Faculty of Civil Engineering and Transportation, Department of Civil Engineering, University of Isfahan, Isfahan, Iran.
Division of Orthopaedic Surgery, Department of Surgery, University of Alberta, Edmonton, AB, Canada.
J Anat. 2022 Feb;240(2):305-322. doi: 10.1111/joa.13552. Epub 2021 Sep 21.
Statistical data pertaining to anatomic variations of the human talus contain valuable information for advances in biological anthropology, diagnosis of the talar pathologies, and designing talar prostheses. A statistical shape model (SSM) can be a powerful data analysis tool for the anatomic variations of the talus. The main concern in constructing an SSM for the talus is establishing the true geometric correspondence between the talar geometries. The true correspondence complies with biological and/or mathematical homologies on the talar surfaces. In this study, we proposed a semi-automatic approach to establish a dense correspondence between talar surfaces discretized by triangular meshes. Through our approach, homologous salient surface features in the form of crest lines were detected on 49 talar surfaces. Then, the point-wise correspondence information of the crest lines was recruited to create posterior Gaussian process morphable models that non-rigidly registered the talar meshes and consequently established inter-mesh dense correspondence. The resultant correspondence perceptually represented the true correspondence as per our visual assessments. Having established the correspondence, we computed the mean shape using full generalized Procrustes analysis and constructed an SSM by means of principal component analysis. Anatomical variations and the mean shape of the talus were predicted by the SSM. As a clinically related application, we considered the mean shape and investigated the feasibility of designing universal talar prostheses. Our results suggest that the mean shape of (the shapes of) tali can be used as a scalable shape template for designing universal talar prostheses.
有关人类距骨解剖变异的统计数据为生物人类学的进展、距骨病变的诊断和距骨假体的设计提供了有价值的信息。统计形状模型 (SSM) 可以成为距骨解剖变异的强大数据分析工具。构建距骨 SSM 的主要关注点是在距骨几何形状之间建立真实的几何对应关系。真实的对应关系符合距骨表面的生物学和/或数学同形性。在这项研究中，我们提出了一种半自动方法来建立离散三角网格距骨表面之间的密集对应关系。通过我们的方法，在 49 个距骨表面上检测到了以脊线形式存在的同源显著表面特征。然后，招募脊线的逐点对应信息来创建后高斯过程可变形模型，该模型非刚性地注册距骨网格，并因此建立了网格间密集对应关系。所得对应关系根据我们的视觉评估感知地表示真实对应关系。建立对应关系后，我们使用完全广义 Procrustes 分析计算平均形状，并通过主成分分析构建 SSM。使用 SSM 预测距骨的解剖变异和平均形状。作为与临床相关的应用，我们考虑了平均形状并研究了设计通用距骨假体的可行性。我们的结果表明，（各）跟骨的平均形状可用作设计通用距骨假体的可扩展形状模板。
