Meskers C G, van der Helm F C, Rozendaal L A, Rozing P M
Orthopaedic Laboratory, Department of Orthopaedic Surgery, University Hospital, Leiden, The Netherlands.
J Biomech. 1998 Jan;31(1):93-6. doi: 10.1016/s0021-9290(97)00101-2.
In this paper, a method is described for in vivo prediction of the glenohumeral joint rotation center (GH-r), necessary for the construction of a humerus local coordinate system in shoulder kinematic studies. The three-dimensional positions of five scapula bony landmarks as well as a large number of data points on the surface of the glenoid and humeral head were collected at 36 sets of cadaver scapulae and adjacent humeri. The position of GH-r in each scapula was estimated by mathematically fitting spheres to the glenoid and humeral head. GH-r prediction from scapula geometry parameters by linear regression resulted in a RMSE between measured and predicted GH-r of 2.32 mm for the x-coordinate, 2.69 mm for the y-coordinate and 3.04 mm for the z-coordinate. Application in vivo revealed a random humerus orientation error due to measurement inaccuracies of 1.35, 0.29 and 1.26 degrees standard deviation per rotation angle. The estimated total humerus orientation error including the offset error due to the regression model inaccuracy was 2.86, 0.84 and 2.69 degrees standard deviation. As these errors were about 15 and 20% of, respectively, the intra- and inter-subject variability of the humerus orientations measured, it is concluded that the method described in this paper allows for an adequate construction of a humerus local coordinate system.
本文描述了一种用于体内预测盂肱关节旋转中心（GH-r）的方法，这是肩部运动学研究中构建肱骨局部坐标系所必需的。在36组尸体肩胛骨及相邻肱骨上，收集了五个肩胛骨骨性标志的三维位置以及肩胛盂和肱骨头表面的大量数据点。通过将球体数学拟合到肩胛盂和肱骨头来估计每个肩胛骨中GH-r的位置。通过线性回归从肩胛骨几何参数预测GH-r，测得的GH-r与预测的GH-r之间的均方根误差在x坐标上为2.32毫米，y坐标上为2.69毫米，z坐标上为3.04毫米。体内应用显示，由于测量不准确，每个旋转角度的肱骨定向随机误差标准差为1.35、0.29和1.26度。包括回归模型不准确导致的偏移误差在内的估计总肱骨定向误差标准差为2.86、0.84和2.69度。由于这些误差分别约为所测肱骨定向的受试者内和受试者间变异性的15%和20%，因此得出结论，本文所述方法能够充分构建肱骨局部坐标系。
