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

Cortisone calms inflammation in the crowded space around the shoulder tendons. It does not change every cause of impingement, such as movement coordination, tendon irritation, or weakness. If a numbing medicine was included, you might notice short-lived relief soon after the injection; this is separate from the later cortisone response. Reduced pain can make movement easier, but it does not mean the shoulder is ready for heavy overhead work.

Use the less painful period to practise the movements and strengthening recommended by your physiotherapist. Keep activity below the level that provokes sharp pain, and increase reaching, lifting, and sport gradually. Protect the shoulder from sudden overhead loading while it is sore. Record whether sleep, dressing, and reaching improve, since these changes help your clinician judge the response.

Get advice if pain is steadily worsening, the shoulder becomes hot and increasingly swollen, or you develop fever or feel unwell. Seek urgent help for facial swelling or breathing difficulty. If the expected benefit does not appear within the review period agreed with your clinician, book an assessment rather than repeating strenuous activity to test it.

Ask which exercises are appropriate now, how long to avoid overhead lifting, how to distinguish injection soreness from a flare, and when your shoulder should be reassessed.