3D Printing and Computer-Aided Design for Precision Osteotomy-Aided Modules in Bone Biomechanical Study.

Precise and shape-matching osteotomy models are determinants of the experimental homogeneity in the assessment of orthopedic biomechanical properties. At present, however, publications on detailed description of osteotomy in bone biomechanical study are scanty. The purposes of this study were to design a new method of osteotomy-aided module production for bone biomechanical study with the help of three-dimensional (3D) printing and computer-aided design (CAD) and to test the accuracy of osteotomy. Fourteen fourth-generation composite femurs were analyzed. The composite bone was scanned using computed tomography (CT) scanner and loaded in Mimics for reconstruction and, then, imported into 3-Matic software to design intertrochanteric region, distal femur, and rotation control lever models. 3D printer was used to print each component. After assembling Sawbones and osteotomy modules, a horizontal band-saw was used to create fracture models. The volume and mass of intermediate fragments were calculated and analyzed. Satisfactory osteotomies of all composite Sawbones were achieved. The mean volume and mass of intermediate fragments were 21.0 ± 1.5 mm and 19.0 ± 1.2 g, respectively. Range of deviation from average of volumes was -1.9 - 2.8 mm and most of these deviations fall within the range of -1.4 - 2.1 mm. Range of deviation from average of mass was -2.0 - 1.6 g and most of these deviations fall within the range of -1.4 - 1.6 g. One-dimensional histogram of deviation from average shows the precise and stable osteotomy performed based on the modules accordingly. A new method of osteotomy-aided module production for bone biomechanical study with the help of 3D printing and CAD was designed and the accuracy of osteotomy was verified. This method is expected to achieve homogeneity and standardization of osteotomy in bone biomechanical study.