Muraki Takayuki, Yamamoto Nobuyuki, Sperling John W, Steinmann Scott P, Cofield Robert H, An Kai-Nan
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic, Rochester, MN, USA.
Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
J Shoulder Elbow Surg. 2017 May;26(5):861-869. doi: 10.1016/j.jse.2016.10.009. Epub 2017 Jan 11.
Patients with subacromial impingement were reported to show abnormal scapular positions during shoulder elevation. However, the relationship between the scapular positions and subacromial impingement is unclear. The purpose of this study was to biomechanically determine the effect of scapular position on subacromial contact behavior by using fresh frozen cadavers.
The peak contact pressure on the coracoacromial arch was measured with a flexible tactile force sensor in 9 fresh frozen cadaver shoulders. The measurement was performed during passive glenohumeral elevation in the scapular plane ranging from 30° to 75°. The scapular downward and internal rotations and anterior tilt were simulated by tilting the scapula in 5° increments up to 20°. The measurement was also performed with combination of scapular downward and internal rotations and anterior tilt positions.
The peak contact pressure decreased linearly with anterior tilt, and a significant difference between neutral scapular position (1.06 ± 0.89 MPa) and anterior tilt by 20° (0.46 ± 0.18 MPa) was observed (P < .05). However, the scapular positioning in the other directions did not change the peak contact pressure significantly. Furthermore, any combination of abnormal scapular positions did not affect peak contact pressure significantly.
Scapular anterior tilt decreased peak contact pressure during passive shoulder elevation. In addition, scapular downward and internal rotations had little effect on peak contact pressure. The abnormal scapular motion reported in previous studies might not be directly related to symptoms caused by subacromial impingement.
据报道，肩峰下撞击综合征患者在肩关节上举过程中表现出肩胛骨位置异常。然而，肩胛骨位置与肩峰下撞击之间的关系尚不清楚。本研究的目的是通过使用新鲜冷冻尸体，从生物力学角度确定肩胛骨位置对肩峰下接触行为的影响。
使用柔性触觉力传感器测量9个新鲜冷冻尸体肩关节在喙肩弓上的峰值接触压力。测量在肩胛平面内被动肱盂关节上举30°至75°的过程中进行。通过将肩胛骨以5°的增量倾斜至20°来模拟肩胛骨向下和内旋以及前倾。测量也在肩胛骨向下和内旋以及前倾位置的组合下进行。
峰值接触压力随着前倾呈线性下降，观察到肩胛骨中立位（1.06±0.89MPa）与前倾20°（0.46±0.18MPa）之间存在显著差异（P＜0.05）。然而，肩胛骨在其他方向的定位并未显著改变峰值接触压力。此外，肩胛骨异常位置的任何组合均未对峰值接触压力产生显著影响。
肩胛骨前倾在被动肩关节上举过程中降低了峰值接触压力。此外，肩胛骨向下和内旋对峰值接触压力影响较小。先前研究中报道的肩胛骨异常运动可能与肩峰下撞击引起的症状没有直接关系。
