2025 Volume 4 Issue 2 Pages 85-92
Objective: We used ultrasound imaging to observe the dynamics of the radial head and interpret the pathophysiology in two cases of lateral epicondylitis of the humerus.
Case: Both patients were men in their fifties, with a chief complaint of lateral elbow pain when holding an object. In both cases, joint range of motion was decreased in wrist grip flexion and rotation at 0° elbow extension, and tenderness was observed in the lateral epicondyle of the humerus, extensor carpi radialis brevis, and extensor digitorum. The lateral and anterior displacement dynamics of the radial head were measured using ultrasound imaging, and the amount of change and displacement angle were calculated. In both cases, the lateral displacement of the radial head decreased, the anterior displacement increased excessively, and the displacement angle was larger on the affected side than on the healthy side. After the extensibility of the extensor carpi radialis brevis and extensor digitorum muscles and gliding around the radial ring ligament were improved, the range of motion increased, the forward displacement and angle of displacement decreased, and pain disappeared.
Conclusion: These results suggest that the limitation of the range of motion and changes in displacement caused by increased tension in the annular ligament of the radius and extensor digitorum muscles may be related to this pathophysiology.
