This is the first completely independent study to confirm that the ISIS is a useful preoperative tool. It is recommended that surgeons consider alternative forms of stabilization if the ISIS is ≥4.

Background Symptoms of shoulder impingement are very common in clinical practice; however, diagnosis of the exact cause of the impingement remains a challenge. Evidence‐based guidelines published for physiotherapists state that night pain is particularly associated with rotator cuff tears. This retrospective study aimed to determine whether patients diagnosed with impingement of the shoulder are more likely to report night pain if a tear of the rotator cuff is present. Methods The findings at surgery of 873 patients following open or arthroscopic decompression of the shoulder were studied to determine whether a tear of the rotator cuff had been identified. The pre‐operative response for each of these patients regarding sleep disturbance as a result of their shoulder pain was cross‐matched with the surgical findings. Results There was no significant difference between those patients who were found to have a cuff tear and those with an intact rotator cuff and their complaint of night pain. Discussion Night pain is a common complaint of patients presenting with impingement of the shoulder. It cannot be used in isolation as a diagnostic predictor for the presence of a rotator cuff tear.