两种3D打印截骨导板在全膝关节置换模型预手术的应用探讨

Comparison of two kinds of 3D-printed osteotomy guide plate in 3D model test-operation for total knee arthroplasty

目的比较两种3D打印截骨导板在全膝关节置换（TKA）模型预手术中的应用效果。方法选取2015年6月行TKA的15例患者行带标定器的下肢全长负重X线正、侧位片及膝关节薄层CT扫描。男6例，女9例；年龄53～86岁，平均67．8岁；左膝7例，右膝8例。利用统计形状模型（SSM）技术及2D／3D配准技术建立下肢模型，进行数字化模拟手术，确定截骨角度及位置。根据确定的截骨方案，用2种思路设计截骨导向器，分别为截骨槽组（锯片直接套入导向器上的截骨槽进行截骨）及定位钉组（导向器确定无头钉位置，根据无头钉位置确定金属截骨模块位置），将两种截骨导向器及由薄层CT重建的膝关节3D模型用聚乳糖材料3D打印成实物。在模型上进行预手术，通过回顾其病例资料与治疗结果观察两种截骨导板的优、劣。结果截骨槽组与定位钉组截骨时间平均分别为（36．5±6．2）、（27．8±4．3）min，断裂率分别为26．7％（8／30）、0，截骨片厚度偏差平均分别为（3．4±2．5）、（1．6±1．7）mm，以上项目两组间比较差异均有统计学意义（P〈0．05）。截骨槽组与定位钉组打印时间平均分别为（307±28）、（302±25）min，差异无统计学意义（P〉0．05）。结论在3D打印模型TKA预手术中，较带截骨槽的截骨导板，确定定位钉的截骨导板截骨时间更短、截骨片厚度更接近术前规划、截骨面平整度更好、导板断裂率更低，但3D打印时间相当。

Objective To compare 2 kinds of 3D-printed osteotomy guide plate in the 3D model test-operation for the total knee arthroplasty （TKA） . Methods Enrolled in this study were 15 patients who underwent TKA from 1st to 30th in June 2015. They were 6 males and 9 females, aged from 53 to 86 years （average, 67.8 years） . Seven left knees and 8 right ones were involved. They took calibrated weight-bearing full-length lower-limb X-ray films and thin-slice CT scans of the knee. The lower limb models were constructed using the statistical shape model （SSM） and 2D/3D registration technology. In the simulated digital operation, the angle and position of osteotomy were determined. According to the osteotomy plan, 2 kinds of guide plate were designed, groove guide plate （GG group） and screw positioning guide plate （SPG group）. The 2 kinds of guide plate and the 3D knee models were 3D-printed using polylaetic acid. Then the groove guide plate and the screw positioning guide plate were used and compared in the model test-operations. Results The osteotomy time was 36.5± 6.2 minutes in GG group and 27.8 ± 4. 3 minutes in SPG group; the rate of breakage was 26.7% （8/30） in GG group and 0 in SPG group; the thickness deviation of the bone cut was 3.4± 2.5 mm in GG group and 1.6± 1.7 mm in SPG group. All the comparisons above showed significant between-group differences （P 〈 0.05） . There was no significant difference in the 3D-printing time between the 2 groups （307 ±28 minutes versus 302 ± 25 minutes） （ P 〉 0.05）. Condusions In the 3D model test-operation for TKA, compared with groove guide plate, application of screw positioning guide plate may lead to less osteotomy time, less thickness deviation of the bone cut from the plan, smoother osteotomy surface and lower breakage rate, but similar 3D-printing time.