Approach
Diagnosis of rotator cuff tear is made based on a careful history and physical exam.
Radiographs should be obtained in the presence of trauma or if there is concern that a tumor or infection may be present. Advanced imaging is reserved for those who do not respond to conservative treatment, including physical therapy.
History
The patient's history should include a discussion of any inciting injury, symptom-limiting and pain-eliciting activities, vocational requirements, and treatment goals. Antero-lateral shoulder pain is the most common presenting symptom of rotator cuff tear, and pain is usually worse at night when lying on the affected shoulder. It is common for pain to radiate to the deltoid insertional area. Pain is typically aggravated by overhead activities.
Patients may also complain of functional weakness, loss of motion, and deltoid pain. Acute pain and weakness may be seen following traumatic rotator cuff rupture.
Physical exam
Examination should document strength of the rotator cuff, signs of impingement, and range of motion, especially elevation and internal and external rotation. Loss of active motion but retention of passive motion is highly suggestive of a full-thickness rotator cuff tear. A classic and most convincing sign of a full-thickness tear is weakness with resisted external rotation with the arm at the side and elbow flexed to 90°. This reflects involvement of the infraspinatus and suggests a larger tear.
A combination of four tests can be used to assess the strength of the rotator cuff.
Empty-can test: evaluates the supraspinatus. The patient raises both arms slightly forward from the coronal plane of the trunk with thumbs pointing to the floor (as if emptying a can). The examiner applies pressure to the top of the arms, which the patient attempts to resist. Weakness indicates a supraspinatus tear. [Figure caption and citation for the preceding image starts]: Empty-can testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
External rotation test: isolates the infraspinatus. With the arm at his or her side and the elbow flexed to 90°, the patient attempts to externally rotate against resistance supplied by the examiner. Infraspinatus tears result in pain and weakness. [Figure caption and citation for the preceding image starts]: External rotation testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
Lift-off test: evaluates the patient's ability to lift the hand away from the small of the back as the examiner applies resistance. The examiner must ensure the patient uses the shoulder and arm rather than wrist and fingers to perform this task. Weakness suggests a subscapularis tear. [Figure caption and citation for the preceding image starts]: Lift-off testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
Belly-press test: the patient presses the hand against the umbilicus with the elbow forward from the trunk. The examiner applies resistance by placing his or her hand between the patient's hand and abdomen. Inability to maintain elbow anterior to the coronal plane of the trunk suggests a subscapularis tear. This test may also be performed supine with the examiner stabilizing the scapula.[Figure caption and citation for the preceding image starts]: Belly-press testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
The patient should be actively pushing against the examiner's hand in all these tests. Muscle strength can be graded on a 0 to 5 scale. Weakness (0/5 to 3/5) suggests a rotator cuff tear.
Provocative impingement tests (Neer and Hawkins)
Typically positive with rotator cuff tears. The Neer impingement test can be performed with the patient seated or standing. The examiner keeps one hand on the patient's scapula to prevent rotation. As the patient's arm is elevated by the examiner, reproduction of pain is a positive test for impingement. With the Hawkins test, the patient's arm is positioned at 90° of elevation and the elbow is bent to 90°. The examiner places an internal rotation force on the patient's arm. Reproduction of pain is a positive test for subacromial inflammation and rotator cuff tendinopathy.
Subacromial injection with local anesthetic
The presence of pain and limited active motion, or signs of rotator cuff tendinopathy, warrants consideration of diagnostic subacromial injection with local anesthetic followed by re-examination. If the rotator cuff is intact, strength should improve after the pain-relieving injection.
Contribution of history and clinical tests to the diagnosis
Opinions differ on the importance of history and physical exam in diagnosing rotator cuff tear.[20]
One study of 103 patients with tears reported that the characteristics of the pain, the site of tenderness, and weakness to resisted abduction did not correlate with the presence or severity of the tear, although the extent of tear did relate to the limitation of shoulder abduction.[21] Similarly, one systematic review that evaluated two level IV studies (case control/cohort) found that historical findings (including reports of the presence or absence of pain at rest, pain during sleep, or pain during motion) did not help to identify patients with rotator cuff tear.[22] This systematic review also assessed the effect of physical examination maneuvers and found that a positive external rotation resistance test was among the most accurate findings for detecting rotator cuff disease. Positive results on provocative tests (Neer test and Hawkins test) did not appear to be helpful.[22]
In another systematic review that evaluated the sensitivity and specificity of five clinical tests, the Hawkins-Kennedy test, the Neer sign, and the empty can test were better for ruling out subacromial irritation (when the exam was normal) than ruling it in.[23] The drop arm test and the lift-off test had higher pooled specificities than sensitivities, and were more useful at ruling in rotator cuff tendinopathy if the test was positive.[23]
Of note, clinical maneuvers evaluated in published studies are typically performed by specialists on referred patients. It is uncertain whether examinations performed by generalists or primary care physicians would elicit the same results. As tests are refined and specificity for individual tendons is increased, the exam will likely have increasing influence on decision-making.[Figure caption and citation for the preceding image starts]: Neer impingement testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
[Figure caption and citation for the preceding image starts]: Hawkins impingement testFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
[Figure caption and citation for the preceding image starts]: Subacromial injection. Insert needle just inferior to posterior edge of acromion (x), aiming parallel to the undersurface of the acromionFrom the collection of Daniel J. Solomon, MD; used with permission [Citation ends].
Imaging
Radiographs are typically used during the initial evaluation to rule out fractures after trauma and to evaluate other pathology, such as acromioclavicular joint, glenohumeral arthritis, or rarely, a neoplasm. Clinicians must be aware that apical lung tumors (Pancoast tumor) may present with shoulder pain.[15][16]
Advanced imaging may be recommended if surgery is being contemplated or if a patient continues to have pain and decreased motion after at least 6 weeks of therapy.
Magnetic resonance imaging (MRI) and ultrasound are usually the advanced imaging modalities of choice to diagnose rotator cuff injury.[15][16] MRI is often preferred, as ultrasound is highly operator-dependent. MRI and ultrasound provide the surgeon with important information to permit better preoperative planning and establish realistic treatment expectations. The amount of retraction and atrophy, tear size, number of tendons involved, and presence of fatty infiltration are all important considerations in determining a treatment strategy. In particular, the sagittal oblique images provide excellent information regarding muscle quality and infiltrate. If available, magnetic resonance arthrography has been found to be more sensitive and specific than MRI and ultrasound (which are equivalent) in the diagnosis of rotator cuff tears.[15][24]
Computed tomography (CT) scan and CT arthrography are less commonly used, as further pathology can be more difficult to identify with these modalities. In addition, they subject the patient to appreciable ionizing radiation. However, they may be used if other imaging is not available. CT arthrograms have been shown to be comparable to MR arthrography in diagnosing full-thickness rotator cuff tears, but inferior to MR arthrography for diagnosing partial-thickness rotator cuff tears.[25]
Sensitivity and specificity of MRI utilized to detect full-thickness rotator cuff tears are 91% and 97%, respectively.[26]
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