Optimizing glenoid bone preservation in reverse total shoulder arthroplasty using augmented baseplates.

ABSTRACT

Background: As techniques and implants for reverse total shoulder arthroplasty (rTSA) evolve, a greater emphasis is being placed on preserving glenoid bone stock and optimizing shoulder biomechanics. Augmented baseplates preserve glenoid bone and improve shoulder range of motion by lateralizing the center of rotation of the glenosphere, while also reducing postoperative complications after rTSA. The technique for bone preservation with use of augmented baseplates in the absence of bone loss and the outcomes of a series of cases are contained in this report. Materials and Methods: A retrospective chart review was conducted for 37 patients with Walch type A1/Sirveaux E0 glenoids who underwent primary rTSA using a bone preserving technique with an augmented baseplate between January 2018 and January 2019 at a single site by a single surgeon. The primary outcome measures were range of motion, strength, and patient-reported clinical outcomes (pain and function rated on a visual analog scale; single assessment numeric evaluation; American Shoulder and Elbow Surgeons score; and disabilities of the arm, shoulder, and hand score). Preoperative radiographs were analyzed for the presence of glenoid bone loss and postoperative radiographs were assessed for evidence of component loosening and scapular notching. A repeated measures design was used, and preoperative and postoperative comparisons were made using parametric t-tests. Results: At an average follow-up of 23.3 ± 6.3 months, there was a significant improvement in active forward flexion and abduction and nonsignificant improvement in external rotation. There was no radiographic evidence of glenoid notching in any of the patients and optimal glenoid inclination was observed. Patient-reported outcome scores after an average of 25.2 ± 10.0 months indicated a significant improvement in pain, function, and scores for the American Shoulder and Elbow Surgeons and disabilities of the arm, shoulder, and hand assessments. There were no substantial postoperative radiographic findings, intra/postoperative complications, or revisions/reoperations. Conclusion: rTSA with augmented baseplates for glenoid bone preservation in patients with minimal or no bone loss is effective for preserving glenoid bone stock and significantly improves the range of motion and patient-reported outcomes after approximately 2 years.