Sieberer Johannes M, Cobo Michael, Rancu Albert L, LaMonica Julia, Brennan Kelsey, Copes Lynn E, Tommasini Steven M, Wiznia Daniel H, Lattanza Lisa L
School of Medicine - Orthopaedics & Rehabilitation, Yale University, New Haven, CT, USA.
School of Engineering and Applied Science, Mechanical Engineering and Material Science, Yale University, New Haven, CT, USA.
JSES Int. 2025 May 21;9(4):1428-1435. doi: 10.1016/j.jseint.2025.04.026. eCollection 2025 Jul.
The proximal radius (PR) spans from the radial head (RH) to the bicipital tuberosity. Numerous studies have described this morphology. However, much of the existing work oversimplifies the morphology; for example, modeling the radial neck and/or tuberosity as cylinders, excluding the intramedullary canal (IC) from analysis, and basing models on two-dimensional imaging. The IC is important for radial arthroplasty implant stem selection. The purpose of this study is to quantify the morphology of the PR with a focus on the IC, utilizing the analysis of 3-dimensional models. We stratify the study population into age, sex, and height groups to capture the variance expected in the general population. We hypothesize that IC morphology differs significantly between age, sex, and height groups.
One hundred fifty-one three-dimensional models of the PR and the corresponding ICs were created from CT scans of adult females and males with average height, divided into 3 equally sized age groups (25-30, 40-45, and 60-65 years), and adult females and males of short and tall built. The cross-sections of the first 60 mm of each PR shaft distal to the RH were automatically fitted with ellipses encompassing the external proximal radius (EPR) and the IC at 0.1 mm intervals. From this dataset, we quantified anatomical features relevant for RH arthroplasty, describing the PR and its IC.
Females had a smaller and narrower geometry. The PR morphology changed with age and patient height. The PR is eccentric, with the IC being significantly more eccentric.
This study finds a wide range in positioning and width of specific anatomical features of the radius relevant to RH arthroplasty implant sizing, which might impact future development of RH implant stems. Furthermore, we found differences related to sex, age, and height of the patient. Both the PR and its IC are eccentric.
近端桡骨（PR）从桡骨头（RH）延伸至肱二头肌结节。众多研究已描述了这种形态。然而，现有许多工作将这种形态过度简化；例如，将桡骨颈和/或结节建模为圆柱体，在分析中排除髓内管（IC），且基于二维成像构建模型。髓内管对于桡骨置换植入物柄的选择很重要。本研究的目的是利用三维模型分析，重点关注髓内管，对近端桡骨的形态进行量化。我们将研究人群按年龄、性别和身高分组，以捕捉一般人群中预期的差异。我们假设髓内管形态在年龄、性别和身高组之间存在显著差异。
从成年女性和男性的CT扫描中创建了151个近端桡骨及其相应髓内管的三维模型，这些成年女性和男性平均身高，分为3个等规模的年龄组（25 - 30岁、40 - 45岁和60 - 65岁），以及身材矮小和高大的成年女性和男性。在每个桡骨头远端60毫米的桡骨干的横截面上，以0.1毫米的间隔自动拟合包含近端桡骨外部（EPR）和髓内管的椭圆。从该数据集中，我们量化了与桡骨头置换相关的解剖特征，描述了近端桡骨及其髓内管。
女性的几何形状更小且更窄。近端桡骨的形态随年龄和患者身高而变化。近端桡骨是偏心的，髓内管的偏心程度明显更高。
本研究发现与桡骨头置换植入物尺寸相关的桡骨特定解剖特征在定位和宽度上存在广泛差异，这可能会影响未来桡骨头植入物柄的开发。此外，我们发现了与患者性别、年龄和身高相关的差异。近端桡骨及其髓内管都是偏心的。
