Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA.
Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA.
J Shoulder Elbow Surg. 2020 Nov;29(11):2229-2239. doi: 10.1016/j.jse.2019.12.035. Epub 2020 May 13.
The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not.
This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle.
In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001).
Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty.
本研究旨在确定（1）与金标准 CT 相比，MRI 能否准确测量肩峰形态；（2）能否在 MRI 上可靠测量；（3）是否存在肩袖撕裂（RCT）患者与无 RCT 或肩关节炎证据患者之间的差异；（4）与愈合的肩袖修复（RCR）患者与未愈合的患者之间的差异。
这是一项回顾性对比研究。我们在 MRI 上测量冠状位、轴位和矢状位肩峰倾斜度；肩峰宽度、肩峰前后覆盖度、盂肱关节面倾斜角和关节盂倾斜角。通过计算组内相关系数（ICC）确定准确性。为了确定可靠性，由 2 名观察者在 MRI 上进行相同的测量，并计算 ICC。我们比较了有全层 RCT 患者与>50 岁且无 RCT 或肩关节炎证据患者之间的这些测量值。然后，我们比较了 MRI 显示愈合的 RCR 患者与肩袖回缩患者之间的这些测量值。在这部分，我们仅包括了术前 MRI 和 RCR 术后至少 1 年的 MRI 的患者。只有术后 MRI 上没有肌腱缺损的患者才被认为是愈合的。在这些患者中，我们还进行了影像学测量关键肩角。
在 30 例具有 MRI 和 CT 的验证队列患者中，所有 ICC 均>0.86。在这些患者中，MRI 测量的组内观察者 ICC>0.53。在我们的 110 例 RCT 患者组中，肩峰宽度更大[平均差异（95%置信区间）=0.1（0，0.2）mm，P=0.012]，矢状位肩峰倾斜度明显较小[9°（5°-12°），P<0.001]，而在我们的 107 例对照组患者中。共纳入 110 例 RCR。术后 MRI 扫描在平均随访 24.2±15.8 个月时获得，显示 84 例（76%）患者的 RCR 愈合。除了肩峰宽度相差 0.2mm 且无临床意义外，愈合与任何测量形态特征之间均无关联。愈合修复患者的撕裂宽度（P<0.001）和回缩（P<0.001）均显著较小。
尽管 RCT 患者的肩峰更宽，但 0.1mm 的差异可能没有临床意义。肩袖撕裂患者的肩峰从后下到前上的斜率更大。这些发现使人们对由于原发性肩峰形态导致肩袖撕裂的肩峰下撞击提出质疑。RCR 后，肩峰形态、关键肩角和关节盂倾斜角与愈合无关。本研究不支持外侧肩峰成形术。
