Department of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, 82, Gumi-Ro 173 Beon-Gil, Bundang-Gu, Seongnam-Si, Gyeonggi-Do, Republic of Korea.
Department of Orthopaedic Surgery, Kyung Hee University College of Medicine, Kyung Hee University Medical Center, 23, Kyungheedae-ro, Seoul, Dongdaemun-gu, Republic of Korea.
Int Orthop. 2021 Dec;45(12):3171-3177. doi: 10.1007/s00264-021-05235-7. Epub 2021 Oct 8.
Conventionally, the central structure of the baseplate is inserted through the point where the vertical and horizontal axes of the glenoid intersect (conventional insertion site (CIS)). However, there is scanty theoretical evidence that CIS has the optimal bone stock. We evaluated the optimal insertion site for the glenoid baseplate through the three-dimensional volumetric measurement of the glenoid bone stock.
Pre-operative computed tomography (CT) images of 30 consecutive reverse total shoulder arthroplasty procedures were analyzed. Three-dimensional image processing software was used to reconstruct CT and volumetrically measure the glenoid bone stock according to the simulated central peg. A simulated central peg was inserted to the medial pole of the scapula from 49 points determined along with the intersect point of the vertical and horizontal axes of the glenoid CIS at 2-mm intervals. The overlapped volume between the simulated central peg and glenoid vault, representing the amount of glenoid bone stock along the passage of the central peg, was then automatically calculated.
The depth of the glenoid vault was 25.5 ± 3.0 mm (range, 19.3-31.5), and the mean overlapped volume between the simulated central peg and the glenoid vault was 623.0 ± 185.8 ml. The optimal insertion site for the bony purchase of the central peg was 2 mm inferior and posterior from the CIS (765.3 ± 157.5).
The optimal insertion site of the baseplate is located slightly inferiorly and posteriorly to the CIS. This anatomical information may be used as a reference to determine the optimal insertion site of the baseplate according to an implant of a surgeon's choice.
传统上，基板的中心结构通过肩胛盂的垂直轴和水平轴相交的点插入（传统插入点（CIS））。然而，几乎没有理论证据表明 CIS 具有最佳的骨量。我们通过对肩胛盂骨量的三维容积测量来评估基板的最佳插入点。
分析了 30 例连续的反向全肩关节置换术的术前计算机断层扫描（CT）图像。使用三维图像处理软件根据模拟中央钉重建 CT 并对肩胛盂骨量进行容积测量。模拟中央钉从 CIS 肩胛盂垂直和水平轴交点以 2mm 的间隔沿肩胛盂内侧极插入 49 个点。然后自动计算模拟中央钉和肩胛盂穹窿之间的重叠体积，该体积代表中央钉通过时的肩胛盂骨量。
肩胛盂穹窿的深度为 25.5±3.0mm（范围为 19.3-31.5），模拟中央钉和肩胛盂穹窿之间的重叠体积平均值为 623.0±185.8ml。中央钉骨固定的最佳插入点位于 CIS 下方 2mm 且后方（765.3±157.5）。
基板的最佳插入点略低于 CIS 且位于其后。该解剖学信息可用于根据外科医生选择的植入物来确定基板的最佳插入点。
