Topological optimization of locking plate stiffness for distal radial fracture

Abstract

Objective To optimize the topological design of locking plate for distal radial fracture so that the internal fixation stiffness can be customized. Methods Models of both the distal radial fracture and the conventional locking plate fixation were constructed using software for three-dimensional modeling and computer-aided design. Based on the data from our previous finite element analysis, a decrease of 33.33% in axial stiffness but retention of more than 90.00% in torsional stiffness were defined as the optimization limits. The conventional plate was redesigned by way of topological optimization iterations. Finite element analysis was done to compare stiffness and interfragmentary strain (IFS) between the new optimized design and conventional design of the locking plate under both compressive and torsional loads. Results The axial stiffness of the optimized plate was 636.5 N/mm with a downgrading magnitude of 19.7% which was close to the given limit; the torsional stiffness was 634.12 Nmm/° with a downgrading magnitude of 8.8% which remained under the given limit. In the optimized design, a more significant increase was observed in axial IFS than that in shear IFS, leading to a similar effect as the stiffness regulation did. Conclusion The optimized design of locking plate for distal radial fracture can provide a reliable solution for customized regulation of the internal fixation stiffness. Key words: Radius fractures; Bone plates; Finite element analysis; Topology optimization; Biomechanics