2022, Vol. 26 ›› Issue (36): 5770-5774

Biomechanical properties of a single inferior tibiofibular screw with different angles for fixing inferior tibiofibular injury

Mi Tao, Ding Junwen, Li Zeqing, Tang Baoming, Ren Rong, Li Zhaowei   

Abstract: BACKGROUND: There are still many controversies about how to implant the tibiofibular joint screw. With the gradual development of computer technology, finite element method has been continuously applied in the field of orthopedics, and the reliability of this technology has been greatly improved.
OBJECTIVE: To study the biomechanical characteristics of different angle fixation of the tibiofibular syndesmosis with a single tibiofibular syndesmosis screw by establishing a three-dimensional finite element model of the ankle joint.
METHODS: Based on the CT image, Mimics software and Geomagic Studio software were used to establish the ankle joint model and verify its validity. The model was imported into Solidworks software. The finite element model of fixing the inferior tibiofibular joints with screws at six different angles (Model a: 15° forward, 10° upward, model b: 15° forward, 15° upward, model c: 15° forward, 20° upward, model d: 25° forward, 10° upward, model e : 25° forward, 15° upward, model f: 25° forward, 20° upward) was established to simulate the force mode of the ankle joint when the human body stood on one foot in neutral position. The maximum stress distribution and the maximum displacement of screws with different angle fixing methods were compared.
RESULTS AND CONCLUSION: (1) Under internal rotation and external rotation loads, the maximum stress point of the screw was between the tibia and fibula near the tibia. Under internal rotation load, the maximum stresses of models a, b, c, d, e, and f were 53.38, 52.05, 52.63, 54.39, 53.85, and 52.83 MPa, respectively. Under external rotation load, the maximum stresses of models a, b, c, d, e, and f screw were 73.75, 71.62, 66.81, 77.96, 75.31, and 74.60 MPa, respectively. (2) Under internal rotation load, the maximum displacements of models a, b, c, d, e, and f were 3.27, 3.25, 3.2, 2.83, 2.99, and 2.98 mm, respectively. Under external rotation load, the maximum displacements of models a, b, c, d, e, and f screw were 2.69, 2.71, 2.75, 2.41, 2.53, and 2.55 mm. (3) In conclusion, under internal and external rotation loads, the screw position is fixed at an angle of 25° forward for greater stability.
Key words: inferior tibiofibular, screw, biomechanics, finite element analysis, angle