A biomechanical study of human lateral ankle ligaments and autogenous reconstructive grafts.

The purpose of this study was to investigate the biomechanical behavior of human anterior talofibular and calcaneofibular ligaments, as well as peroneus brevis, split peroneus brevis, and toe extensor tendon grafts. This article represents the first published data comparing the most frequently injured ankle ligaments to the most commonly used autogenous reconstructive grafts. Twenty fresh human ankles provided the bone-ligament-bone and tendon graft specimens for biomechanical testing on a Minneapolis Testing System. Protocol consisted of cyclic loading at physiologic deflections, followed by several load-deflection tests at varying velocities, followed by a final extremely rapid load to failure test. The load-deflection data for all ligaments and tendons demonstrated nonlinearity and strain rate dependence. The maximum load to failure for the anterior talofibular ligament was the lowest of all specimens tested, while its strain to failure was the highest. The loads to failure of the peroneus brevis and split peroneus tendons were significantly greater than the anterior talofibular ligament and approximately equal to the calcaneofibular ligament. Strains to failure for all tendons were significantly less than ligament strains. The high strain to failure of the anterior talofibular ligament demonstrates its physiologic function of allowing increased ankle plantar flexion-internal rotation, while its low load to failure shows its propensity for injury. The greater strength of the tendon grafts explains the success of most reconstructive procedures in reestablishing stability in chronic ankle sprains; at the same time, the data presented suggest that those surgical procedures sacrificing the entire peroneus brevis tendon are unnecessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical characteristics of human ankle ligaments.

The purpose of this study was to define the biomechanical characteristics of the isolated, individual bone-ligament-bone complexes of the human ankle. Twenty human ankles were dissected of all soft tissues to leave only the tibia, fibula, talus, and calcaneus with their intact anterior talofibular, calcaneofibular, posterior talofibular, and deep deltoid ligaments. Specimens were mounted and tested in a Minneapolis Testing System. Protocol consisted of cyclic loading of each isolated bone-ligament-bone preparation, followed by several constant velocity load-deflection tests at varying deflection rates, followed by a final, extremely rapid load to failure test. All ligaments exhibited nonlinearity and strain rate dependence in their load-deflection data. These properties were correlated with ligament function and trauma. The anterior talofibular ligament, the most commonly injured ankle ligament, had the lowest mean maximum load of the specimens tested, whereas the deep deltoid ligament, the least frequently completely disrupted ankle ligament, had the highest load to failure.

Geometrical constraints on the rotational function of the femoral adductors in man.

Various authors have ascribed differing roles to the adductor muscles of the thigh in producing rotation of the femur. In the present study, measurements have been made on the changes in distance between origin and insertion of the adductor muscles which occur with rotation of the femur. Increases in distance indicate the muscle cannot produce a particular movement, while a decrease in length supports an argument that the muscle has a particular function. Measurements were made for positions of flexion-extension and adduction-abduction as well as anatomical rest. The adductor magnus was found to decrease in length during internal rotation while the adductor longus decreased in length during external rotation in most of the positions studied.