Abstract: Objective　To compare the biomechanical differences among three internal fixation methods by establishing a three-dimensional model of scaphoid waist fracture, so as to provide a method of selection of clinical internal fixation.　Methods　The wrist CT data of a healthy volunteer were selected. The application software was used to establish three internal fixation models of scaphoid waist fracture: a Kirschner wire fixation group, a Herbert screw fixation group, and a nail-feet-fixation device group. Load was applied to the neutral grip position and radial deviation-extension, and the deformation of the scaphoid, and the stress of the internal fixation device were analyzed.　Results　Among three internal fixation devices, the largest deformation of the scaphoid was under the action of the Kirschner wire, and the smallest was under the action of the nail holder. Under the two working conditions, the deformation of the scaphoid and the maximum stress of the fixture was different, but the trend was the same. Under the nail holder, both the scaphoid deformation and the maximum stress were the smallest. But the nail holder had an eccentric effect. When the load reached a critical value, the scaphoid healing surface was easily cracked or asymmetrically eccentric.　Conclusion　Kirschner wire fixation and nail-feet fixation is the worst and best in effect, respectively. The weight of the hand should be properly restricted after nail-feet fixation.

Key words: Scaphoid, 　Waist fracture, 　 Internal fixation, 　Finite element analysis