Glenoid Bone-Grafting in Revision to a Reverse Total Shoulder Arthroplasty: Surgical Technique.

Introduction Reverse shoulder arthroplasty has emerged as a very good treatment option for patients in salvage situations, such as the revision setting with glenoid bone loss. Indications & Contraindications Step 1 Preoperative Evaluation and Planning For patients undergoing revision shoulder arthroplasty, perform the preoperative evaluation with radiographs, computed tomography (CT), and digital templating software as they play a key role (Video 1). Step 2 Surgical Approach and Humeral Component Management Perform all operations with the patient in the beach-chair position. Step 3 Glenoid Component Removal and Preparation Glenoid exposure is the key to the operation. Step 4 Assessment of Glenoid Bone Stock and Bone-Grafting Algorithm Use bone graft if the glenoid is thought to be inadequate for stable fixation in an acceptable position. Step 5-A Manage a Peripheral Defect with ≥50% Implant-Bone Contact with a Structural Allograft or Humeral Autograft When a peripheral defect contributes to either glenoid anteversion (anterior) or retroversion (posterior), but the implant has ≥50% contact with the native bone, consider using a structural autograft from the local humerus (preferred), if available, or a structural allograft (Video 1). Step 5-B Manage a Peripheral Defect with <50% Implant-Bone Contact with a Structural Autograft from the Iliac Crest or Proximal Part of the Humerus In shoulders with a peripheral defect with <50% contact with the native glenoid and substantial alterations in glenoid version, consider using a structural autograft from the proximal part of the humerus (preferred), if available, or the iliac crest (Figs. 2-A, 2-B, 2-C, and 3; Video 1). Step 5-C Manage a Central Defect with ≥30% Implant-Bone Contact with Morselized Bone-Grafting Allograft or Autograft In shoulders with a central defect with ≥30% contact between the baseplate and the native glenoid, with adequate primary stability of the central screw and/or peg, use morselized local autograft (preferred), if available, or corticocancellous allograft, to restore the lateral offset of the native glenoid and implant-bone contact area. Step 5-D Manage a Central Global Defect with <30% Implant-Bone Contact with a Structural Autograft from the Iliac Crest or Proximal Part of the Humerus As a large central or global deficiency can lead to excessive glenoid medialization (Figs. 4-A, 4-B, and 4-C), use a structural tricortical autograft from the iliac crest to restore glenoid structure and support implantation, as well as increase the offset of the glenoid component, enhancing stability and potentially reducing the risk of scapular notching8. Step 5-E Manage a Superior Defect with <50% Implant-Bone Contact and Loss of Tilt with a Structural Autograft from the Iliac Crest or Proximal Part of the Humerus For a superior deficiency with <50% contact between the implant and the native bone and a loss of neutral tilt, avoid superior tilt as it is critical to obtain either neutral or inferior tilt of the glenoid (keep this in mind when placing the central cannulated Kirschner wire for drilling the central screw) and use structural autograft for larger defects to prevent superior tilt, with the source of the graft preferentially from the humeral neck resection; however, if there is not adequate proximal humeral bone, a tricortical graft from the ipsilateral iliac crest can be used. Step 6 Placement of Baseplate Screws and Glenosphere and Implantation of the Humeral Component Step 7 Postoperative Care Results In our practice, glenoid bone-grafting was performed in 29% of the 143 shoulders revised using reverse components2. Pitfalls & Challenges