Pitto R P, Graydon A J, Bradley L, Malak S F, Walker C G, Anderson I A
University of Auckland, and Department of Orthopaedics, Middlemore Hospital, 93311 Otahuhu, Auckland, New Zealand.
J Bone Joint Surg Br. 2006 May;88(5):601-5. doi: 10.1302/0301-620X.88B5.17431.
The object of this study was to develop a method to assess the accuracy of an image-free total knee replacement navigation system in legs with normal or abnormal mechanical axes. A phantom leg was constructed with simulated hip and knee joints and provided a means to locate the centre of the ankle joint. Additional joints located at the midshaft of the tibia and femur allowed deformation in the flexion/extension, varus/valgus and rotational planes. Using a digital caliper unit to measure the coordinates precisely, a software program was developed to convert these local coordinates into a determination of actual leg alignment. At specific points in the procedure, information was compared between the digital caliper measurements and the image-free navigation system. Repeated serial measurements were undertaken. In the setting of normal alignment the mean error of the system was within 0.5 degrees . In the setting of abnormal plane alignment in both the femur and the tibia, the error was within 1 degrees . This is the first study designed to assess the accuracy of a clinically-validated navigation system. It demonstrates in vitro accuracy of the image-free navigation system in both normal and abnormal leg alignment settings.
本研究的目的是开发一种方法，以评估无图像全膝关节置换导航系统在机械轴正常或异常的腿部的准确性。构建了一个带有模拟髋关节和膝关节的幻影腿，并提供了一种定位踝关节中心的方法。位于胫骨和股骨中轴的额外关节允许在屈伸、内翻/外翻和旋转平面上发生变形。使用数字卡尺单元精确测量坐标，开发了一个软件程序，将这些局部坐标转换为实际腿部对线的测定。在手术的特定时间点，比较数字卡尺测量结果与无图像导航系统之间的信息。进行了重复的系列测量。在正常对线情况下，系统的平均误差在0.5度以内。在股骨和胫骨平面均异常对线的情况下，误差在1度以内。这是第一项旨在评估经过临床验证的导航系统准确性的研究。它证明了无图像导航系统在正常和异常腿部对线情况下的体外准确性。
