胫骨近端截骨面与胫骨假体的数字化形态学研究

目的 利用数字化技术获取健康成人正常胫骨近端截而及假体的参数参考值,探讨适合不同人种且具有性别差异的胫骨假体设计.方法 对55名志愿者中的92侧正常膝关节(男42侧,女50侧)进行螺旋CT扫描,将断层扣描数据导入Mimics10.1软件建立膝关节三维数字模型,然后将模型导入Geomagic Studio 8软件系统对胫骨近端模型进行模拟截骨、形态学测量,分析不同性别胫骨近端截面的形态学差异.再将获得的模型与通过激光扫描获得的假体(PFC和Nexgen)三维模型进行模拟装配、参数测量.结果 胫骨近端截骨面的前后径(AP)为(49.87 ±3.90)mm、内外侧横径(ML)为(73.50±5.60)mm,AP与ML呈正相关.男性胫骨平台AP为(53.24±4.10)mm、ML为(75.85±3.50)mm,均比女性[AP为(47.61±3,70)mm,ML为(67.68±2.60)mm]大.内侧前后径(MAP)比外侧前后径(LAP)大,男性平均大(3.90±2.90)mm,女性平均大(3.70±2.70)mm.PFC假体(0.75±0.05)和Nexgen假体(0.69±0.03)的AP/MP比值与本研究正常成人(0.68±0.03)相比,差异均有统计学意义(P<0.05).结论 不同性别及人种的胫骨截面形态存在显著差异,为提高人工膝关节胫骨假体的覆盖率,胫骨假体设计及临床操作均要考虑不同人种和性别的形态学特点.

Morphometry of the proximal tibia for design of tibial prosthesis using digital reconstruction technique

Objective To determine the anthropometric data of the resected proximal tibia in a Chinese population for the design of Chinese tibial prostheses.Methods We carried out anthropometric measurements,using three dimensional computer tomography,of the proximal tibial sections of 92 knees that bad been harvested from 42 male and 50 female Chinese cadavers.We measured the mediolateral(ML),middle anteroposterior(AP),medial and lateral anteroposterior dimensions and the ML/AP ratio of the resected proximal tibial surface.We then compared the data with the parameters of the 2 conventionally used symmetric total knee components(DePuy and Zimmer).Furthermore,the ML/AP ratio of the study population was also compared with that of the currently available prostheses.Results We found that the average ML[(73.50 ±5.60)mm]and AP[(49.87 ± 3.90)mini dimensions of the study population were smaller than those of the commercially available TKA implants.We found the ML/AP ratio decreased with the increase in the AP dimension of the proximal tibia,as compared to the constant ML/AP ratio shown in the conventional tibial prostheses.Both the small and large-sized prostheses were found to be mediolaterally unfitting.Conclusion We suggest redesigning the ML/AP ratio of the tibial component to match the shape of the proximal tibia in the Chinese population.