Department of Engineering Mechanics, Nanling Campus, Jilin University, No, 5988 Renmin Street, Changchun 130025, People's Republic of China.
Biomed Eng Online. 2013 Dec 20;12:130. doi: 10.1186/1475-925X-12-130.
Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity.
The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements.
The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics.
It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better understand the mechanism of osteoarthritis and provides theoretical basis and computational method for the prevention and treatment of osteoarthritis. It can also serve as basis for further study on periprosthetic BMD changes after total knee arthroplasty, and provide a theoretical basis for optimization design of prosthesis.
骨骼可以通过调整其形态结构来适应力学环境的变化，即骨骼结构的变化与机械负荷有关。这意味着骨关节炎可能与膝关节畸形密切相关。本文旨在模拟不同力学环境下三维（3D）胫骨近端内部骨矿物质密度（BMD）的变化，并探讨力学环境与骨形态异常的关系。
对右胫骨近端进行 CT 扫描，在 Mimics 中重建 3D 胫骨近端模型，然后将其导入有限元软件 ANSYS 中建立 3D 有限元模型。采用定量骨重建理论结合有限元方法模拟正常年轻人 3D 胫骨近端内部结构，根据内侧胫骨平台关节接触力的变化模式，改变力学载荷，以模拟正常胫骨结构作为初始结构，模拟 6°外翻畸形老年人的 3D 胫骨近端内部结构。在胫骨近端选择 4 个感兴趣区域（ROI）进行定量分析 BMD，并与临床测量值进行比较。
模拟结果表明，正常膝关节 3D 胫骨近端的 BMD 分布与临床测量值一致，外翻膝关节的 BMD 分布与临床骨关节炎患者的测量值一致。
力学环境的改变是导致软骨下骨结构改变的主要原因，长期处于异常力学环境下可能导致骨关节炎。此外，本文采用的模拟方法可以更准确地模拟不同力学环境下 3D 胫骨近端的内部结构，有助于更好地理解骨关节炎的发病机制，为骨关节炎的预防和治疗提供理论依据和计算方法，也可为全膝关节置换术后假体周围 BMD 变化的进一步研究提供依据，为假体的优化设计提供理论依据。
