Anatomic or reverse total shoulder arthroplasty? How fellowship training affects selection of arthroplasty type.

Background: Although both anatomic (ATSA) and reverse total shoulder arthroplasty (rTSA) have been popularized as a means of treating individuals with degenerative shoulder conditions, the indications for each can vary widely among providers. Although surgeons with differing fellowship training commonly perform these procedures, it is not understood how fellowship training influences choice of implant.

Methods: A national database was queried to identify surgeons performing ATSA and rTSA. For all surgeons who performed more than 10 cases between 2010 and 2022, fellowship data were individually collected via an online search. For each fellowship group, rates of ATSA and rTSA were identified using International Classification of Diseases procedural codes. Those who underwent revision arthroplasty and those with a history of fracture, infection, or malignancy were excluded. Primary outcome measures included the proportion of primary and revision ATSAs and rTSAs by fellowship in addition to the rate of rTSA performed for a primary diagnosis of glenohumeral osteoarthritis.

Results: A total of 131,974 patients met the inclusion criteria and were retained for this study. The proportion of rTSAs increased from 50.1% of all primary shoulder arthroplasty cases in 2011 to 72.0% in 2022. After adjusting for age and comorbidities, Sports Medicine fellowship-trained (Sports) surgeons opted for primary rTSA over ATSA at a significantly higher rate than Shoulder and Elbow fellowship-trained (Shoulder) surgeons and surgeons who completed another type of fellowship or no fellowship (Other). Sports surgeons also chose rTSA more frequently for the diagnosis of glenohumeral osteoarthritis than Shoulder surgeons. Surgeons in the Other cohort were more likely to perform primary ATSA rather than rTSA in comparison with surgeons in the Shoulder and Sports cohorts. Sports surgeons were responsible for the greatest increase in the percentage of all shoulder arthroplasty procedures from 2010 to 2022 (28.4%-40.4%), whereas the Other group decreased by a comparable amount (45.9%-32.4%) over the same period.

Conclusions: Surgeons who have completed a Sports Medicine fellowship choose rTSA over ATSA at a higher rate than Shoulder and Elbow surgeons, both for all indications and for a primary diagnosis of glenohumeral osteoarthritis. Those who have no fellowship training or fellowship training outside of Sports Medicine and Shoulder and Elbow surgery have the highest percentage of ATSAs in their arthroplasty practice. Revision ATSA and revision rTSA represent a larger percentage of overall case volume for Shoulder and Elbow surgeons.