Defining the younger patient: age as a predictive factor for outcomes in shoulder arthroplasty

Background: The purpose of this study was to define an age cutoff at which clinical outcomes and revi- sion rates differ for patients undergoing primary anatomic total shoulder arthroplasty (TSA) and patients undergoing primary reverse shoulder arthroplasty (RSA). Methods: This retrospective cohort study included 1250 primary shoulder arthroplasties (1131 patients) with minimum 2 -year clinical follow-up (mean, 50 months [range, 24-146 months]). TSA (n = 518; mean age, 68.1 years [range, 28-90 years]) was performed for osteoarthritis in most cases (99%), whereas the primary diagnoses for RSA (n = 732; mean age, 70.8 years [range, 22-91 years]) included rotator cuff arthropathy (35%), massive cuff tear without osteoarthritis (29.8%), and osteoarthritis (20.5%). Outcomes included range of motion, the American Shoulder and Elbow Surgeons (ASES) score, and the revision rate. The relationship between age at the time of surgery in 5 -year increments (46-50 years, 51-55 years, and so on) and the revision rate was examined to identify the age cutoff; this was then used to assess clinical outcomes. Results: In patients younger than 65 years, TSA was associated with a 3.4 -fold increased risk of revision ( P = .01). RSA performed in patients younger than 60 years was associated with a 4.8 -fold increased risk of revision ( P < .001). TSA patients aged 65 years or older and RSA patients aged 60 years or older had better total ASES scores (82 vs. 77 [ P = .03] and 72 vs. 62 [ P = .002], respectively) and better internal rotation (interquartile range, TSA 5-6 vs. 4-5 [ P = .002] and RSA 4-5 vs 3-4 [ P = .04]) -where 6 rep- resents T4 to T6 and 4 represents T11 to L1 -than their younger counterparts. Conclusion: Age at index arthroplasty affects outcomes and the risk of revision. Primary TSA patients younger than 65 years and RSA patients younger than 60 years have a significantly increased revision risk. These age cutoffs are also correlated with differences in ASES scores and internal rotation. Level of evidence: Level III; Retrospective Cohort Comparison; Treatment Study ? 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. All rights reserved.