Daalder Matt A, Venne Gabriel, Sharma Varun, Rainbow Michael, Bryant Timothy, Bicknell Ryan T
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.
Department of Surgery, Queen's University, Kingston, ON, Canada.
JSES Open Access. 2018 Aug 1;2(3):174-181. doi: 10.1016/j.jses.2018.06.002. eCollection 2018 Oct.
How trabecular bone density varies within the scapula and how this may lead to more optimal reverse shoulder arthroplasty (RSA) screw placement has not been addressed in the scientific literature. The 3 columns of trabecular bone within the scapula adjacent to the glenoid fossa, one extending through the lateral border, a second into the base of the coracoid process, and a third extending into the spine of the scapula, were hypothesized to be of relatively similar density.
Two-dimensional axial computed tomography (CT) images of 19 fresh frozen cadaver specimens were obtained. Digital Imaging and Communications in Medicine (DICOM; National Electrical Manufacturers Association, Rosslyn, VA, USA) image files of the CT scanned scapulae were imported into Mimics 17.0 Materialise Software (Leuven, Belgium) for segmentation and 3-dimensional digital model generation. To determine the distribution of trabecular bone density, Hounsfield unit (HU) values in the scapulae gray value files obtained from Mimics were filtered to remove any cortical bone. HU values of 650 define the corticocancellous interface in CT image data and were considered to be cortical bone. Analyses of variance with post hoc Bonferroni tests were used to determine statistical differences between the intra- and inter-regions of bone density comparisons.
The base of the coracoid process was statistically significantly less dense than the spine and the lateral border of the scapulae examined ( < .05).
DISCUSSION/CONCLUSION: The higher-quality bone in the spine and lateral border, compared with the coracoid regions, may provide better bone purchase for screws when fixing the glenoid baseplate in RSA.
肩胛内小梁骨密度如何变化，以及这如何导致更优化的反肩关节置换术（RSA）螺钉置入，科学文献中尚未涉及。肩胛盂窝附近肩胛内的三列小梁骨，一列穿过外侧缘，第二列进入喙突基底部，第三列延伸至肩胛冈，被假设密度相对相似。
获取19个新鲜冷冻尸体标本的二维轴向计算机断层扫描（CT）图像。将CT扫描肩胛的医学数字成像和通信（DICOM；美国弗吉尼亚州罗斯林市国家电气制造商协会）图像文件导入Mimics 17.0 Materialise软件（比利时鲁汶）进行分割和三维数字模型生成。为确定小梁骨密度分布，对从Mimics获得的肩胛灰度值文件中的Hounsfield单位（HU）值进行过滤，以去除任何皮质骨。HU值650定义CT图像数据中的皮质骨松质界面，被视为皮质骨。采用方差分析及事后Bonferroni检验确定骨密度比较的区域内和区域间的统计学差异。
喙突基底部的密度在统计学上显著低于所检查肩胛的肩胛冈和外侧缘（<0.05）。
讨论/结论：与喙突区域相比，肩胛冈和外侧缘的骨质质量更高，在RSA中固定肩胛盂基板时，可能为螺钉提供更好的骨质锚固。
