Are Volume Criteria Warranted for Surgeons Performing Reverse TSA?
More than a decade after the first prosthesis for reverse total shoulder arthroplasty (RTSA) was approved in the US, a study from Johns Hopkins University has found a persistently high rate of device-related complications associated with the procedure, possibly due to a steep learning curve for surgeons.
For the study, which was presented at the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons, the researchers mined the database of cases submitted to the American Board of Orthopedic Surgeons by Part II candidates. Their goals were to evaluate growth in the number of procedures performed annually and to review data on outcomes and complications.
The Part II candidates had performed 2638 RTSAs between 2005 and 2017. The mean follow-up was 9.6 weeks (range, 0 to 30 weeks). More than half (64%) of patients in the database were women, and the mean age was 72 (range, 14 to 96 years).
The researchers found a device-related complication rate of 19.03%, with an overall complication rate of 25%. The latter remained consistent throughout the study period, which surprised the study authors.
“Numerous studies have shown a significant learning curve in regard to reverse shoulder replacement, and shoulder arthroplasty in general,” said lead study author Stephen C. Weber, MD.  “Perhaps the greatest surprise in the data was that the rate of complications was unchanged over the course of the study, despite all efforts in training and surgeon education.”
The number of RTSA cases increased 20-fold each year during the study period, although surgeons reported that these procedures accounted for only 2.61% of their practice (3.4 cases/candidate). This may be at least part of the reasons for the high complication rate: Some surgeons simply don’t perform enough RTSAs to become proficient with the procedure and experienced enough to manage the associated complications.
“The results certainly suggest that RTSA should not be approached casually by the surgeon recommending it,” Dr. Weber said.
Interestingly, fellowship training was not associated with a lower device-related complication rate, which the study authors said may reflect that fellowship-trained surgeons are taking on more challenging cases.
In the US, the initial approved indication for the reverse prosthesis was cuff tear arthropathy, limiting the procedure to patients with severe arthritis, massive rotator cuff tears, and a functioning deltoid. Over the years, surgeons have offered the procedure to a broader patient population but pushing the indications for RTSA doesn’t seem to be the issue: Off-label use of the prosthesis was not associated with a higher rate of complications, Dr. Weber said, except for medical complications in patients with fractures.
The study authors said that volume criteria may be warranted to reduce the rate of complications associated with RTSA, as has previously been suggested for hip arthroscopy. 
“It appears that at least for now, consideration should be given to RTSA being performed by surgeons whose surgical volume will provide reasonable outcomes,” Dr. Weber said. “This issue was expressed at the onset of the American RTSA experience,  and it appears to be true today as well.”
Weber SC, Srikumaran U, Joseph J, McFarland EG. Reverse Shoulder Replacement: Incidence Rates, Complications, and Outcomes in 2,638 Patients as Reported by ABOS Part II Candidates from 2005 through 2017 (Paper 376). Presented at the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 12-16, Las Vegas, Nevada.
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