Results of a stemless reverse shoulder prosthesis at more than 58 months mean without loosening

Abstract

Hypothesis: A stemless reverse shoulder prosthesis with humeral cup was developed to allow stemless press-fit fixation, to preserve bone stock. Our hypothesis was that a stemless reverse shoulder arthroplasty could produce the same functional results without compromising humeral fixation.

Methods: This is a continuous, prospective, single-surgeon series including prostheses implanted from 2004 to 2009. Patients received pre- and postoperative clinical evaluation with measurement of joint mobility, the Oxford Shoulder score, and the Constant-Murley score by independent evaluators. Standard radiographs and computed tomographic arthrography were performed.

Results: Fifty-six implants were reviewed at a mean of 58 months (38-95). The Constant-Murley score improved from 29 to 62 points and the Oxford Shoulder score from 46 to 17 points. Active elevation in forward flexion improved from 79° to 140°. One intraoperative complication was recorded: a metaphyseal-diaphyseal humeral bone crack without consequence. One revision surgery due to early instability was performed using a conventional implant. No humeral loosening was observed. Five cases of scapular notching were reported.

Conclusion: This is the first study reporting results with mid-term follow-up for a stemless reverse shoulder arthroplasty. The clinical results are comparable to conventional prostheses with stem. The absence of a humeral stem preserves bone stock for possible later revisions.

Keywords: Cases Series; Level IV; Shoulder arthroplasty; Treatment Study; reverse shoulder arthroplasty; stemless prosthesis.