Analysis of patients with differing short-term rates of improvement and long-term rates of decline in range of motion and after anatomic and reverse total shoulder arthroplasty.

Background: Patients with anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA) can have different short-term rate of improvement (ROI) and different long-term rate of decline (ROD) in range of motion (ROM). This study aims to quantify and compare these rates and identify risk factors associated with a slow ROI and a fast ROD after both aTSA and rTSA. Methods: This 8-year minimum longitudinal outcome study compares active ROM in 1272 primary aTSA (n = 688) and rTSA (n = 584) patients across 8357 visits and identified patient cohorts with a slow, average, and fast ROI from 0-2 years after surgery and a slow, average, and fast ROD 8 years after surgery relative to peak improvement achieved 2-3 years after surgery. A multivariate regression analysis was performed to identify patient, implant/operative, or postoperative risk factors associated with a slow ROI and fast ROD after both aTSA and rTSA. Results: The results of this 1272 patient long-term clinical outcome study demonstrates that aTSA and rTSA patients with a slow ROI were associated with high preoperative ROM and patients with a fast ROI were associated with low preoperative ROM. aTSA and rTSA patients with high preoperative ROM experienced declines in ROM during the first 3 months, but later recovered at a similar rate and achieved similar peak improvements. aTSA patients with a slow ROI had significantly higher preoperative abduction, internal rotation score, and external rotation, whereas rTSA patients with a slow ROI were significantly more likely to have diabetes, injections, and significantly higher preoperative abduction and internal rotation score. aTSA patients with a fast ROD were significantly more likely to have heart disease and glenoid radiolucent lines, whereas rTSA patients with a fast ROD were significantly more likely to have comorbidities and experience revision surgery. Discussion: The rate of improvement in ROM during the short-term recovery period after aTSA and rTSA is highly dependent on preoperative ROM, whereas the rate of decline in ROM at long-term follow-up is generally impacted by systemic health issues (ie, heart disease and more comorbidities), compromised implant fixation (ie, radiolucent lines after aTSA), and the onset of revision surgery. These findings may be beneficial for patient counseling and expectation management, especially to encourage patients who may have experienced a decline in ROM during the first 3 months after surgery.