Effect of hinge length on the lateral cortex fracture in high tibia osteotomy: an XFEM study

The main disadvantage of high tibial osteotomy (HTO) is the fracture of the lateral hinge during surgery. Therefore, the present study was designed to investigate the effect of different hinge lengths on the fracture type of the lateral hinge during the opening in HTO. For this purpose, extended finite element method (XFEM) was used to predict the crack initiation and growth in bone cortex in twelve models, each with different hinge lengths and medial start points. It was shown that extending the hinge length from 5 to 10, 16 and 22 mm increased the maximum principal stress around the hinge, and thus the fracture probability. A minimal effect on the results was observed by changing medial starting point of the cut from 30 to 35 and 40 mm. As a result, the extended finite element analyses confirmed the hypothesis that the extension of hinge segment increases the likelihood of a type II and type III fractures.