Lad Dnyanesh G, Thilak Jai, Thadi Mohan
Department of Orthopaedic Surgery, Arthroplasty and Sports Medicine, Amrita Institute of Medical Sciences and Research Institute, Kochi, Kerala, India.
Indian J Orthop. 2013 Jan;47(1):77-82. doi: 10.4103/0019-5413.106915.
Incorrect positioning of the implant and improper alignment of the limb following total knee arthroplasty (TKA) can lead to rapid implant wear, loosening, and suboptimal function. Studies suggest that alignment errors of > 3° are associated with rapid failure and less satisfactory function. Computer navigated systems have been developed to enhance precision in instrumentation during surgery. The aim of the study was to compare component alignment following computer assisted surgery (CAS) and jig based TKA as well as functional outcome.
This is a prospective study of 100 knees to compare computer-assisted TKA and jig-based surgery in relation to femoral and tibial component alignment and functional outcome. The postoperative x-rays (anteroposterior and lateral) of the knee and CT scanogram from hip to foot were obtained. The coronal alignment of the femoral and tibial components and rotational alignment of femoral component was calculated. Knee society score at 24 months was used to assess the function.
Results of our study show that mean placement of the tibial component in coronal plane (91.3037°) and sagittal planes (3.6058°) was significantly better with CAS. The difference was statistically insignificant in case of mean coronal alignment of the femoral components (90.34210° in navigation group and 90.5444° in jig group) and in case of the mean femoral condylar twist angle (external rotation 2.3406° in navigation group versus 2.3593° in jig group).
A significantly improved placement of the component was found in the coronal and sagittal planes of the tibial component by CAS. The placement of the components in the other planes was comparable with the values recorded in the jig-based surgery group. Functional outcome was not significantly different.
全膝关节置换术（TKA）后植入物定位不正确以及肢体对线不当可导致植入物快速磨损、松动和功能欠佳。研究表明，对线误差>3°与快速失败和功能不太满意有关。已开发出计算机导航系统以提高手术中器械操作的精度。本研究的目的是比较计算机辅助手术（CAS）和基于定位器的TKA后的组件对线情况以及功能结果。
这是一项对100个膝关节的前瞻性研究，比较计算机辅助TKA和基于定位器的手术在股骨和胫骨组件对线以及功能结果方面的情况。获取了膝关节术后的X线片（前后位和侧位）以及从髋部到足部的CT扫描图像。计算了股骨和胫骨组件的冠状面对线以及股骨组件的旋转对线。使用24个月时的膝关节协会评分来评估功能。
我们的研究结果表明，CAS组胫骨组件在冠状面（91.3037°）和矢状面（3.6058°）的平均放置明显更好。股骨组件的平均冠状面对线情况（导航组为90.34210°，定位器组为90.5444°）以及平均股骨髁扭转角度（导航组为外旋2.3406°，定位器组为2.3593°）方面，差异无统计学意义。
通过CAS发现胫骨组件在冠状面和矢状面的放置有显著改善。其他平面组件的放置与基于定位器的手术组记录的值相当。功能结果无显著差异。
