Model for in-vivo estimation of stiffness of tibiofemoral joint using MR imaging and FEM analysis

Abstract

Background Appropriate structural and material properties are essential for finite-element-modeling (FEM). In knee FEM, structural information could extract through 3D-imaging, but the individual subject’s tissue material properties are inaccessible. Purpose The current study's purpose was to develop a methodology to estimate the subject-specific stiffness of the tibiofemoral joint using finite-element-analysis (FEA) and MRI data of knee joint with and without load. Methods In this study, six Magnetic Resonance Imaging (MRI) datasets were acquired from 3 healthy volunteers with axially loaded and unloaded knee joint. The strain was computed from the tibiofemoral bone gap difference (ΔmBGFT) using the knee MR images with and without load. The knee FEM study was conducted using a subject-specific knee joint 3D-model and various soft-tissue stiffness values (1 to 50 MPa) to develop subject-specific stiffness versus strain models. Results Less than 1.02% absolute convergence error was observed during the simulation. Subject-specific combined stiffness of weight-bearing tibiofemoral soft-tissue was estimated with mean values as 2.40 ± 0.17 MPa. Intra-subject variability has been observed during the repeat scan in 3 subjects as 0.27, 0.12, and 0.15 MPa, respectively. All subject-specific stiffness-strain relationship data was fitted well with power function (R2 = 0.997). Conclusion The current study proposed a generalized mathematical model and a methodology to estimate subject-specific stiffness of the tibiofemoral joint for FEM analysis. Such a method might enhance the efficacy of FEM in implant design optimization and biomechanics for subject-specific studies. Trial registration The institutional ethics committee (IEC), Indian Institute of Technology, Delhi, India, approved the study on 20th September 2017, with reference number P-019; it was a pilot study, no clinical trail registration was recommended.

Device for Assessing Knee Joint Dynamics During Magnetic Resonance Imaging

“…A knee loading study with MRI to access the additional information and dynamic changes in weight‐bearing knee requires an MR‐safe knee axial loading arrangement. Various clinical applications were suggested in previous reports 22,24,28–31,39,40 . Therefore, the primary objective of the current study was to design and develop a portable and easy in use, axial loading knee joint device, which would be capable of addressing the limitation of previously reported devices 8,14–17 ; furthermore, the device has been tested for MR safety, the device induces artifact and change in image quality and the repeatability of the device performance.…”

“…Various clinical applications were suggested in previous reports. 22,24,[28][29][30][31]39,40 Therefore, the primary objective of the current study was to design and develop a portable and easy in use, axial loading knee joint device, which would be capable of addressing the limitation of previously reported devices 8,[14][15][16][17] ; furthermore, the device has been tested for MR safety, the device induces artifact and change in image quality and the repeatability of the device performance. The secondary objective of the current study was to observe changes in load-bearing tissue of the knee joint using the proposed loading device and conventional 3.0 T MRI.…”

How effective is proximal fibular osteotomy in redistributing joint pressures? Insights from an HTO comparative in-silico study

“…A total force of 750 N was exerted vertically on the proximal head of the femur to replicate the complete weight of an average adult weighing 75 kg [ 39 , 48 , 54 , 55 , 61 – 66 ].…”

“…Distal ends of both the tibia and fibula were fixed in all studied models [22,56,60], mimicking contact interactions with the ankle joint. A total force of 750 N was exerted vertically on the proximal head of the femur to replicate the complete weight of an average adult weighing 75 kg [39,48,54,55,[61][62][63][64][65][66].…”

How effective is proximal fibular osteotomy in redistributing joint pressures? Insights from an HTO comparative in-silico study

“…A total force of 750 N was exerted vertically on the proximal head of the femur to replicate the complete weight of an average adult weighing 75 kg [37,46,52,53,[59][60][61][62][63][64].…”