Glenohumeral Arthrodesis for Treatment of Unique Instability with Axillary Nerve Injury: A Case Report.

Introduction: Traumatic shoulder dislocations in elderly patients can result in significant shoulder pathology. Rotator cuff tears and recurrent instability are common complications follow a dislocation event, while axillary nerve injury is less common. While there have been rare cases of recurrent shoulder instability with concomitant axillary nerve injury, there have been no prior cases, in which concurrent fracture fragmentation resulted in the initial gross instability. Case Report: A 68-year-old male with painful gross instability presents following a traumatic dislocation. The patient sustained an axillary nerve injury to the ipsilateral side resulting in a non-functioning deltoid. Pre-operative X-rays showed recurrent chronic glenohumeral dislocation, computerized tomography imaging showed a greater tuberosity fracture, and magnetic resonance imaging showed a massive cuff tear with retraction and atrophy. Given the level of instability and deltoid dysfunction, the patient was treated with shoulder arthrodesis. Intraoperatively, a large fragment of greater tuberosity with ligamentous attachments was found adhered to the anterior glenoid. After arthrodesis, the patient's pain and function improved significantly. Conclusion: When treating elderly patients with gross instability following a traumatic dislocation, surgeons should keep in mind the high likelihood of concomitant avulsion fracture, and that migratory cortical fragments can be a nidus for a patient's instability. When selected for appropriately, these patients can be effectively treated with shoulder arthrodesis with excellent improvements of pain and functionality.