| Objective: To get objective evidence of the optimal stress condition in broken ends of scaphoid loins fracture, to provide biomechanical basis for the clinical choice of the different fixation postures after scaphoid loins fracture and further to offer theoretical instructions for the treatment after scaphoid loins fracture, stress distribution and shift rules after three types of fracture in scaphoid loins (transverse fracture, radialis oblique fracture and ulnar side oblique fracture) were studied using electrometric method and three-dimensional (3-D) finite element analysis(FEA).Methods : Electrometric method and three-dimensional finite element analysis were adopted to biomechanical test to the different fixation postures after scaphoid loins fracture. 1. Electrometric method: Fifteen wrist joint were choosed from male adult corpses and made three types of fracture models to part transverse fracture (fracture line perpendicularity in scaphoid longitudinal axis), radialis oblique fracture (fracture line from radialis proximum to ulnar distally) and ulnar side oblique fracture (fracture line from ulnar distally to radialis proximum). Then fracture models were measured using the electrometric method after fixed in the different fixation postures. 2. Three-dimensional finite element analysis: A set of consecutive transactional computerized tomography images of right wrist joint from a normal male volnteer (scan range from 10cm above wrist articular facet to metacarpophalangeal joints facet) was selected and all images were divided into 4996 nodes and 3015 units as per the principle of three-dimensional finite element. Through the Super-Sap finite element calculation procedure the 3-D model of the normal wrist joint was then established. On the basis of the normal model, the three 3-D models of scaphoid lions fracture were formed by changing elastic modulus, poisson's ratio and shear modulus of some units in these models into granulation tissue and after...
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