The effect of ankle rotation on cutting of the tibia in total knee arthroplasty
The effect of ankle rotation on cutting of the tibia in total knee arthroplasty
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DOI：
10.2106/jbjs.e.01288
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发表时间：
2006-12-01
影响因子：
5.3
通讯作者：
Iwamoto, Yukihide
中科院分区：
文献类型：
--
作者：
Mizu-Uchi, Hideki;Matsuda, Shuichi;Iwamoto, Yukihide
背景：髓外对准引导器通常用于在全膝关节置换术期间准备胫骨。其缺点之一是导向装置容易受到踝关节位置的影响。胫骨的近端和远端之间可能存在旋转失配。我们假设旋转不匹配可能会导致髓外对准导向器的错误定位，并根据预测的胫骨术后冠状对准来评估这种不匹配。方法：在全膝关节置换术前，使用计算机断层扫描对 51 名患者的 53 个患有内翻畸形的骨关节炎膝关节进行评估。我们使用来自计算机断层扫描数据的三维骨模型定义了踝关节的一根前后轴和胫骨近端的五种不同的前后轴。我们测量了踝关节前后轴和胫骨近端部分之间的旋转角度。髓外导板远端置于踝关节中心前方（踝关节前后轴延长线上），近端置于胫骨近端前后轴延长线上。我们建立了空间坐标来评估旋转角度对预测的胫骨术后冠状对准的影响，并计算了假定的胫骨冠状对准。结果：胫骨近端的所有前后轴的旋转角度均为正（3.60至19.70），表明踝关节相对于胫骨近端部分外旋。对于胫骨近端部分的所有前后轴，预测的胫骨冠状对准均为内翻（0.50 至 5.10）。结论：当在全膝关节置换术中使用髓外对准导向器准备胫骨时，由于胫骨近端部分与踝关节之间的旋转不匹配，可能会发生胫骨假体的内翻对准。 临床相关性：避免使用胫骨假体由于对线不正，当在全膝关节置换术中使用髓外对线引导器时，重要的是要考虑胫骨近端部分和踝关节之间的旋转不匹配。
Background: Extramedullary alignment guides are commonly used to prepare the tibia during total knee arthroplasty. One disadvantage is that the guide is easily affected by the position of the ankle joint. The tibia may have a rotational mismatch between its proximal and distal ends. We hypothesized that a rotational mismatch might cause incorrect positioning of an extramedullary alignment guide and evaluated such a mismatch on the predicted postoperative coronal alignment of the tibia.Methods: Fifty-three osteoarthritic knees with varus deformity in fifty-one patients were evaluated with use of computerized tomography scans before total knee arthroplasty. We defined one anteroposterior axis of the ankle joint and five different anteroposterior axes of the proximal aspect of the tibia using three-dimensional bone models from the computerized tomography data. We measured the rotational angle between the anteroposterior axis of the ankle joint and the proximal part of the tibia. The distal end of the extramedullary guide was placed in front of the center of the ankle joint (on the line of the extended anteroposterior axis of the ankle joint), and the proximal end was placed on the line of the extended anteroposterior axis of the proximal part of the tibia. We established spatial coordinates to evaluate the effect of the rotational angle on the predicted postoperative coronal alignment of the tibia and calculated the presumed tibial coronal alignment.Results: The rotational angle was positive (3.60 to 19.70) for all of the anteroposterior axes of the proximal aspect of the tibia, indicating that the ankle joint was externally rotated relative to the proximal part of the tibia. The predicted tibial coronal alignment was varus (0.50 to 5.10) for all of the anteroposterior axes of the proximal part of the tibia.Conclusions: When an extramedullary alignment guide is used to prepare the tibia in total knee arthroplasty, varus alignment of the tibial component can occur because of a rotational mismatch between the proximal part of the tibia and the ankle joint.Clinical Relevance: To avoid tibial component malalignment, it is important to consider a rotational mismatch between the proximal part of the tibia and the ankle joint when an extramedullary alignment guide is used in total knee arthroplasty.