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.

Acromial base fractures after reverse total shoulder arthroplasty: report of five cases.

BACKGROUND: Most series of reverse total shoulder arthroplasty (rTSA) have reported acromial fractures, but they have not been shown to alter reported outcomes in most series. We present 5 patients with acromial base fractures where the entire deltoid origin was displaced from its anatomic location. MATERIALS AND METHODS: Five patients with acromial base fractures after rTSA were identified and evaluated for functional outcomes and pain relief as well as results of fracture treatment. Three were treated operatively and 3 were treated nonoperatively. One nonoperative treatment eventually required open reduction and internal fixation. RESULTS: Function was limited after fracture, with average forward elevation of only 43° but which improved to 84° after fracture union. Pain was significant after the fracture (6.8 of 10) and improved with fracture healing (0.8 of 10). Neer Functional Outcome scores after fracture union averaged 62 of 100, consistent with unsatisfactory results. CONCLUSION: Acromial base fractures after rTSA are a painful and disabling complication. The outcomes appear different in this series than in other series describing acromial fractures. This may be a result of the different anatomic location of the fractures. Pain improves with fracture union, but functional returns are unpredictable.