Irreducible Isolated Radial Head Dislocation in a Child Due to Annular Ligament Interposition: A Case Report

Abstract

The annular ligament of the elbow is essential for its stability, playing a key role in both the proximal radioulnar and humeroradial joints, as well as supporting surrounding muscles and ligaments. Radial head dislocation is rare in children, and when isolated they can be challenging to reduce and may require surgical intervention. An 11-year-old boy presented with an anteromedial dislocation of the radial head after a fall. Initial, closed reduction was attempted and failed, requiring surgical intervention, where we found a rupture of the annular ligament and interposition, which was repaired after reduction. At one year of follow-up, the patient achieved full range of motion and stability of the elbow. Radial head dislocation is rare in children and even more rare without associated ulna fractures. Evaluating radiographs for plastic deformities of the ulna is crucial, as these injuries are often overlooked. Failed closed reductions may rise suspicion of interposed structures. Isolated post-traumatic radial head dislocation is a rare occurrence requiring prompt recognition and management. While most cases are treated with closed reduction, those that are not reducible or suspected soft tissue interposition may require open reduction. Thorough clinical evaluation, both vascular and neurologic and preoperative imaging are essential. Early intervention and meticulous surgical techniques can lead to favorable functional outcomes.

Keywords: annular ligament; irreducible radial head; pediatric elbow trauma; radial head dislocation; radial head open reduction.

Figure 1. X-ray and computed tomography scan of radial head dislocation of the right elbow.

1A shows an anteroposterior radiographic view of radial head dislocation of the right elbow; 1B shows a lateral radiographic view of radial head dislocation of the right elbow; 1C and 1D show a 3D reconstruction of a computed tomography scan of radial head dislocation of the right elbow.

Figure 2. Identification and reattachment of the annular ligament.

The images (A and B) illustrates the identification and reattachment of the annular ligament.

Figure 3. X-ray showing the intra-operative reduction of radial head dislocation of the right elbow.

3A shows the lateral radiographic view of the right elbow; 3B shows the anteroposterior radiographic view of the right elbow.

Figure 4. X-ray of right (A, B) and left (C, D) elbow at one year of follow-up.

4A shows a lateral radiographic view of the right elbow; 4B shows an anteroposterior radiographic view of the right elbow; 4C shows a lateral radiographic view of the left elbow; 4D shows an anteroposterior radiographic view of the left elbow.

Figure 5. Symmetric flexion-extension and pronation-supination compared to the contralateral elbow.

5A shows symmetric supination and extension of the elbows; 5B shows symmetric flexion of the elbows; 5C shows symmetric pronation and extension of the elbows.