2,15,20,29,35 To assess the sensitivity of the simulations and further validate the computational models, the effect of variations in ligament stiffness on model outcomes was studied by performing an additional simulation that mimicked the experimental setup of Wei et al 44 To quantify the effect of ligament stiffness, first, all ligament spring stiffnesses were together either increased by 25% or decreased by 25%. Second, strains of each ligament at 40°e xternal foot rotation were compared and those ligaments that had more than 10% strain were selected to individually vary their stiffnesses by ±25%.…”

The effects of tibiofibularis anterior ligaments on ankle joint biomechanics

“…[3] Distal fibula is firmly attached at the tibial notch of the tibia by several syndesmotic ligaments. [3,5] There are three main ligaments that add stability to distal tibiofibular syndesmosis including the anterior inferior tibiofibular ligament (AITFL), the posterior tibiofibular ligament (PITFL), and the interosseous ligament. [1][2][3][4] Anterior inferior tibia fibular ligament is a flat strong ligament that originates from the longitudinal tubercle on the anterior aspect of the lateral malleolus and fibers course superiorly and medially attaching on the anterolateral tubercle of tibia.…”

“…[5,14] In this study, talus anterior displacement was measured under axial load in two situations of intact anterior inferior tibiofibular ligament and sectioned anterior inferior tibiofibular ligament. The aim of the present study was to examine the mechanical behavior of human ankle AITFL at same force (800 Newtons) and investigate the instability of talus biomechanically.…”

“…The incidence of syndesmosis injuries is reported 1% to 11% of all ankle injuries. [3][4][5] Although much research has focused on injury to lateral ankle ligaments and inversion ankle sprain, studies in the literature regarding the injury of the anterior inferior tibiofibular ligament are limited. [3] Syndesmotic injuries are still often undetected and diagnosed only after a simple ankle sprain fails to heal.…”

Syndesmotic Injuries in Athletes

“…A high degree of false positives secondary to subjective interpretation has been shown. Excessive translation is more often seen with the most severe injuries [65,66]. The crossed-leg test is a more recently described test.…”