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

The purpose of this study was to define an age cutoff at which clinical outcomes and revision rates differ for patients undergoing primary anatomic total shoulder arthroplasty (TSA) and patients undergoing primary reverse shoulder arthroplasty (RSA). 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. 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 represents T4 to T6 and 4 represents T11 to L1—than their younger counterparts. 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.