Tohoku University School of Medicine, Sendai, Japan.
Kamisugiyama Orthopaedic Clinic, Sendai, Japan.
Am J Sports Med. 2019 Mar;47(4):922-927. doi: 10.1177/0363546519825629.
The glenoid track concept has been widely used to assess the risk of instability caused by a bipolar lesion. The mean glenoid track width is reported to be 83% of the glenoid width. However, this width seems to be affected by the range of motion of the shoulder. By clarifying the relationship between the range of shoulder motion and the glenoid track width, a more precise determination of the glenoid track width for each individual could be possible.
To determine the relationship between the glenoid track width and the range of motion of healthy volunteers.
Descriptive laboratory study.
Magnetic resonance imaging was taken in 41 shoulders of 21 healthy volunteers (mean age, 32 years) with the arm in maximum horizontal extension, with the arm kept in 90° of abduction and 90° of external rotation. Three-dimensional surface bone models of the glenoid and the humerus were created with image analysis software. The distance from the anterior rim of the glenoid to the medial margin of the footprint of the rotator cuff tendon was defined as the glenoid track width. Active and passive ranges of shoulder motion were measured in the supine and sitting positions. The correlations between the glenoid track width and the ranges of shoulder motion were investigated with Pearson correlation coefficients. Intra- and interobserver reliabilities based on the intraclass correlation coefficient were also analyzed to assess the reliability of the glenoid track measurement.
The intra- and interobserver reliabilities for the glenoid track measurement were excellent (0.988 and 0.988, respectively). Among all the measurements, the glenoid track width and the active range of motion in horizontal extension in the sitting position showed the greatest correlation coefficient ( r = -0.623, P < .0001). A correlation between the glenoid track width and this angle was expressed as Y = -0.49 X + 90, where X is the horizontal extension angle (degrees) and Y is the glenoid track width (percentage of glenoid width).
The present data demonstrate that the greater the horizontal extension angle in abduction and external rotation, the smaller the glenoid track width. An individualized glenoid track width can be obtained by measuring the active horizontal extension angle with the arm in abduction and external rotation in the sitting position.
An individualized glenoid track width enables selection of a more precise surgical option by the on-track/off-track concept.
盂肱关节轨迹概念已被广泛用于评估由双极病变引起的不稳定风险。据报道，平均盂肱关节轨迹宽度为盂肱关节宽度的 83%。然而，这个宽度似乎受到肩部运动范围的影响。通过阐明肩部运动范围与盂肱关节轨迹宽度之间的关系，可以更精确地确定每个个体的盂肱关节轨迹宽度。
确定健康志愿者的盂肱关节轨迹宽度与运动范围之间的关系。
描述性实验室研究。
对 21 名健康志愿者（平均年龄 32 岁）的 41 个肩部进行磁共振成像检查，手臂处于最大水平伸展位，手臂保持 90°外展和 90°外旋。使用图像分析软件创建盂肱关节和肱骨头的三维表面骨模型。将盂肱关节前缘到肩袖肌腱的内侧缘的距离定义为盂肱关节轨迹宽度。在仰卧位和坐位测量肩部的主动和被动运动范围。使用 Pearson 相关系数研究盂肱关节轨迹宽度与肩部运动范围之间的相关性。还基于组内相关系数分析了内-间观察者可靠性，以评估盂肱关节轨迹测量的可靠性。
盂肱关节轨迹测量的内-间观察者可靠性均为优秀（0.988 和 0.988）。在所有测量中，盂肱关节轨迹宽度与坐位水平伸展时的主动运动范围显示出最大的相关系数（r = -0.623，P <.0001）。盂肱关节轨迹宽度与该角度之间的关系表示为 Y = -0.49 X + 90，其中 X 是水平伸展角度（度），Y 是盂肱关节轨迹宽度（盂肱关节宽度的百分比）。
本研究数据表明，外展和外旋时的水平伸展角度越大，盂肱关节轨迹宽度越小。通过在坐位外展和外旋时测量主动水平伸展角度，可以获得个体化的盂肱关节轨迹宽度。
个体化的盂肱关节轨迹宽度可以通过“轨迹内/轨迹外”概念选择更精确的手术方案。
