Assessment of stress distribution in ankle joint: simultaneous application of experimental and finite element methods

Abstract

Abstract:The goal of this study was to determine stress distribution in ankle joint by correlating with the strain distribution and its trend around tibia adjacent to the joint. Using an in-house device, an ankle from a cadaver was kept stable and loaded in various positions: neutral, dorsiflexion, plantar flexion, inversion and eversion. A total of six strain gauges were mounted around the shaft of the tibia, near the tibiotalar joint. This arrangement allowed us to measure deformations in the shaft of tibia. Patient-specific ankle joint geometry was generated from computed tomography data. The finite element model (FEM) of the ankle was validated using the experimental data logged by the strain gauges, and used for obtaining stress on the joint surface. A strong correlation was observed between the FEM and experimentally measured strains in magnitude (R = 0.94, P = 0.008), consequently stress distribution over the joint surface was obtained. 46A. Chitsazan et al.

An extended discrete element method for the estimation of contact pressure at the ankle joint during stance phase

“…The difficulties in estimating the ankle contact pressure experimentally can be partially overcome by the use of in-silico models which simulate the contact of cartilage layers within the joints. Finite Element Analysis (FEA) has been widely used for the investigation of the joint contact pressure on subject-specific geometries of different joints, and researchers have tested and validated its predictions at the hip 12,13 , at the knee 14 , and at the ankle 15 . Hyperelastic 16 or multiphasic 17 descriptions of the cartilage can be treated within the framework of FEA.…”

“…Finite Element Analysis (FEA) has been widely used for the investigation of the joint contact pressure on subject-specific geometries of different joints, and researchers have tested and validated its predictions at the hip, 12 , 13 at the knee, 14 and at the ankle. 15 Hyperelastic 16 or multiphasic 17 descriptions of the cartilage can be treated within the framework of FEA. Numerical convergence problems and long computational time are however a common obstacle and they can be exacerbated when dealing with nonlinear materials and complex geometries.…”

Total ankle replacement along with subtalar joint arthrodesis: In‐vitro and in‐silico biomechanical investigations

“…The outcomes of the validated FE models complement the proposed experimental setup in the study of TAR or FTAR preference by providing stress distribution patterns on interfaces and even in internal regions of the simulated parts, for example, prosthesis, polyethylene compartment and bones. 19,29,35 Assuming that stress shielding and uneven wearing patterns are two major factors for prosthesis loosening and dislocation, 16,36 then a more uniform stress pattern (see Figures 6-9) will be highly desirable for increasing the longevity and reliability of the joint replacement procedures. 19,37 Thus, the disadvantage of small reduction in the neighboring joints' movement, due to the applied STJ fusion, can be well compromised with an increased longevity of the replaced joint.…”

“…Therefore, any additional intervention that gives rise to more monotonic stress patterns in the prosthesis and its neighboring bones can likely increase its longevity. It was found that there is a more uniform stress distribution in fused STJ, compared with the normal one 19 . Moreover, the asymmetric stress distribution in the tibial component of the prosthesis is reported in the literature with higher stresses in the lateral side 20,21 .…”

“…The compression test started with a 50 N pre‐loading to make a precise alignment of the sample in the fixture, then a maximum load of 1000 N was applied in the longitudinal direction on the tibia (Figure 3). This compressive force resembles the ankle joint's load at the mid‐stance phase of the gait cycle, 16,19 which in this phase of the gait cycle, calcaneus and adjacent bones were completely constrained by the ground. Moreover, since fibula does not play a significant role in the load‐carrying process, 7,33 its load‐bearing contribution was disregarded here.…”