Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA.
Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA.
Anat Rec (Hoboken). 2021 Mar;304(3):507-517. doi: 10.1002/ar.24479. Epub 2020 Aug 3.
Bone resorption caused by stress shielding and insufficient bone-implant contact continues to be problematic for orthopedic endoprostheses that utilize osseointegration (OI) for skeletal fixation. Morphologic analyses have helped combat this issue by defining anatomic parameters to optimize endoprosthesis loading by maximizing bone-implant contact. These studies have not typically included diaphyseal medullary morphology, as this region is not pertinent to total joint replacement. To the contrary, percutaneous OI endoprostheses for prosthetic limb attachment are placed in the diaphysis of the long bone. This study examined the cortical and medullary morphology of 116 fresh-frozen human cadaveric tibia using computed tomography. Anatomic landmarks were selected and custom MATLAB scripts were used to analyze the cross-sectional cortical and medullary morphology normalized to biomechanical length (BML). BML measured the distance between the tibial plateau and the tibial plafond. Properties such as cortical thickness, medullary diameter, and circularity of the medullary canal were quantified. We tested the influence of sex and laterality on morphology, and examined variations along the length of the bone. Results showed that while both sex and laterality impacted the location of anatomic landmarks, only sex influenced cross-sectional morphology. Overall, morphology significantly affected shape along the length of the bone for all examined properties except medullary circularity. This analysis found that distal to 35% BML, the canal is conducive to a circular implant, with medullary diameter ranging from 13 to 32 mm between 20 and 80% BML. A large size range is necessary for sufficient implant contact in order to accommodate residual limb length after amputation.
由应力遮挡和骨-植入物接触不足引起的骨吸收仍然是利用骨整合（OI）进行骨骼固定的骨科内假体的一个问题。形态分析通过定义解剖参数来帮助解决这个问题，这些参数通过最大限度地增加骨-植入物接触来优化内假体的加载。这些研究通常不包括骨干髓腔形态，因为该区域与全关节置换无关。相反，用于假肢附着的经皮 OI 内假体放置在长骨的骨干中。本研究使用计算机断层扫描检查了 116 个新鲜冷冻的人体尸体胫骨的皮质和髓腔形态。选择解剖标志，并使用定制的 MATLAB 脚本分析归一化到生物力学长度（BML）的横截面皮质和髓腔形态。BML 测量胫骨平台和距骨平台之间的距离。量化了皮质厚度、髓腔直径和髓腔管的圆度等特性。我们测试了性别和侧别对形态的影响，并检查了沿骨长度的变化。结果表明，虽然性别和侧别都影响解剖标志的位置，但只有性别影响横截面形态。总体而言，除了髓腔圆度外，形态对所有检查特性的骨骼长度上的形状都有显著影响。该分析发现，在 BML 的 35%远端，管腔有利于圆形植入物，在 20%至 80%BML 之间，髓腔直径在 13 至 32mm 之间。为了适应截肢后残肢的长度，需要有足够的植入物接触来保证大的尺寸范围。
