How long does a cortisone injection take to work for shoulder osteoarthritis?

Cortisone reduces inflammation inside or around the painful joint. It does not rebuild worn cartilage or reverse the underlying arthritis. A local anaesthetic may provide an earlier, brief change in pain, which is not the same as the cortisone effect. If joint stiffness, reduced strength, or pain from certain positions remains, the injection may be only one part of symptom management.

Keep the shoulder relatively quiet for the period advised by your clinician, then resume comfortable movement. Gentle mobility can reduce stiffness, while a tailored strengthening programme supports daily tasks. Pace dressing, reaching, and carrying, and avoid using a temporary reduction in pain to lift more than usual. Note changes in sleep and everyday movement for your follow-up.

Call the clinic if post-injection pain keeps increasing, the area becomes hot or markedly swollen, or fever develops. Seek urgent help for breathing difficulty, facial swelling, or other signs of a severe allergic reaction. Arrange a review when the agreed follow-up arrives, especially if pain, stiffness, or loss of function has not improved.

Ask whether the injection was placed in the joint or nearby tissues, when to restart exercises, what alternatives are available if relief is short-lived, and how to manage flare-ups safely.