Background <p>The beach chair position, often used in shoulder surgery, increases the risk of hypotension and cerebral hypoperfusion. This randomized controlled trial evaluated the efficacy of leg elevation in preventing hypotension during total shoulder arthroplasty in the beach chair position.</p> Methods <p>Fifty patients scheduled for total shoulder arthroplasty in the beach chair position were randomly assigned to the control (25 patients) or treatment (25 patients) groups. The treatment group elevated their legs during surgery, whereas the control group maintained a neutral leg position. The primary outcome was the incidence of hypotension. The secondary outcomes included the incidence of cerebral desaturation, hemodynamic variables, and vasoconstrictor use.</p> Results <p>The incidence of hypotension did not significantly differ between the control and treatment groups (100% [95% CI: 86.3-100%] vs. 87.5% [95% CI: 67.6-97.3%]; <i>p</i> = 0.11). The incidence of cerebral desaturation was also similar between the control and treatment groups (84.0% [95% CI: 63.9-95.5%] vs. 91.7% [95% CI: 73.0-99.0%]; <i>p</i> = 0.67). However, the median [Q1-Q3] dose of phenylephrine was significantly higher in the control group than in the treatment group (3.5 [1.5–5.4] μg/kg vs. 1.6 [0.9–3.0] μg/kg; <i>p</i> = 0.02).</p> Conclusions <p>Intraoperative hypotension occurred in 93.9% of patients undergoing total shoulder arthroplasty in the beach chair position, regardless of leg elevation. However, leg elevation significantly reduced the need for vasoconstrictors to maintain blood pressure during anesthesia.</p> Trial registration <p>ClinicalTrials.gov (identifier: <a href="https://clinicaltrials.gov/study/NCT03393559?term=NCT03393559&amp;rank=1">NCT03393559</a>, date of registration: 2017–12-26).</p>