Goodsam Orthopaedic Clinic, Cheongju, Korea.
Department of Orthopaedic Surgery, Chungbuk National University Hospital, Cheongju, Korea.
Korean J Radiol. 2019 Jun;20(6):931-938. doi: 10.3348/kjr.2018.0541.
To compare inferior capsular redundancy by using magnetic resonance arthrography (MRA) images in patients with multidirectional instability (MDI) of the shoulder and control subjects without instability and thereby develop a screening method to identify the presence of shoulder MDI.
The MRA images of patients with MDI of the shoulder (n = 65, 57 men, 8 women; mean age, 24.5 years; age range, 18-42 years) treated over an eight-year period were retrospectively reviewed; a control group (n = 65, 57 men, 8 women; mean age, 27.4 years; age range, 18-45 years) without instability was also selected. The inferior capsular redundancy was measured using a new method we named the glenocapsular (GC) ratio method. MRA images of both groups were randomly mixed together, and two orthopedic surgeon reviewers measured the cross-sectional areas (CSAs) and sagittal capsule-head ratios on oblique sagittal images, as well as the axial capsule-head ratios on axial images and GC ratios on oblique coronal images.
The CSAs and GC ratios were significantly higher in patients than in controls (both, < 0.001); however, the sagittal capsule-head ratios and axial capsule-head ratios were not significantly different ( = 0.317, = 0.053, respectively). In addition, GC ratios determined the presence of MDI more sensitively and specifically than did CSAs. A GC ratio of > 1.42 was found to be most suggestive of MDI of the shoulder, owing to its high sensitivity (92.3%) and specificity (89.2%).
GC ratio can be easily measured and used to accurately screen for MDI of the shoulder.
通过对比患有多向性肩关节不稳（MDI）患者和无肩关节不稳的对照组患者的磁共振关节造影（MRA）图像，评估下囊冗余程度，从而建立一种用于筛选肩关节 MDI 的方法。
回顾性分析了 65 例（57 名男性，8 名女性；平均年龄 24.5 岁；年龄范围 18-42 岁）接受治疗的 MDI 患者肩关节的 MRA 图像，随访时间 8 年；同时选择了 65 例（57 名男性，8 名女性；平均年龄 27.4 岁；年龄范围 18-45 岁）无肩关节不稳的患者作为对照组。使用我们命名的“肩盂肱（GC）比率法”测量下囊冗余程度。将两组的 MRA 图像随机混合，由两位骨科医生分别在斜矢状位图像上测量横截面积（CSA）和关节囊-头比值、在轴位图像上测量关节囊-头比值以及在斜冠状位图像上测量 GC 比值。
患者的 CSA 和 GC 比值均明显高于对照组（均<0.001）；但关节囊-头矢状比值和关节囊-头轴位比值无明显差异（=0.317，=0.053）。此外，GC 比值比 CSA 更能敏感和特异的确定 MDI 的存在。GC 比值>1.42 时，最有可能患有肩关节 MDI，因为其具有较高的敏感性（92.3%）和特异性（89.2%）。
GC 比值易于测量，可用于准确筛选肩关节 MDI。
