Isolated Glenohumeral Corticosteroid Injection Versus Concomitant Capsule Preserving Hydrodilatation

This clinical trial investigates whether concomitant capsule-preserving hydrodilatation (CSHD) is more effective than isolated glenohumeral corticosteroid injection (CS) in treating shoulder adhesive capsulitis. The main questions it aims to answer are * Is CSHD inferior to CS in immediate pain relief as the solution is diluted? * Is CSHD superior to CS in improving the range of motion as the contracted capsule is dilated? Group CS will receive an ultrasound-guided glenohumeral corticosteroid injection only, with a solution of 5 mL. Group CSHD will receive an ultrasound-guided glenohumeral corticosteroid with hydrodilatation, with a solution of 20 mL. Clinical scores and range of motion will be compared between the groups up to six months post-injection.