Irreducible isolated anteromedial radial head dislocation due to ruptured anterior capsule and annular ligament interposition: A case report

Abstract

Traumatic radial head dislocation without a bone-associated lesion is uncommon, and irreducible cases are rare. We herein present a case of isolated irreducible anteromedial radial head dislocation due to anterior capsule and annular ligament interposition in a 16-year-old female patient. The patient was injured when she was thrown by an opponent during a judo match, and her right elbow was outstretched, combined with forearm pronation. Open reduction was required because of soft tissue interposition into the radiocapitellar joint. The ruptured anterior capsule and annular ligament were repaired using the overlapping suture technique; hence, the radial head was stabilized. At 3.5 years follow-up, the patient had satisfactory elbow function, and redislocation did not occur; however, mild degenerative changes were observed on radiographs. We discussed the injury mechanism using anatomical features in this case and previous literature.

Keywords: annular ligament; anterior capsule; elbow; irreducible radial head; radial head dislocation.

Figure 1.

Radiographs of the anteroposterior view of the elbow (A, B) and lateral view of the forearm (C, D). Injured side (A, C) and contralateral side (B, D). The radial head was dislocated anteromedially. No fracture and plastic bowing of the ulna were observed. The maximum ulna bow was 4 mm on the injured side and 3 mm on the contralateral side.

Figure 2.

MRI of short T1 inversion recovery was obtained 2 weeks post-injury. Sagittal view of the ulnar side (A), radial side (B, C), and coronal view (D). Soft tissue interposition from the anterior aspect into the RCJ was observed (white allow head). Signal change indicative of rupture was observed in MCL (*).

Figure 3.

Intraoperative view (A) and schema (B). The ruptured anterior capsule and annular ligament were interposed into the radiocapitellar joint (RCJ), and the radial head (*) was observed from the extra-articular space.

Figure 4.

Radiographs at the final follow-up of 3.5 years postoperatively. Anteroposterior view (A) and lateral view (B). Heterotopic ossification at the medial side of the elbow joint and degenerative changes around the radiocapitellar joint (RCJ) were observed.

Figure 5.

Active range of motion (ROM) at the final follow-up of 3.5 years postoperatively. Extension (A) and flexion (B).

Figure 6.

Proximal ulnar dorsal angulation (PUDA) was −4.4° on the injured side (A) and −3.8° on the contralateral side (B). The proximal ulna is inclined dorsally on both sides.