计算机辅助髌骨三维形态学及虚拟截骨手术的测量

Morphometric assessment and virtual resection of the patellae on three dimensional CT-based models using computer assisted technology

目的利用计算机辅助技术重建髌骨三维模型，评价髌骨三维形态及验证髌骨截骨时参照“外侧关节面”法（以外侧关节面软骨下骨水平为截骨参照）的可靠性。方法募集髌骨结构正常的接受前十字韧带重建手术的志愿者200例，男100例，女100例。行cT扫描获取膝关节解剖学信息，图像导入医学工程软件Mimics中进行三维重建，构建髌骨三维数字化模型。测量髌骨宽度、厚度、高度、关节面长度及髌骨嵴位置等形态学参数。模拟全膝关节置换术参照“外侧关节面”对髌骨实行虚拟截骨，并对截骨后髌骨相关解剖学参数进行测量。结果测量方法的组间及组内一致性高（组内相关系数〉0．75）。不同性别组髌骨宽度、厚度、高度及关节面长度的差异均有统计学意义（P〈0．05），各参数值女性均较男性小。男性、女性髌骨宽度，厚度比均为1．95±0．11。髌骨宽度及厚度具有正相关性（男性r=0．67，P=0．00；女性r=0．63，P=0．00）。髌骨截骨的总体截骨厚度（9．59±1．53）mm，其中男性（10．21±1．53）mm、女性（8．98±1．27）mm。89％的女性截骨厚度为8-11mm，82％的男性截骨厚度为9-12mm。结论通过CT扫描和医学工程软件构建髌骨三维数字化模型对髌骨进行三维形态学评价具有较高的精确性，髌骨相关形态学参数为全膝关节置换术中髌骨置换提供了参考依据。

Objective To assess patellar morphology and determine the reliability of the subchondral method （resecting the patella at the level of the subchondral bone of the lateral facet） for patellar resection in total knee arthroplasty （TKA） using com- puter assisted technology. Methods Computer tomography examinations were performed in 200 volunteers （100 males, 100 fe- males）. The CT scan images were imported into the Mimics software for generating 3D patellar models. Furthermore, comprehen- sive assessment of patellar morphology and virtually resurfacing the patella were conducted with the three-dimensional models. An anthropometric analysis of variance was used with the models to detect differences between genders both before and after resecting the patellae. Results There was good intra- and inter-observer reliability regarding the dimensional measurements in this study （Intra-class correlation coefficient, ICC 〉 0.75）. Significant gender differences in the patellar width, height, thickness and length of articulating fact were found （P 〈 0.05）. The average patellar width/thickness ratio was 1.95±0.11, regardless of gender, and there was a good correlation between the patellar width and thickness （Male r=0.67, P=0.00, Female r=0.63, P=0.00）. After virtual resec- tion, the mean thickness of resected patellae was 9.59±1.53 mm. The resected thickness in male and female group was 10.21±1.53 mm and 8.98±1.27 mm, respectively. It was found that 89% female patellae were resected between 8 and 11 mm and 82% of male patellae were resected between 9 and 12 mm. Conclusion CT based 3D computer assisted technology is an accurate and effi- cient tool in evaluating the anthropometric patellar dimensions, The anthropometric dimensions of this study could provide basic data for guiding surgical management of the patella in TKA.