个体化掌指关节假体三维建模及其髓内柄的计算机辅助设计

目的：自主研发掌指关节假体计算机辅助设计系统，为快速成型技术的个体化掌指关节假体的制造奠定基础。 方法：采用螺旋CT机对尸体手掌指关节进行层厚1 mm扫描，应用自行研发的数据格式转换软件3DMSR进行示指掌指关节三维重建，输入Surface 9.0软件进行髓内柄的计算机辅助设计。 结果：通过CT图像信息的矢量转换及计算机辅助设计，可见髓内腔呈现“漏斗形”，曲面编辑后的关节窝及关节头的假体柄长度分别为47.31和35.20 mm，假体柄符合髓腔大小，而且掌指关节三维重建模型符合人体生理解剖学形状。 结论：利用螺旋CT数据及相关的转化软件进行掌指关节的三维重建，运用工业化软件进行髓内柄的设计，获得精确的掌指关节假体三维实体模型，该模型可以应用于临床。

Three-dimensional reconstruction and CAD of intramedullary stem of individual metacarpophalangeal joint prosthesis

Objective To develop a new system of computer-aided design(CAD) for individual metacarpophalangeal joint prosthesis based on rapid prototyping technique. Methods A hand of cadaver was scanned with PLUS-4 spiral computed tomography (CT).Then the transaxial 2D image data of digitus metacarpophalangeal joint were reconstructed into 3D digitized contour data by 3DMSR that was designed by ourselves. Then,the intramedullary stem was designed in software of Surface 9.0. Results The 3D contour image of metacarpophalangeal joint presented was reconstructed by 3DMSR and edited by Surface 9.0 easily for CAD of individual metacarpophalangeal joint.The intramedullary cavity was like choanoid. The intramedullary stem longitude of articular head and fossa were 47.31 and 35.20 mm.The intramedullary stem fit cavity.The model fit anatomical shape. Conclusion The 3D contour image of metacarpophalangeal joint can be obtained by spiral CT scanning,and the digitized data can be applied directly to CAD of individual artificial joint and subsequently rapid prototyping fabricating.In addition,the reconstruction method is simple and can be applied widely to clinical implant fabricating practice of orthopaedics.