Department of Orthopaedic and Trauma Surgery, College of Medicine, Dentistry and Nursing, University of Dundee, TORT Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, UK.
J Shoulder Elbow Surg. 2012 May;21(5):612-7. doi: 10.1016/j.jse.2011.04.005. Epub 2011 Jul 23.
The anatomic neck of the humerus is used as a reference for the osteotomy in shoulder arthroplasty. Resection along the anterior portion of the cartilage/metaphyseal border is assumed to remove a cap of a sphere that can accurately be replaced with a spherical prosthetic implant oriented precisely to the original articular surface. The aim of this study was to determine the variability in retroversion of the cartilage/metaphyseal interface in the axial plane.
Surface topography data for 24 arms from deceased donors were collected by using a hand-held digitizer and a surface laser scanner. Data were combined into the same coordinate system and graphically presented. The humeral head was divided into 6 sections in the axial plane and the retroversion angle measured at each level with reference to the transepicondylar axis at the elbow.
The mean retroversion of the humeral head at the midpoint between the superior and inferior margins was 18.6°. The angle increased as the position of the measurement moved superiorly to 22.5°. In contrast, the retroversion angle reduced as the position of measurement moved more inferiorly to 14.3°.
The results suggest that the cartilage/metaphyseal interface is not circular encompassing a spherical cap of a sphere. Furthermore, there appears to be a clockwise torsion of the cartilage/metaphyseal interface about the transverse axis from its medial to lateral aspect.
The cartilage/metaphyseal interface shows a degree of variability that makes it an unreliable landmark to perform an osteotomy when the anterior aspect of the interface is used.
肱骨解剖颈被用作肩关节置换术中截骨的参考。假设沿着软骨/骺线的前部分切除一个球体的帽状结构，可以用精确定向于原始关节表面的球形假体植入物准确替换。本研究的目的是确定在轴平面上软骨/骺界面后倾的可变性。
通过使用手持数字化仪和表面激光扫描仪，收集了 24 个来自已故供体的手臂的表面形貌数据。将数据组合到同一坐标系中并进行图形化展示。在轴平面上将肱骨头分为 6 个部分，并在每个水平上测量相对于肘的髁间轴的后倾角度。
在上下缘之间中点的肱骨头的平均后倾为 18.6°。随着测量位置向顶部移动，角度增加到 22.5°。相比之下，随着测量位置向下移动，后倾角度减小到 14.3°。
结果表明，软骨/骺界面不是包含球体的球形帽的圆形。此外，软骨/骺界面似乎在从内侧到外侧的横轴上围绕顺时针方向扭转。
软骨/骺界面显示出一定程度的可变性，当使用界面的前侧进行截骨时，它成为不可靠的标志。
