Traumatic Glenosphere Dissociation Following Reverse Total Shoulder Endoprosthetic Reconstruction for Proximal Humerus Periosteal Chondrosarcoma: A Case Report.

Introduction: Reverse total shoulder endoprosthetic reconstruction after margin-negative tumor resection of the proximal humerus is becoming more conventional in orthopeadic oncology practices. Mid-term survival and functional outcomes have been satisfactory. This case report corroborates with current literature and further describes a rare traumatic complication.

Case Presentation: We report a case of a 70-year-old male with periosteal chondrosarcoma of the proximal humerus who underwent margin-negative resection and reverse total shoulder endoprosthetic reconstruction that was complicated by glenosphere dissociation sustained from falling onto a hyperflexed arm. Successful revision arthroplasty was performed.

Conclusion: Enhancing glenohumeral joint stability after wide resection of the proximal humerus is important to address rotator cuff insufficiency. The greater levering effect of a longer humeral prosthesis used to increase soft tissue tension may also increase the risk of glenosphere dissociation secondary to trauma. Proper soft-tissue tensioning and surgical technique are critical.