Establishment of three-dimensional finite element model and biomechanical analysis of normal metacarpophalangeal joint

Objective To establish a precise three-dimensional finite element model of the second to fifth metacarpophalangeal joints to simulate the stress distribution of the second to fifth metacarpal and phalangeal bones under different loads. Methods A healthy male volunteer was selected to perform 64-slice spiral CT scanning on his right hand. The data were extracted by Mimics 17.0 software. The second to fifth metacarpal and phalangeal bones and cartilage joint models were reconstructed. After the model was modified and assembled, it was imported into Hypermesh 13.0 software in iges format for meshing, and the BDF format file was derived. Finally, the data were put into the MSC. Patran/Nastran2012 software. Ten, twenty, thirty, forty and fifty Newton loads were applied along the longitudinal direction of phalanges to analyze the stress distribution of metacarpal and phalangeal bones. Results A high-precision three-dimensional finite element model of metacarpophalangeal joints was established, with a total of 40 070 nodes and 178 903 tetrahedral elements. The solid element meshes were used for metacarpal and phalangeal bones and cartilage joints. With the increase of load, the peak stress of metacarpal and phalangeal bones ranges from 0.64 to 8.65 MPa, and the overall stress of the fourth metacarpal and phalangeal bone was significantly higher than that of other metacarpal and phalangeal bones, of which the third metacarpal and phalangeal bone suffered the least stress. Conclusion The finite element model established by Mimics and MSC. Patran/Nastran software has higher accuracy and can better simulate the biomechanical properties of metacarpophalangeal joints, which can be used in biomechanical analysis experiments. Key words: Metacarpophalangeal joint; Finite element analysis; Stress; Three-dimensional reconstruction; Digital orthopaedics