An Irreducible Posterior Fracture-Dislocation of the Shoulder: A Case Report

Posterior fracture-dislocations of the shoulder are exceedingly rare orthopedic injuries. The management of these rare and complex injuries can be challenging from initial presentation through definitive management. Timely diagnosis of these injuries is critical to prevent devastating complications, yet the diagnosis is often delayed. Delays in surgery and poor fracture reduction are associated with a high risk of complications such as avascular necrosis. Additionally, these injuries have the potential to be irreducible. This may occur secondary to osteochondral humeral defects, soft tissue interposition, or entrapment. The long head of the biceps tendon incarceration is one potential block to reduction. Definitive surgical treatment options include open reduction and internal fixation (ORIF) and shoulder arthroplasty. While reoperation rates are higher in patients undergoing ORIF, arthroplasty longevity is a concern among young, active patients with high functional demands. Fibular strut allograft is a useful adjunct when reconstructing complex proximal humerus fractures. We present a case of a 28-year-old male who sustained a significantly comminuted four-part left proximal humerus fracture with an irreducible posterior humeral head dislocation requiring urgent ORIF following a motor vehicle accident.