The rotator cuff is a group of tendons involved in the positioning and moving of the shoulder joint. The rotator cuff lets people lift their arm and reach overhead. In a lot of people, wear and tear of the rotator cuff tendons is a normal part of ageing and they may not have symptoms. However, many people will develop pain in their shoulder at some point as the tendons degenerate further and tears in the rotator cuff tendons develop. There may also be inflammation of the shoulder tendons or bursa (a sac with internal gliding surfaces that helps the shoulder to move). Often the pain is made worse by sleeping on the affected shoulder and moving the shoulder in certain directions. Often there will be pressure on the tendons by the overlying bone when lifting the arm up. This is called impingement. It may become difficult to use the shoulder in every day activities, sports or work.
If the pain does not go away by itself or with treatments such as steroid injections or physiotherapy, surgery may be performed. Imaging tests such as magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA) and ultrasound (US) are used to assess the presence and size of rotator cuff tears to assist in the planning of the surgery.
Rotator cuff tears can be classified as full or partial thickness tears based on the extent or size of the tears. No test is 100% accurate in identifying tears or assessing their size. The accuracy of the tests is commonly assessed by the sensitivity of the test (the proportion of people who had a tear according to the test, among patients with tears), and specificity (the proportion of people without tears on the test, among patients with no tears).
We searched electronic databases up to February 2011, as well as trial registers, conference proceedings and reference lists of articles, for studies comparing diagnostic tests for people with suspected rotator cuff tears. Our review included 20 studies (1147 shoulders). Many studies had design flaws, which limited the reliability of their findings. We found that MRI, MRA and US may have similar accuracy for detecting the presence of full thickness tears. For identifying any tears (no distinction between partial or full thickness) or identifying partial thickness tears, MRI and US may also have similar accuracy. However, it appears that compared with US, MRI may be more sensitive in identifying partial thickness tears. With these results we can conclude that all three imaging tests (MRI, MRA and US) may help decisions regarding referral for surgery for people with suspected full thickness tears. Information on adverse effects of using these tests was not reported by the included studies.