Abstract
BACKGROUND: Reverse shoulder arthroplasty (rTSA) provides reliable outcomes, but postoperative range of motion (ROM) varies. This study examined factors influencing the ROM after rTSA. METHODS: Seventy-three shoulders (70 patients) undergoing primary rTSA between 2014 and 2023 with ≥1-year follow-up were reviewed. Demographic, clinical, perioperative, and radiographic data were analyzed. Forward flexion (FF), external rotation (ER), and internal rotation (IR) were evaluated using multivariable linear regression to identify predictors. RESULTS: FF improved from 70° to 119° (p < 0.001), and ER from 12° to 22° (p = 0.002), whereas IR decreased from L3 to L4 (p = 0.009). Older age (β = -1.26, p = 0.003) and greater postoperative global lateralization, measured as lateral offset (β = -1.88, p = 0.001), predicted poorer FF, while taller height (β = 0.88, p = 0.015) and higher preoperative abduction (β = 0.26, p = 0.002) were favorable. For ER, older age was detrimental, whereas prior arthroscopic repair (β = 11.06, p = 0.031) and greater preoperative ER (β = 0.19, p = 0.041) were beneficial. No predictors were identified for IR. DISCUSSION: Older age and increased global lateralization limit elevation, whereas taller stature, preoperative abduction, and prior arthroscopic repair predict better motion.