足弓第2与第5跖列的肌骨系有限元模型及其临床意义

目的：建立足部内侧纵弓第2跖列与外侧纵弓第5跖列的肌骨系统有限元模型,为研究跖骨应力性骨折与相关足痛症提供生物力学工具。方法：采用中国虚拟人“女性1号”CT图像和MRI图像;应用非线性有限元方法进行生物力学分析。结果：构建了包含皮质骨、松质骨、软骨、韧带、足底腱膜、肌腱、固有肌、脂肪垫、骨髓腔与骨髓窦等10种组织的第2、第5跖列的有限元模型。足弓直立时,最大von Mises应力／应变位于第2、第5跖骨骨干与基底。各种足底软组织中,足底腱膜承担着最大张拉应力,其次为足底长韧带,足底固有肌张拉应力最小。结论：有限元预测的应力应变为研究跖骨应力性骨折,足底腱膜炎引起的慢性跟骨痛,以及足弓塌陷的发生机制提供了生物力学依据。

Clinical significations of finite element models of the second ray and the fifth ray of the musculoskeletal plantar arch

Objective: To develop anatomically detailed finite element models of the second ray and the fifth ray of the musculoskeletal plantar arches, which may provide a biomechanical tool for investigating metatarsal stress fractures and painful foot syndrome. Methods: CT and MRI images of the foot of Virtual Chinese Human "female No. 1" were adopted, and the finite element method incorporating geometric and material nonlinearities was used. Results: Musculoskeletal finite element models of the second ray and the fifth ray were developed, which comprised of 10 kind of tissues. During balanced standing, the maximum von Mises stresses/strains were predicted at the second and the fifth metatarsal. Among plantar soft tissues, relative high tensions were burdened by plantar fascia, followed by long plantar ligament. The minimum tensions occurred in plantar intrinsic muscles. Conclusions: The finite element predictions contribute to establish biomechanical rationale for the etiology of metatarsal stress fractures, chronic heel pain ignited by plantar fasciitis, and the collapse of foot arch.