Editor’s note: The following content was published in the AAOS Now Special Edition and distributed in June 2020. The content was originally scheduled for the AAOS Now Daily Edition, which publishes each year onsite at the AAOS Annual Meeting but this year’s meeting in March was canceled due to COVID-19. Despite the cancellation, members can access virtual content from the Annual Meeting by visiting the Academy’s Annual Meeting Virtual Experience webpage.

A study found that patients undergoing reverse total shoulder arthroplasty (RTSA) experience the most significant pain reduction and functional gains within the first six months after surgery, followed by a plateau by 12 months after surgery. J. Michael Wiater, MD, chief of shoulder surgery in the Department of Orthopedic Surgery at Beaumont Health in Royal Oak, Mich., presented the study’s findings as part of the Annual Meeting Virtual Experience.

“Many patients are interested in how long it will take for them to recover or when they will experience maximum improvements,” Dr. Wiater told AAOS Now. “This study was undertaken to help answer these questions and allow us to better educate our patients so they can make a more informed decision with regard to undergoing RTSA.”

Researchers retrospectively analyzed a prospective database to identify patients with functional outcome data preoperatively and after primary or revision RTSA. Assessments included American Shoulder and Elbow Surgeons (ASES) score, visual analog scale (VAS) pain score, subjective shoulder value (SSV), and range of motion (ROM). Active internal rotation ROM was assessed as the highest spinal level that the patient’s thumb was able to reach and coded as: one point for end of thumb to lateral thigh, two points to the buttock, three points to lumbosacral junction, four points to L3, five points to T12, and six points to T7.

The study included 163 patients (mean age, 68 years; 68 percent were female) and 173 shoulders. Average preoperative ASES score was 33 and improved “dramatically,” according to Dr. Wiater, to 73 by three to six months (P < 0.001), 80 at one year (P < 0.001), and 81 at two years (P = 1.0) postoperatively. SSV scores and forward elevation followed the same pattern, with large improvements in the first three to six months, reaching a plateau at one year, and showing no significant difference between one and two years (P = 1.0). Forward elevation averaged 79 before surgery and improved to 116 at three to six months (P < 0.001), increased again to 125 at one year (P < 0.001), and remained at 126 by two years (P = 1.0). VAS pain scores improved from 6.8 points before surgery to about 1.3 points at all subsequent time points.

The exceptions to the findings were internal and external rotation outcomes: They did not significantly improve at the three- to six-month marks but did significantly increase at one year (P < 0.001), with no additional gains at two years. See Fig. 1 for all outcomes.

“We were surprised by how long the internal and external rotation measures took to improve,” Dr. Wiater told AAOS Now. “Patients should be counseled that internal and external rotation improve slower than forward elevation and may take up to a year before significant differences are noticed. Future research could investigate why there is such a delay in rotational improvements and ways to consistently maximize rotational gains.”

The study is limited by its retrospective design and heterogeneity of patient indications for undergoing RTSA.

Dr. Wiater’s coauthors of Paper 050, “Rate of Improvement in Outcomes Measures after Reverse Total Shoulder Arthroplasty: A Longitudinal Study with Two-Year Follow Up,” are Edward J. Shields, MD; and Denise Koueiter, MS.

Kerri Fitzgerald is the managing editor of AAOS Now. She can be reached at kefitzgerald@aaos.org.