Biomechanical characteristics of the distal radius fracture based on three-dimensional finite element model of ulna and radius / 中国组织工程研究

ABSTRACT

BACKGROUND: In recent years, most qualitative studies on the mechanism of distal radius fracture are limited to two-dimensional analysis, which is susceptible to many factors, resulting in unsatisfactory results The use of CT data to establish a three-dimensional finite element model can better evaluate human skeletal variation. OBJECTIVE: To establish a three-dimensional finite element model of the radius and ulna, to test the biomechanics of distal radius fracture and to study the mechanism of distal radius fracture. METHODS: Left upper limb of one 50-year-old healthy female was selected to obtain CT imaging data from distal humerus to middle carpal joint. The three-dimensional finite element model of radius and ulna was established by using three-dimensional finite element analysis software Ansys 16.0. The force load of wrist back extension, palm flexion, ulnar deviation, and radial deviation were simulated. The stress of each part ofthe model under different loads was observed and recorded. The fracture formation and crack direction of distal radius at different model angles were analyzed. RESULTS AND CONCLUSION: (1) When the wrist joint was in dorsal extension position, the compressive stress at the midpoint of the dorsal radial margin ofthe forearm pronation and forearm supination increased with the increase ofthe dorsal extension angle, the tension stress on the volar radius of the forearm pronation and forearm supination increased with the increase of the dorsal extension angle. (2) When the wrist joint was in the metacarpal flexion position, the tension stress at the midpoint of the dorsal radius of the forearm pronation and the forearm supination increased with the increase of the metacarpal flexion angle. The compressive stress on the volar radius of the forearm pronation and forearm supination increased with the increase of the palmar flexion angle. (3) When the forearm was pronated dorsiflexion and supinated metacarpal flexion, the radial crack first appeared on the side of the maximum tension on the surface of the distal radius at the junction of cancellous bone and dense bone, the fracture crack developed along the distal metacarpal to the proximal dorsal end and at an angle of 45 degrees to the bone axis. (4) When the forearm was pronated metacarpal flexion and supinated dorsiflexion, the radial crack first appeared on the side of the maximum tension on the surface of the distal radius at the junction of cancellous bone and dense bone, the fracture crack developed along the far back end to the proximal palmar side and at an angle of 45 degrees to the bone axis. (5) To conclude, with the force load on wrist dorsal extension, metacarpal flexion, ulnar deviation, and radial deviation, the fracture first occurs on the maximum surface tension side of the distal radius at the junction of cancellous bone and dense bone, the direction of the crack is related to the directions of shear stress and tension stress.