Conversion of Failed Anatomic Total Shoulder Arthroplasty to Reverse Shoulder Arthroplasty Yields Similar Pain and Functional Outcomes to Primary Reverse Shoulder Arthroplasty But has a Higher Baseplate Failure Rate: A Matched Cohort Study.

BACKGROUND

To investigate whether patients who initially underwent anatomic total shoulder arthroplasty (aTSA) for glenohumeral osteoarthritis and were subsequently revised to reverse TSA (rTSA) due to rotator cuff failure or glenoid loosening ultimately attained a similar clinical outcome compared with those who underwent primary rTSA and identify predictors of poor outcomes in the former population.

METHODS

We did a single-center retrospective review of 63 shoulders who underwent revision rTSA after primary aTSA that failed due to glenoid component loosening (n = 32), rotator cuff failure (n = 24), or recurrent instability (n = 7). Pain and functional outcomes at minimum 2-year follow-up were compared between patients undergoing revision rTSA (n = 45) and a matched control group of primary rTSAs performed for primary osteoarthritis with an intact rotator cuff. Predictors of a poor American Shoulder and Elbow Surgeons score and baseplate loosening in the former cohort were identified.

RESULTS

After revision rTSA, patients demonstrated statistically significant (P < 0.05) improvement in overhead motion, functional outcome scores, and pain but no improvement in external or internal rotation. A 35% complication rate was observed, most commonly baseplate loosening (21%). The implant survivorship following revision rTSA was 97% after 2 years and 75% after 5 years. No notable differences in any outcome scores, range of motion, shoulder strength, or pain measures were found between revision rTSAs and matched primary rTSA controls at a mean of 8 years since index surgery. Humeral stem retention was independently associated with poorer postoperative American Shoulder and Elbow Surgeons scores, whereas a lesser interval between index and revision surgery and use of a structural bone graft were associated with a higher risk of baseplate loosening.

CONCLUSION

Patients who undergo aseptic revision rTSA after failed primary aTSA for cuff-intact glenohumeral osteoarthritis attain similar pain and functional outcomes compared with those who underwent primary rTSA when matched by time since index surgery.

LEVEL OF EVIDENCE

Level III, Case-Control Study.