Biomechanical Evaluation of Tongue Type Calcaneal Fracture: Finite Element Analysis

• Main Authors: Huang, Yu-Hsuan, 黃語萱
• Other Authors: Hung, Ching-Hua
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/qrttqs

碩士 === 國立交通大學 === 機械工程系所 === 104 === The classification of calcaneal fractures is helpful for the preoperative diagnosis and the decisions of treatment due to the high complexity of types. Nowadays, the most common classification system is Sanders and Essex-Lopresti. In the tongue type fracture of Essex-Lopresti system, tongue fragment connects to the Achilles tendon. The force caused by Achilles tendon may affect the stability of the tongue fragment. Therefore, the biomechanics of tongue type fracture is worth analyzing. Open reduction and internal fixation (ORIF) is a standard surgery for calcaneal fracture, but the stability of fracture fixation between locking and nonlocking screws has been a controversy until now. Recently, minimally invasive techniques using percutaneous fixation (PF) is provoked to reduce these complexity. Because the type of calcaneal fracture is complex and the fixation method of screws is inconsistent, the arrangement of screws must be considered when the calcaneal fracture is treated by PF. The purpose of this study is to use the finite element model to simulate early weight bearing stage in order to evaluate the biomechanical influence and the stability of implant in tongue type. This study will divided two parts: (1) ORIF treatment will compare the stability of the fixation between locking and nonlocking screws. (2) PF treatment will evaluate the difference in three kinds of screws position. In the simulation result of ORIF, the difference of bohler’s angle between locking and nonlocking screws is less than 1ﾟ. Comparably, in the simulation result of PF, the bohler’s angle difference between three kinds of screw positions is less than 1ﾟ. All cases have the high stress on the surface of the subtalar joint. One case of two screws position implanted in parallel from the inferior tuberosity to the posterior facet can transmit the ground reaction force equally and make the less stress on the surface of subtalar joint. The other case of screw position implanted from the superior tuberosity to calcaneocuboid joint has less stress on the inferior tongue fragment. The function of this screw can shift the stress from tongue fragment to the anterior process. ORIF and PF have good stability in tongue type of calcaneal fracture. ORIF with plate using nonlocking or locking screws provided good stiffness and might allow earlier weight-bearing. In the PF, the implanted position of screws might affect the difference of the internal stress distribution between the calcaneal bone fragments.