Siston Robert A, Daub Aaron C, Giori Nicholas J, Goodman Stuart B, Delp Scott L
Mechanical Engineering Department, Stanford University, Stanford, CA 94305-5450, USA.
Clin Orthop Relat Res. 2005 Oct;439:129-35. doi: 10.1097/01.blo.0000170873.88306.56.
Accurate alignment of the mechanical axis of the limb is important to the success of a total knee arthroplasty. Although computer-assisted navigation systems can align implants more accurately than traditional mechanical guides, the ideal technique to determine the distal end point of the mechanical axis, the center of the ankle, is unknown. In this study, we evaluated the accuracy, precision, objectivity, and speed of five anatomic methods and two kinematic methods for estimating the ankle center in 11 healthy subjects. Magnetic resonance images were used to characterize the shape of the ankle and establish the true ankle center. The most accurate and precise anatomic method was establishing the midpoint of the most medial and most lateral aspects of the malleoli (4.5 +/- 4.1 mm lateral error; 2.7 +/- 4.5 mm posterior error). A biaxial model of the ankle (2.0 +/- 6.4 mm medial error; 0.3 +/- 7.6 mm anterior error) was the most accurate kinematic method. Establishing the midpoint of the most medial and most lateral aspects of the malleoli was an accurate, precise, objective, and fast method for establishing the center of the ankle.
肢体机械轴的精确对线对全膝关节置换术的成功至关重要。尽管计算机辅助导航系统比传统机械导向装置能更精确地对线植入物，但确定机械轴远端终点即踝关节中心的理想技术尚不清楚。在本研究中，我们评估了11名健康受试者中五种解剖学方法和两种运动学方法估计踝关节中心的准确性、精确性、客观性和速度。使用磁共振成像来表征踝关节的形状并确定真正的踝关节中心。最准确和精确的解剖学方法是确定内、外踝最内侧和最外侧方面的中点（外侧误差4.5±4.1毫米；后方误差2.7±4.5毫米）。踝关节双轴模型（内侧误差2.0±6.4毫米；前方误差0.3±7.6毫米）是最准确的运动学方法。确定内、外踝最内侧和最外侧方面的中点是一种准确、精确、客观且快速的确定踝关节中心的方法。
