Finite Element Analysis of Elbow Joint Stability by Different Flexion Angles of the Annular Ligament

Abstract

To investigate the biomechanical effects of different flexion angles of the annular ligament on elbow joint stability. Methods: Left elbow CT and MRI scans were chosen from a healthy volunteer, according to a previous research model. A cartilage and ligament model was constructed with SolidWorks software according to the MRI results to simulate the annular ligament during normal, loosen, and rupture conditions at different buckling angles (0,30, 60, 90, 120). In 15 elbow models, boundary conditions were set according to the literature. The different elbow 3D finite element models were imported into ABAQUS software to calculate and analyze the load, contact area, contact stress and stress of the medial collateral ligament of the olecranon cartilage. Results: 1. According to the analysis results, olecranon cartilage stress values when the annular ligament under different conditions(normal、loosened、ruptured)with elbow extension, were 2.1 ± 0.18, 2.4 ± 0.75, and 2.9 ± 0.94 MPa. As the buckling angle increased, the stress value decreased; with 120 degrees of elbow flexion, the minimum stress values were 0.9 ± 0.12, 1.1 ± 0.38, and 1.2 ± 0.29 MPa. 2. When the contact surface of the olecranon cartilage was flexed from 0 to 30 degrees, the olecranon cartilage contact area significantly increased, reaching a maximum value of 254±5.35 mm, and then the contact area gradually decreased, reaching a minimum value of 176±2.62 mm when the elbow joint was flexed to 120 degrees. The results when the annular ligament was loosened and ruptured were different from those of the normal annular ligament. The maximum values were 283±4.74and 312±5.49mm at 60 degrees of elbow flexion. The contact area gradually decreased with an increase in the angle, and the minimum values were 210±3.82 and 236±6.59 mm at 120 degrees of elbow flexion. 3. When the elbow joint was extended, the maximum stress of the medial collateral ligament was 6.5±0.23, 11.5±0.78 and 18.7±0.94 MPa under different states; as the stress decreased with an increase in the angle, the corresponding values were 2.8±0.18, 4.8±0.56 and 6.2±0.72 MPa at 120 degrees of elbow flexion. Conclusion:The annular ligament plays an important role in maintaining elbow joint stability. When the annular ligament ruptures, it should be reconstructed as much as possible to avoid the elevation of stress on the surface of the medial collateral ligament of the elbow and on the annular cartilage, which may cause clinical symptoms.

Outcomes of radial head fractures treated with pre-curved metacarpal plate

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Investigating Elbow Dislocation and Instability: A 3D Finite Element Analysis Approach

“…The model was divided into three distinct areas based on the different material properties: cortical bone, cartilage, and ligaments. These material properties were assumed to be linearly elastic and isotropic, with numerical values sourced from literature [26,[35][36][37]The total number of elements utilized in the model was 66,672 tetrahedral elements. Contact elements specific to the elbow joint, along with boundary conditions derived from previous experimental data on posterior elbow dislocations [1], were incorporated to validate the model's accuracy.…”

“…In [26], MRI results were used to construct a finite element model for the cartilage and ligaments, which allowed to simulate different conditions for the annular ligament. Different buckling angles and muscle strengths were simulated.…”

“…This simplifies the representation of material properties within the model, allowing for streamlined analysis and computation. Material properties for the ulna, radius, humerus, cartilage and ligaments were obtained from literature [26,[35][36][37] (see Table 1) to ensure that the model accurately reflects the mechanical behavior of the anatomical structures within the elbow joint. In the final step before exporting the 3D model into ANSYS, the element types were defined as all tetrahedral.…”

Study of Damage to the Drawing Arm Subacromial Bursa in Recurve Archers Based on a Finite Element Model

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