Hypothesis: Reverse shoulder prostheses depend on deltoid function. An injury to the acromion, either fracture or meso-acromion, or deltoid injury, may affect the outcomes of patients after receiving a reverse shoulder prosthesis.
Methods: Four-hundred and fifty-seven consecutive reverse shoulder prostheses were implanted between January 1992 and June 2003 by one of seven surgeons in five separate centers. Forty-one patients were noted to have a pre-operative lesion of the acromion or scapular spine. Twenty-three presented with an os acromiale (meso-acromion). Seventeen had fracture or fragmentation of the acromion. One patient had a pseudarthrosis of the scapular spine.
Results: Preoperative acromial pathology, surgical approach, and amount of inferior acromial tilt did not diminished postoperative range of motion, Constant score, or subjective results when compared to patients without acromial pathology. In contrast, the four patients with postoperative acromial spine fractures had inferior results with respect to functional and subjective results.
Conclusion: Preoperative acromial lesions are not a contraindication to reverse shoulder arthroplasty. Postoperative fracture of the acromial spine has a significant effect on results and treatment is uncertain.