Fifty-six patients with subacromial impingement syndrome (SIS) were randomized to receive either exercise therapy (ET) alone (n=28) or exercise therapy with two doses of Platelet-Rich Plasma (PRP) injections (n=28). The primary outcome was pain reduction, assessed by the Visual Analog Scale (VAS). Secondary outcomes included functionality (Constant-Murley Score, CMS) and QoL (SF-36). Outcomes were...