Ulnar collateral ligament dysfunction increases stress on the humeral capitellum: a finite element analysis

Abstract

Background Repetitive mechanical stress on the elbow joint during throwing is a cause of ulnar collateral ligament dysfunction that may increase the compressive force on the humeral capitellum. This study aimed to examine the effects of ulnar collateral ligament material properties on the humeral capitellum under valgus stress using the finite element method. Methods Computed tomography data of the dominant elbow of five healthy adults were used to create finite element models. The elbows were kept at 90° of flexion with the forearm in the neutral position, and the ulnar collateral ligament was reproduced using truss elements. The proximal humeral shaft was restrained, and valgus torque of 40 N·m was applied to the forearm. The ulnar collateral ligament condition was changed to simulate ulnar collateral ligament dysfunction. Ulnar collateral ligament stiffness values were changed to 72.3 N/mm, 63.3 N/mm, 54.2 N/mm, 45.2 N/mm, and 36.1 N/mm to simulate ulnar collateral ligament laxity. The ulnar collateral ligament toe region width was changed in increments of 0.5 mm from 0.0 to 2.5 mm to simulate ulnar collateral ligament loosening. We assessed the maximum equivalent stress and stress distribution on the humeral capitellum under these conditions. Results As ulnar collateral ligament stiffness decreased, the maximum equivalent stress on the humeral capitellum gradually increased under elbow valgus stress ( P < .001). Regarding the change in the ulnar collateral ligament toe region width, as the toe region elongated, the maximum equivalent stress of the humeral capitellum increased significantly under elbow valgus stress ( P < .001). On the capitellum, the equivalent stress on the most lateral part was significantly higher than that on other parts ( P < .01 for all). Conclusion Under elbow valgus stress with elbow flexion of 90° and the forearm in the neutral position, ulnar collateral ligament dysfunction increased equivalent stress on the humeral capitellum during the finite element analysis. The highest equivalent stress was noted on the lateral part of the capitellum.

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.…”

“…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.…”

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,[38][39][40] . The total number of elements utilized in the model was 66,672 tetrahedral elements.…”

“…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,[38][39][40] (see Table 1) to ensure that the model accurately reflects the mechanical behavior of the anatomical structures within the elbow joint.…”

Update in diagnosis, treatment, and prevention of osteochondritis dissecans of the capitellum

“…Assessment of medial elbow laxity in patients with OCD is important because it may indicate the presence of valgus extension overload syndrome (VEOS), which is a condition that can cause OCD in children and adolescents. 69,70 By identifying medial elbow laxity, clinicians can anticipate the possibility of other future problems associated with VEOS, such as posterior impingement and ulnar collateral ligament complaints. This factor is examined by performing a valgus stress test with the elbow in 70° flexion.…”