Development of personalized osteotomy technique for the first metatarsal bone

Surgical methods form the basis of modern approach to forefoot deformities correction. Scientific and practical interest in this topic is based on the patients' growing need for specialized care, which is required by 64% of women and 25% of men. In most cases, there is bilateral deformation of both feet. Some scientists are strongly against simultaneous surgery on both feet. It is obvious that the solution regarding acceptability of the load in the early postoperative period requires quantitative individual assessment. This assessment can be performed using biomechanics. This paper presents the technique for assessing the bone-screw system when performing corrective osteotomies of the first metatarsal bone based on biomechanical methods. This technique allows to perform comparative analysis of various osteotomy methods for a particular patient. In this study we examined Chevron and Scarf osteotomy with displacement of bone fragments by 1/3 and 2/3 with different fixation variants. To solve this problem, personalized geometric models of the first metatarsal bone were built on the basis of computed tomography data using 3D Slicer and SolidWorks systems. The implant models were built as well. Finite element analysis was carried out using Ansys Workbench software. The focus of the study was to analyse stresses that occur on the plantar surface of the first metatarsal bone head during walking. Assessment of the maximum allowable shift of bone fragments for normalization of the forefoot deformities was carried out. The developed technique allows to choose osteotomy variant and justify the possibility of simultaneous surgery on both feet for a particular patient. © 2019 SPIE.