The Anatomy And Biomechanics Research Of The Interosseous Talocalcaneal Ligament

Objectives: (1)To study the anatomical features and clinical significance of the anterior and posterior interosseous talocalcaneal ligaments under normal conditions.(2)To study the biomechanics and clinical significance of the anterior and posterior interosseous talocalcaneal ligaments.Materials and methods(:1)Anatomical measurement and observation of the anterior and posterior interosseous talocalcaneal ligaments were carried out on 20 cadaver specimens using vernier (0.02mm).All cadaver specimens were made into talus-ligament- calcaneus specimens after removed the ankle joint and sectioned the lateral talocalcaneal ligaments,the medial talocalcaneal ligaments and the deltoid ligaments. The three roots of the inferior extensor retinaculum and the lateral of the talocalcaneal ligaments were exposed after anatomized the structure of the tarsal sinus. Sectioned the talus along the posterior tarsal canal, and then the posterior interosseous talocalcaneal ligaments can be measured and observed using vernier. The anterior interosseous talocalcaneal ligaments can be measured after sectioned the posterior interosseous talocalcaneal ligaments.(2)Load-displacement characteristics ofthe subtalar joint were studied in twelve cadaver specimens.Six of them were abscised the anterior interosseous talocalcaneal ligaments,and others were abscised the posterior ligaments. All the cadaver speciments were cutted the ankle joint, the ankle articular surface of the talus and the post- calcaneus were exposed. Bone blocks were then embedded in polymethylmethacrylate.Drawer directions were defined according to the motion of the calcaneus relative to the talus: anterior motion as the 0°direction, lateral as 90°, posterior as180°, and medial as 270°.Results: (1) The interosseous talocalcaneal ligament lies in the tarsal canal and have a angle of 45°with the tarsal sinus on the coronary plane. The interosseous talocalcaneal ligament consists of the anterior and posterior components. The anterior interosseous talocalcaneal ligament originates in the posterior of the calcaneal groove, accretes between the anterior and middle talar articular surface of the calcaneus, runs to the anterior-superior-lateral part and inserts at the inferior of the talar neck..The anterior ligament is more obliquer than the posterior ligament. The form of the anterior interosseous talocalcaneal ligament is like rhombus or square-built restiform. The posterior interosseous talocalcaneal ligament originates in the posterior-lateral part of the tarsal canal, accretes to the posterior talar articular surface of the calcaneus, runs to the posterior-superior-medial partand inserts at the posterior calcaneal articular surface of the talus. The posterior ligament is under the move axis of the subtalar joint and beside with the medial root of the inferior extensor retinaculum. Actually the posterior ligament is part of the incrassated articular sufface. The form of the posterior interosseous talocalcaneal ligament is like trapezia or square-built"V". (2)There have relativity between the displacement or the increased displacement of the talus and the direction of the experiment. When the anterior interosseous talocalcaneal ligament were cutted, the increased displacement of the talus on the 30°,90°,120°,150°is more than other sides (P<0.01), the talus mostly moved to the anterior-lateral side. And if cutted the posterior interosseous talocalcaneal ligament, the increased displacement of the talus on the 180°,300°,330°is more than other sides (P<0.01), the talus mostly moved to the anterior-interior side.Conclusions: (1) The interosseous talocalcaneal ligament is very strong , it lies in the middle of the subtalar joint, under the move axis of the subtalar joint. The anatomic character of the interosseous talocalcaneal ligament which observed in this experiment tell us the function of the interosseous talocalcaneal ligament is mostly to maintain the articular surface closely enough and to prevent eversion and inversion of the subtalar joint. In addition, because the posterior ligament locates to the posterior-lateral part of the anterior ligament and more stronger than the anterior ligament, so in the function to decreased range of subtalar rotation especially in inversion, the posterior ligament may be more important than the anterior ligament. (2)The anterior and posterior interosseous talocalcaneal ligaments have different roles to maintain stability of the subtalar joint. But the posterior ligament is more important than the anterior ligament. The posterior ligament should be reconditioned first when have an operation.