The outcomes of shoulder arthroplasty in those aged ≥70 years with glenohumeral arthritis: a New Zealand Joint Registry study.

Introduction: Reverse total shoulder arthroplasty (RTSA) was traditionally reserved for the patient with rotator cuff tear arthropathy. As the indications for RTSA continue to expand, the role of RTSA in patients aged >70 years with glenohumeral arthritis and an intact rotator cuff remains unclear.

Aim: To study the New Zealand Joint Registry (NZJR) and compare the outcomes of a primary Total Shoulder Arthroplasty (TSA), a primary RSA and an RSA performed for revision of a failed TSA in patients aged >70 years, to determine if there is clear evidence to support a primary RSA in those aged >70 years instead of a primary TSA METHOD: This is a retrospective study of the NZJR from 2000 to 2018. We included all primary TSAs, primary RTSAs, and those RTSAs that were performed for the revision of a failed TSA. We excluded those RTSAs that were performed for the revision of an RTSA or hemiarthroplasty. The primary outcome was the Oxford Shoulder Score (OSS) at 6 months and 5 years, with a secondary outcome being the subsequent revision rate.

Results: A total of 3449 primary TSAs, 4681 primary RTSAs, and 104 revision RTSAs were identified. The mean OSSs at 6 months for a primary TSA, a primary RTSA, and a revision RTSA were 39.5 ± 9.0, 35.5 ± 9.4, and 32.5 ± 9.7, respectively (P < .001, primary TSA vs. primary RSTA; P <.001, primary TSA vs. revision RTSA; P = .0252 primary RTSA vs. revision RTSA). The mean OSSs at 5 years for a primary TSA and a primary RTSA were 42.1 ± 7.5 vs. 39.8 ± 8.4, respectively (P < .001), with no results available for revision RTSA. The secondary outcome was the revision rate for those aged >70 years with osteoarthritis as their primary indication for surgery. The revision rates for a primary TSA and a primary RTSA were 0.53/100 component-years (95% confidence interval [CI] 0.38-0.72) and 0.51/100 component-years (95% CI 0.31-0.79), respectively (P = .193), which was not statistically significant.

Conclusion: The TSA remains the gold standard for primary shoulder arthroplasty. For those individuals aged >70 years with osteoarthritis as their primary diagnosis, a primary TSA is associated with a higher OSS than and similar revision rates to a primary RTSA's. However, these patients must be counseled regarding the risk of subsequent cuff failure, as the outcomes from a revision RTSA are significantly inferior than those from a primary RTSA.