Department of Mechanical Engineering, The University of Western Ontario, London, ON, Canada; The Roth|McFarlane Hand and Upper Limb Centre, St. Joseph's Hospital, London, ON, Canada.
Department of Mechanical Engineering, The University of Western Ontario, London, ON, Canada; The Roth|McFarlane Hand and Upper Limb Centre, St. Joseph's Hospital, London, ON, Canada; Department of Surgery, The University of Western Ontario, London, ON, Canada; Department of Biomedical Engineering, The University of Western Ontario, London, ON, Canada.
J Shoulder Elbow Surg. 2018 Apr;27(4):650-658. doi: 10.1016/j.jse.2017.10.029. Epub 2017 Dec 29.
Shoulder arthroplasty evolution has resulted in the shortening of traditional stemmed humeral components. Newer stemless implants rely on structures that maintain fixation in the metaphyseal region of the proximal humerus. Whereas the overall morphology of the proximal humerus is well understood, the advent of stemless implants requires that additional geometric measures be assessed. This study's purpose was to introduce new anatomic measures to assist with the design of stemless implants.
Using computed tomography data from 98 subjects (nonarthritic [n = 41], B2 osteoarthritic [n = 26], and symmetric osteoarthritic [n = 31]), shifts in proximal canal direction, bounding diameters along the canal, and canal depth beneath the center of the humeral resection plane were quantified. Traditional articular aspect ratio terms (ie, resection diameter, humeral head height) were also quantified. All measures were reported relative to a humeral coordinate system relevant to stemless implants.
Humeral depth, gender, and osteoarthritis were found to have effects on the measured parameters. Of these factors, gender was the most prominent, as men presented with significantly larger canal diameters and depths than women did (P < .001). Osteoarthritis had less of a significant impact on results (P < .001), with the attributed differences in canal path direction and articular aspect ratio being small in absolute value. Canal diameter was found to change significantly as a function of depth beneath the resection plane (P < .001).
This work quantified 3 new morphologic terms relevant to proximal humerus stemless arthroplasty. Together, these outcome measures help define the spatial limits for stemless humeral arthroplasty in an implant-relevant coordinate system.
肩关节置换术的发展导致传统的带柄肱骨部件变短。新型无柄植入物依赖于维持肱骨近端干骺端固定的结构。虽然肱骨近端的整体形态已得到很好的理解，但无柄植入物的出现需要评估其他几何测量值。本研究的目的是引入新的解剖学测量值来辅助无柄植入物的设计。
使用来自 98 名受试者（非关节炎[ n = 41]，B2 骨关节炎[ n = 26]和对称骨关节炎[ n = 31]）的 CT 数据，量化了近端管腔方向的移位、管腔沿管腔的边界直径以及肱骨切除平面下中心处的管腔深度。还量化了传统的关节面比率术语（即，切除直径，肱骨头高度）。所有测量值均相对于与无柄植入物相关的肱骨坐标系进行报告。
发现肱骨深度、性别和骨关节炎对测量参数有影响。在这些因素中，性别是最主要的因素，男性的管腔直径和深度明显大于女性（ P < 0.001）。骨关节炎的影响较小（ P < 0.001），其对管腔路径方向和关节面比率的影响绝对值较小。发现管腔直径随切除平面下深度的变化显著（ P < 0.001）。
这项工作量化了与肱骨近端无柄关节置换术相关的 3 个新的形态学术语。这些结果衡量标准共同有助于在植入物相关坐标系中定义无柄肱骨关节置换术的空间限制。
