Ludewig Paula M, Hassett Daniel R, Laprade Robert F, Camargo Paula R, Braman Jonathan P
Program in Physical Therapy, Department of Physical Medicine and Rehabilitation, The University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA.
Clin Biomech (Bristol). 2010 Jun;25(5):415-21. doi: 10.1016/j.clinbiomech.2010.01.015. Epub 2010 Feb 24.
Our purposes were to compare between the original and current recommended standard methods of three-dimensional scapular rotation descriptions and to examine the prevalence of gimbal-lock for scapular motion during scapular plane abduction. Additionally we compared these standards to an alternative method and a glenoid based description.
Eleven asymptomatic subjects were studied using electromagnetic sensors secured to bone-fixed pins in the scapula and humerus during two repetitions of scapular plane abduction. Anatomical landmarks defined scapular axes. Scapular angular data were analyzed at humerothoracic elevation angles from initial to maximum elevation. Repeated measures ANOVAs were performed for each variable with a significance level of P<0.05. An anatomical model was used to compare the standards to the alternative and glenoid methods.
For scapular upward rotation and tilting, larger differences occurred between standards at higher angles of elevation. The current standard measured 12.4 degrees less upward rotation and 6.1 degrees greater posterior tilting at maximum elevation as compared to the original. The current standard measured 11.6 degrees less scapular internal rotation across all elevation angles. Using the original landmarks, six subjects attained a mean end-range humerothoracic elevation of 147.4 degrees (SD 12.1 degrees ), with a mean end-range scapular upward rotation of 54.4 degrees . The alternative method was more closely aligned to the glenoid method than the current standard.
Significant differences were found between the two standards. The current standard interprets the same scapular motion with less internal rotation and upward rotation, and more posterior tilting than the original. No subjects reached upward rotation positions nearing gimbal-lock. Axis orientations also affect clinical interpretation. The alternative method appears worthy of further consideration as shoulder kinematic measurement further evolves.
我们的目的是比较三维肩胛旋转描述的原始推荐标准方法和当前推荐标准方法，并研究肩胛平面外展期间肩胛运动中万向节锁定的发生率。此外，我们将这些标准与一种替代方法和基于肩胛盂的描述进行了比较。
在肩胛平面外展的两次重复过程中，使用固定在肩胛骨和肱骨骨固定针上的电磁传感器对11名无症状受试者进行了研究。解剖标志定义了肩胛轴。在从初始抬高到最大抬高的肱骨胸廓抬高角度下分析肩胛角数据。对每个变量进行重复测量方差分析，显著性水平为P<0.05。使用解剖模型将标准与替代方法和肩胛盂方法进行比较。
对于肩胛向上旋转和倾斜，在较高抬高角度时标准之间出现了更大的差异。与原始标准相比，当前标准在最大抬高时测量的向上旋转少12.4度，后倾大6.1度。在所有抬高角度下，当前标准测量的肩胛内旋少11.6度。使用原始标志，6名受试者的肱骨胸廓平均终末抬高为147.4度（标准差12.1度），肩胛平均终末向上旋转为54.4度。替代方法比当前标准更接近肩胛盂方法。
两种标准之间存在显著差异。当前标准对相同肩胛运动的解释是内旋和向上旋转较少，后倾比原始标准更多。没有受试者达到接近万向节锁定的向上旋转位置。轴的方向也会影响临床解释。随着肩部运动学测量的进一步发展，替代方法似乎值得进一步考虑。
