利用2D-3D自动注册技术研究TKA术后胫股关节运动

Kinematic study on tibiofemoral joint after TKA using 2D-3D automatic registration technique

目的重建全膝置换(total knee arthroplasty,TKA)膝关节三维运动,研究后稳定型假体之间的运动和接触。方法以16例TKA膝关节为研究对象,获取动态X线透视图像和假体三维模型,建立2D-3D自动注册算法,重建膝关节的三维运动,计算运动学参数并测量假体之间的接触位置。结果单幅X线图像注册时间小于30 s,图像平面内重复性注册精度为0.4 mm和0.5°。高屈曲垫片对膝关节屈曲度和胫骨内外旋无明显改进。股骨假体在胫骨垫片的外侧接触点后移范围大于内侧。稳定柱后方的接触发生在屈膝约30°以后,平均接触范围小于9 mm。结论 2D-3D自动注册技术在精度和效率上达到TKA膝关节在体三维运动测量要求,测量结果对TKA膝关节生物力学研究和改进假体设计具有参考意义。

Objective To reconstruct the 3D motion of the knee joint after total knee arthroplasty （TKA） and measure the kinematics and the articular contacts between the posterior stabilized TKAs. Methods Sixteen knees undergoing TKAs were scanned by fluoroscopy. An algorithm of automatic registration was developed to match the 3D TKA models and 2D images. The kinematical parameters and articular contact of the tibiofemoral joint was investigated. Results The time for a single image was less than 30 seconds. The in-plane repeatability was within 0.4 mm and 0.,5 degree. The application of the high-flex insert didn＇ t obviously improve the ability of the flexion and the internal/external tibial rotation. When the knee flexed, the contact point on the lateral side moved more posteriorly than that on the medial side. The contact between the post-cam and the femoral prosthesis occurred with the flexion at about 30 degrees. The average range of the contact was within 9 mm. Conclusions The 3D kinematics of the in vivo TKA knee joint was accurately measured by using 2D-3D automatic registration technique. The result can provide references for the biomechanical study of TKA knees and the improvement of TKA prosthesis design.