Spring Ligament and Sustentaculum Tali Anatomical Variations: Anatomical Research Oriented to Acquired Flat Foot Study

Abstract

Background: Acquired flat foot is generated by the fall of the medial arch of the foot. Spring Ligament (SL) lesions and posterior tibial insufficiency have been associated with fall of medial arch. In addition, some variations of sustentaculum tali have been associated with subtalar joint osteoarthritic changes and a high risk of acquired flat foot. Anatomical variations of spring ligament have been reported. Thus, some authors observed two fascicles that composed the ligament and some observed three fascicles. The purpose of this research is to study the anatomical variations of SL and its relations with the sustentaculum tali anatomical variations to establish which fascicles of spring ligament might coincide with a sustentaculum tali-risk factor for acquired flat foot. Materials and Methods: Fifteen feet in 10% formalin solution were reviewed. Anatomical dissections of subtalar joint were done, and the spring ligament fascicles and sustentaculum tali variations were studied. Results: A correlation was found between the type of sustentaculum tali and the numbers of fascicles that composed the ligament. Sustentaculum tali with two articular facets were related to spring ligaments with three fascicles, and sustentaculum tali with one articular surface were related to spring ligaments with two fascicles. The third fascicle of spring ligament was observed along with sustentaculum tali described as more stable and with less osteoarthritic changes. This observation might implicate a special role of the third fascicle in the stability of subtalar joint and the pathogenesis of acquired flat foot.