Hsu Yi-Chih, Pan Ru-Yu, Shih Yen-Yu I, Lee Meei-Shyuan, Huang Guo-Shu
Department of Radiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan, R.O.C.
Acta Radiol. 2010 Apr;51(3):302-8. doi: 10.3109/02841850903524421.
Redundancy of the capsule has been considered to be the main pathologic condition responsible for atraumatic posteroinferior multidirectional shoulder instability; however, there is a paucity of measurements providing quantitative diagnosis.
To determine the significance of superior-capsular elongation and its relevance to atraumatic posteroinferior multidirectional shoulder instability at magnetic resonance (MR) arthrography.
MR arthrography was performed in 21 patients with atraumatic posteroinferior multidirectional shoulder instability and 21 patients without shoulder instability. One observer made the measurements in duplicate and was blinded to the two groups. The superior-capsular measurements (linear distance and cross-sectional area) under the supraspinatus tendon, and the rotator interval were determined on MR arthrography and evaluated for each of the two groups.
For the superior-capsular measurements, the linear distance under the supraspinatus tendon was significantly longer in patients with atraumatic posteroinferior multidirectional shoulder instability than in control subjects (P<0.001). The cross-sectional area under the supraspinatus tendon, and the rotator interval were significantly increased in patients with atraumatic posteroinferior multidirectional shoulder instability compared to control subjects (P<0.001 and P=0.01, respectively). Linear distance greater than 1.6 mm under the supraspinatus tendon had a specificity of 95% and a sensitivity of 90% for diagnosing atraumatic posteroinferior multidirectional shoulder instability. Cross-sectional area under the supraspinatus tendon greater than 0.3 cm(2), or an area under the rotator interval greater than 1.4 cm(2) had a specificity of more than 80% and a sensitivity of 90%.
The superior-capsular elongation as well as its diagnostic criteria of measurements by MR arthrography revealed in the present study could serve as references for diagnosing atraumatic posteroinferior shoulder instability and offer insight into the spectrum of imaging findings corresponding to the pathologies encountered at clinical presentation.
关节囊冗余被认为是导致非创伤性后下方向多向性肩关节不稳的主要病理状况；然而，缺乏提供定量诊断的测量方法。
确定上盂肱韧带延长在磁共振关节造影（MR关节造影）中的意义及其与非创伤性后下方向多向性肩关节不稳的相关性。
对21例非创伤性后下方向多向性肩关节不稳患者和21例无肩关节不稳患者进行MR关节造影。由一名观察者进行两次测量，且对两组情况不知情。在MR关节造影上确定冈上肌腱下方的上盂肱韧带测量值（线性距离和横截面积）以及旋转间隙，并对两组分别进行评估。
对于上盂肱韧带测量，非创伤性后下方向多向性肩关节不稳患者冈上肌腱下方的线性距离显著长于对照组（P<0.001）。与对照组相比，非创伤性后下方向多向性肩关节不稳患者冈上肌腱下方的横截面积以及旋转间隙显著增大（分别为P<0.001和P=0.01）。冈上肌腱下方线性距离大于1.6 mm对诊断非创伤性后下方向多向性肩关节不稳的特异性为95%，敏感性为90%。冈上肌腱下方横截面积大于0.3 cm²或旋转间隙面积大于1.4 cm²的特异性超过80%，敏感性为90%。
本研究中揭示的上盂肱韧带延长及其MR关节造影测量诊断标准可作为诊断非创伤性后下方向肩关节不稳的参考，并有助于深入了解与临床表现中所遇病理状况相对应的影像学表现范围。
