Difficulty in Early Diagnosis of Bilateral Posterior Fracture-dislocation of the Shoulder Caused by an Electric Shock in a Walk-in Patient: A Case Report

Abstract

Introduction: Bilateral posterior fracture-dislocation of the shoulder is a very rare injury that is commonly missed. Almost 70% of bilateral posterior dislocations are due to convulsive seizures, with electric shocks accounting for < 5% of bilateral posterior shoulder dislocations.

Case report: The case of a walk-in patient, a 52-year-old man, with bilateral posterior fracture-dislocation of the shoulder caused by an electric shock is reported. Although he was initially admitted to the emergency department for observation of the potential complications of an electric shock, such as fatal arrhythmia and rhabdomyolysis, he subsequently consulted an orthopedic surgeon 4 days after the event due to persistent bilateral shoulder pain and was diagnosed using X-ray and computed tomography with bilateral posterior fracture-dislocation of the shoulder. Following open reduction and internal fixation 7 days after the injury, the upper limbs were fixed with shoulder braces at a slightly flexed and abducted position with neutral rotation for 3 weeks postoperatively followed by range of motion exercises. Twelve months after surgery, he had a Constant shoulder score of 94, an American Shoulder and Elbow Surgeon score of 100, and no shoulder re-dislocation or humeral head necrosis.

Conclusion: In this walk-in patient, the diagnosis of bilateral posterior fracture-dislocation of the shoulder caused by an electric shock was delayed. We believe that understanding the mechanism of this type of injury will facilitate its early diagnosis.

Keywords: Bilateral; electric shock; posterior fracture-dislocation; shoulder.

Figure 1

Anteroposterior plain radiographic views of the right (A) and left (B) shoulders show bilateral proximal humeral fractures. Although the right humeral head is internally rotated and dislocated (A) and dislocation of the left counterpart is not obvious (B).

Figure 2

Axial computed tomography (CT) of the right (A) and left (B) shoulders shows impaction fractures of the anteromedial area of the humeral head at the posterior glenoid rim. The right humeral head is posteriorly dislocated (A). The central axis of the left humeral head is shifted posteriorly toward the glenoid on axial CT images, indicating posterior subluxation of the left shoulder (B). 3D-CT of the right (C) and left (D) shoulders shows reverse Hill-Sachs lesions and fractures of the greater and lesser tuberosities. The red arrows indicate the reverse Hill-Sachs lesions. The white arrows indicate the greater and lesser tuberosities. The yellow arrows indicate the lesser tuberosities (C and D).

Figure 3

Intraoperative views of the left shoulder. The dashed line indicates the position of the bone defect (A). The 2.0-mm bioabsorbable pins (Osteotrans Plus™ ®Zimmer Biomet, Warsaw, IN, USA) are used to fix the bone fragments of the reduced reverse Hill-Sachs lesions to their counterparts on the humeral head. The yellow arrow indicates the artificial bone filling the bone defect (B). The white arrows indicate the articular surface (A and B). The arrowhead indicates the reduced bone fragments of the lesser tuberosity (C). After the reduction and fixation of the reverse Hill-Sachs lesion, the bone fragments of the lesser tuberosities are reduced and fixed with cannulated screws.

Figure 4

Post-operative axial computed tomography (CT) of the right (A and C) and left (B and D) shoulders and X-rays of the right (D) and left (F) shoulders at 12 months. CT shows reduced reverse Hill-Sachs lesions of the humeral heads without re-dislocation (A and B). It also shows bone union (C and D). Plain radiographs show neither band-like sclerosis in the humeral head or progression of collapse of the humeral head due to humeral head necrosis (E and F).