Notes
2
Rotator Cuff Disease
Injuries to the rotator cuff are common orthopedic injuries and exist on a spectrum of disease that includes impingement, strains, partial or full thickness rotator cuff tears, massive rotator cuff tears (involvement of two or more tendons), and cuff tear arthropathy.1 The prevalence of rotator cuff disorders greatly increases with age, with abnormalities present in 9.7 percent of patients younger than twenty years old, 13 percent of those thirty to thirty-nine years old, 30 percent of sixty- to sixty-nine-year-olds, and 62 percent of patients over age eighty.2 Additional risk factors for sustaining a rotator cuff tear are hand dominance, smoking, hypercholesterolemia, manual or heavy labor, and a family history of rotator cuff tears.2-7
Anatomy
The rotator cuff consists of four muscles that contribute to the stability and motion of the shoulder joint: the supraspinatus, infraspinatus, teres minor, and subscapularis muscles. These muscles are innervated by nerves that arise from the brachial plexus, a network of nerves in the shoulder, from the contributions of the C5–T1 nerve roots, which provide sensory and motor innervation to the upper extremity (figure 2.1). First, the supraspinatus muscle originates from the supraspinous fossa of the superior aspect of the scapula and inserts on the greater tuberosity of the humerus. It functions in initiation of abduction of the shoulder from 0 to 15 degrees and then is accompanied by the deltoid to 90 degrees. Coactivation of the rotator cuff muscles and scapular rotation brings the shoulder motion up to 180 degrees of forward elevation. The infraspinatus muscle originates from the infraspinous fossa of the posterior aspect of the scapula and inserts on the greater tuberosity of the humerus, posterior and inferior to the insertion of the supraspinatus. It functions in external rotation of the shoulder. Both the supraspinatus and infraspinatus are innervated by the suprascapular nerve, which arises from the upper trunk of the brachial plexus and has contributions from the C5 and C6 nerve roots. The teres minor muscle originates from the lateral border of the scapula and inserts on the greater tuberosity of the humerus, below the insertion of the infraspinatus. It functions in external rotation of the shoulder when the arm is at 90 degrees of abduction and is innervated by the axillary nerve, which arises from the posterior cord of the brachial plexus. The subscapularis muscle originates from the subscapular fossa on the anterior aspect of the scapula and inserts on the lesser tuberosity of the humerus. It functions in internal rotation of the shoulder and is innervated by the upper and lower subscapular nerves, which also arise from the posterior cord of the brachial plexus.8
The function of the rotator cuff in creating dynamic stability to the shoulder joint is made possible by force coupling of the rotator cuff in the coronal and transverse planes.9,10 In the coronal plane, the superior moment from the deltoid muscle and supraspinatus is balanced by the inferior moment of the subscapularis, infraspinatus, and teres minor muscles. In the transverse plane, the anterior moment from the subscapularis muscle is balanced by the posterior moment of the infraspinatus and teres minor muscle. Rotator cuff tears alter this balance and equilibrium.
Pathophysiology
Broadly, injury to the rotator cuff can occur due to an acute, traumatic cause, or due to a chronic, degenerative cause.11,12 In younger patients, traumatic rotator cuff tears generally occur after a high-energy event, such as a fall or traction injury, and are associated with injuries such as a shoulder dislocation.12 In older patients, traumatic events remain a cause of rotator cuff tears, but degenerative mechanisms play a much larger role.13 Degenerative causes of rotator cuff tears can be broadly characterized as being extrinsic or intrinsic.13 The most notable extrinsic factor contributing to the development of degenerative rotator cuff pathology is acromial shape, as hooked, curved, and laterally sloped acromia are associated with the development of rotator cuff tears. While these extrinsic factors typically contribute to tears on the bursal of the rotator cuff, articular sided tears are more often due to intrinsic factors, such as those explored in the degeneration-microtrauma theory.14 Aging, poor vascularity, and repetitive microtrauma lead to inflammatory changes and oxidative stress in the rotator cuff tendon, which alter gene expression and lead to apoptosis.13,15 In an alternative neural theory of degeneration, overuse leads to overstimulation of the neurons of the rotator cuff, leading to pain, inflammation, and apoptosis in the tendon.13,16
History
Careful evaluation of a patient for a rotator cuff tear begins with the history.17,18 Patients with a rotator cuff tear most commonly present with pain around the shoulder (secondary to associated bursitis) and weakness with overhead activity, although other patients may be asymptomatic (if they have no active bursitis). The pain will typically be worse with overhead activities, lifting or carrying objects, or lying on the affected side. Further, other key elements of history include occupation and activity level; hand dominance; smoking status; and previous intervention including lifestyle changes, physical therapy, NSAIDs, corticosteroid injections, and surgical procedures. Lastly, a family history of rotator cuff tears should be determined.
Physical Examination
Next, a diagnosis of rotator cuff pathology requires a thorough physical examination through observation, palpation, and physical examination maneuvers. Both shoulders should be carefully inspected for symmetry, posture, and muscle bulk. There may be visible atrophy of the supraspinatus or infraspinatus fossae in chronic rotator cuff disease.17,19 Further, evidence of previous trauma or surgical scars on the skin should be noted. Patients with rotator cuff disease may present with tenderness to palpation along the insertion of the rotator cuff tendons on the greater and lesser tuberosities. Additionally, it is important to palpate adjacent structures, including the long head of the biceps tendon and the acromioclavicular joint. As the cervical spine is commonly a source of referred pain to the shoulder, a careful evaluation of the cervical spine with observation, palpation, active and passive range of motion, and provocative maneuvers, such as Spurling’s test, should be performed.20 Next, active and passive range of motion of the shoulder should be assessed. In the case of rotator cuff tears, active range of motion is typically diminished, while passive range of motion is maintained. Impingement signs may be present as well, as outlined in chapter 1.
Special Tests
Many physical examination maneuvers have been developed for further assessment of rotator cuff pathology. Certain tests are extremely sensitive and specific, while others may have less diagnostic accuracy. Advanced imaging is usually recommended to confirm the extent of rotator cuff pathology.21,22 First, the Jobe test is commonly performed in the evaluation of rotator cuff pathology (video 2.1; figure 2.2).17,18 The patient’s arms are placed in 90 degrees of abduction, angled forward 30 degrees, and internally rotated so that the thumbs face the floor. The examiner applies a downward force on the patient’s arm, and the patient is asked to resist this force. A positive test, which is indicated by pain or weakness during this maneuver, is suggestive of weakness of the supraspinatus muscle and/or concomitant subacromial impingement (video 2.2). Initiating the Jobe test is replicating part of the Neer sign maneuver, so there can be some crossover. Further, the drop arm test evaluates the integrity of the supraspinatus tendon. The examiner passively abducts the patient’s shoulder to 90 degrees and asks the patient to maintain the position. An inability to hold this position, resulting in the sudden dropping of the arm, indicates a positive test and suggests tearing of the supraspinatus (video 2.3).
Video 2.1: The Jobe Test. The examiner demonstrates the appropriate technique for the Jobe test on the patient’s right and left shoulders. The patient is seated on the examiner’s table. Both arms are placed in 90 degrees of abduction, angled forward 30 degrees, and internally rotated so that the thumbs face the floor. The examiner first applies a downward force to the patient’s left arm, asking the patient to resist the force and keep his arm level. The examiner then performs the same maneuver on the patient’s right arm.
Video 2.2: Jobe Test on the Right Shoulder. The examiner performs the Jobe test on the patient’s right shoulder. The test is considered positive if pain or weakness is elicited by the maneuver. A positive test indicates weakness of the supraspinatus muscle and/or subacromial impingement. The patient here is unable to resist the examiner’s downward applied force to his right shoulder, indicating weakness and a positive test result.
Video 2.3: Drop Arm Test. The examiner passively abducts the patient’s affected shoulder to 90 degrees and asks him to maintain this position. The patient is unable to do so, and his arm drops to the floor, indicating a positive test and tear of the supraspinatus.
Furthermore, the strength of the rotator cuff musculature, including the supraspinatus, infraspinatus, subscapularis, and teres minor, should be evaluated. Further examination of the infraspinatus muscle can be performed with the infraspinatus test (video 2.4).17,18 The patient’s arm is placed at the side in full adduction, and the elbow is placed in 90 degrees of flexion. The examiner applies a medially directed force to the arm, while asking the patient to externally rotate the shoulder against this resistance. A positive test result is pain and/or weakness with resisted external rotation and suggests a deficit of the infraspinatus.
Video 2.4: The Infraspinatus Test. The examiner performs the Infraspinatus Test on a patient with a rotator cuff tear. The patient is seated with the shoulders adducted and the elbow at 90 degrees of flexion. The examiner asks the patient to externally rotate their shoulder, while the examiner applies a medially directed force to the arm. A test is considered positive with pain or weakness with resisted external rotation. Here, the patient displays significant weakness of his left shoulder in external rotation, indicating a positive test result and deficit of the infraspinatus.
The external rotation lag sign is another physical examination maneuver performed to assess rotator cuff pathology, specifically to test the infraspinatus (video 2.5; figure 2.3).17,18 Initially, the patient’s shoulder is fully adducted, and the elbow is placed at 90 degrees of flexion. The examiner places the shoulder in maximal external rotation, and the patient is asked to hold this position. An inability to hold this position indicates weakness of the infraspinatus (video 2.6).
Video 2.5: The External Rotation Lag Sign." The examiner demonstrates the appropriate technique for the external rotation lag sign on the patient’s right shoulder. The patient is seated on the examiner’s table with the right shoulder fully adducted and the elbow at 90 degrees of flexion. The examiner places the patient’s right shoulder in maximal external rotation and asks them to maintain this position.
Video 2.6: The External Rotation Lag Sign." The examiner demonstrates the external rotation lag sign on a patient with a rotator cuff tear. A test is considered positive if the patient is unable to maintain the position of maximal external rotation and if the arm falls into internal rotation. A positive test is specific for full-thickness tears of the infraspinatus. Here, the patient is unable to maintain the position of maximal external rotation and the arm drifts into internal rotation. The test is positive.
The Hornblower’s sign is used to assess pathology of the teres minor (video 2.7; figure 2.4).17,18 The patient’s shoulder is placed in 90 degrees of abduction and 90 degrees of external rotation with the elbow also bent to 90 degrees, and the patient is asked to hold this position. The test is positive if the arm falls into internal rotation, assuming a position as if blowing a horn (video 2.8). A positive test result suggests tearing of the teres minor tendon.
Video 2.7: The Hornblower's Sign." The examiner demonstrates the proper technique for the Hornblower’s sign. The patient is seated on the examiner’s table. The patient’s right shoulder is placed in 90 degrees of abduction and 90 degrees of external rotation with the elbow also bent to 90 degrees. The examiner asks the patient to hold this position.
Video 2.8: The Hornblower's Sign. The examiner demonstrates the Hornblower’s sign on a patient with a rotator cuff tear. A test is considered positive if the patient is unable to maintain the shoulder in 90 degrees of abduction and 90 degrees of external rotation, and the arm falls into internal rotation. A positive test indicates a deficiency in the teres minor muscle. Here, the patient is unable to maintain the shoulder in 90 degrees of abduction and 90 degrees of external rotation when the examiner applies a downward directed force, indicating a positive test.
There are several tests to assess the integrity of the subscapularis, including the belly press test, lift off test, internal rotation lag sign, and bear hug test.17,18 Increased passive external rotation in the affected shoulder compared to the contralateral shoulder is suggestive of a subscapularis tear as well (video 2.9). When all these tests are used in conjunction with one another, the best diagnostic accuracy is achieved.
Video 2.9: Increased Passive External Rotation of the Shoulder. The examiner demonstrates the technique for examining passive external rotation of the shoulder. The patient is seated with his arm adducted and his elbow in 90 degrees of flexion. The examiner passively externally rotates both shoulders and compares the range of motion. An increase in passive external rotation in one shoulder compared to the contralateral shoulder is suggestive of a subscapularis tear. Here, the patient has increased passive external rotation in his right shoulder when compared to his normal left shoulder, which is suggestive of a right-sided subscapularis tear.
The belly press test is the most commonly used physical examination technique to assess the integrity of the subscapularis tendon (video 2.10; figure 2.5).17,18 The patient is asked to press the hand into the belly and internally rotate the shoulder against resistance. If the patient’s wrist flexes or they demonstrate weakness to resistance, then the test is deemed positive (video 2.11).
Video 2.10: The Belly Press Test. The examiner demonstrates the appropriate patient positioning for the belly press test on the patient’s right and left shoulders. The patient is seated on the examiner’s table. The patient’s shoulders are placed in internal rotation, his elbows are flexed to 90 degrees, and his palms are placed on his belly. The examiner asks the patient to press the hand into the belly and internally rotate the shoulder against resistance. The test is considered positive if the patient’s wrist flexes or they demonstrate weakness to resistance.
Video 2.11: The Belly Press Test. The examiner performs the belly press test on a patient with a rotator cuff tear. The test is considered positive if the patient’s wrist flexes or they demonstrate weakness to resistance. A positive test indicates a tear of the subscapularis tendon. Here, the patient is unable to internally rotate his shoulder while keeping the wrist straight. Further, the patient is unable to resist a posteriorly directed force by the examiner. The patient has a positive right-sided belly press test, indicating a right-sided subscapularis tear.
Next, the lift off test is performed with the patient positioning their hand behind the back at the level of the lumbar spine with the palm facing outward (video 2.12; figure 2.6).17,18 The patient is asked to lift their hand off their back. Weakness in response to resistance or inability to perform such a motion indicates a positive test, which is suggestive of deficiency of the subscapularis (video 2.13). This test may be difficult for a patient to perform with a stiff shoulder and internal rotation is limited due to glenohumeral arthritis, adhesive capsulitis, or severe pain from impingement. In addition, elbow extension from the triceps can give a false negative.
Video 2.12: The Lift Off Test. The examiner demonstrates the appropriate technique for the lift off test on the patient’s right shoulder. The patient positions his hand behind his back at the level of the lumbar spine with the palm facing outward. The patient is asked to internally rotate his shoulder to lift his hand off his lumbar spine. The test is negative if the patient is able to successfully lift his hand off his lumbar spine.
Video 2.13: The Lift Off Test. The examiner performs the lift off test on the patient’s right and left shoulders. The test is considered positive if the patient is unable to internally rotate either shoulder and lift their hands off the back or if the patient cannot actively resist the gentle force applied by the examiner. A positive test indicates a deficit of the subscapularis. Here, the patient successfully lifts off her right hand but is unable to lift off her left hand. The patient has a positive left-sided lift off test.
The internal rotation lag sign (video 2.14) is performed by placing the patient’s hand in maximal internal rotation with their hand elevated several centimeters off of the lumbar spine.9,17,18 The patient is instructed to maintain this position. Failure to actively maintain this position (with the hand falling toward the patient’s body) indicates a positive test, and deficit of the subscapularis.
Video 2.14: The Internal Rotation Lag Sign. The examiner performs the internal rotation lag sign on a patient with a subscapularis tear. The patient’s hand is placed behind his back at the level of the lumbar spine. The patient’s shoulder is passively placed in maximal internal rotation by the examiner with the patient’s hand several centimeters posterior to the lumbar spine, and the patient is asked to maintain this position away from the body. A positive test is indicated by failure to actively maintain this position and indicates a deficit of the subscapularis. Here, the patient has a positive right-sided internal rotation lag sign, but a negative left-sided internal rotation lag sign.
The last provocative maneuver discussed for subscapularis function is the bear hug test (figure 2.7; video 2.15). The hand of the affected shoulder is placed on the contralateral shoulder with the fingers extended and the elbow at 90 degrees. The patient is instructed to hold this position while the examiner applies an external rotation force to the patient’s arm. A test is positive when the patient cannot maintain this position.
Video 2.15: The Bear Hug Test. The examiner demonstrates the bear hug test on a patient’s right shoulder. The patient’s elbow is bent to ninety degrees and the palm rests on his contralateral shoulder. The examiner applies an external rotation force to the patient’s right arm. A test is positive if the patient can not maintain this position. Here, the test is negative, indicating an intact subscapularis.
Sensitivities and specificities for all examinations described in this chapter are outlined in table 2.1.21,23-25
| Test | Sensitivity | Specificity |
|---|---|---|
| Jobe Test21 | 88% | 62% |
| Drop Arm Test21 | 21% | 96% |
| Infraspinatus Test21,25 | 90% | 74% |
| External Rotation Lag Sign21,24 | 97% | 93% |
| Hornblower Sign21 | 17% | 96% |
| Belly Press Test23 | 28% | 87% |
| Lift Off Test23 | 22% | 94% |
| Internal Rotation Lag Test23.24 | 32% | 92% |
| Bear Hug Test23 | 55% | 94% |
Key Terminology
Physical examination technique used to assess the integrity of the subscapularis tendon. The hand of the patient’s affected shoulder is placed on the contralateral shoulder with the fingers extended and the elbow at 90 degrees. The patient is instructed to hold this position while the examiner applies an external rotation force to the patient’s arm. A test is positive when the patient cannot maintain this position. ↵
Physical examination technique used to assess the integrity of the subscapularis tendon. The patient is asked to press the hand into the belly and internally rotate the shoulder against resistance. A test is positive if the patient’s wrist flexes or they demonstrate weakness to resistance. ↵
Physical examination maneuver performed to assess rotator cuff pathology, specifically to test the infraspinatus. Initially, the patient’s shoulder is fully adducted and the elbow is placed at 90 degrees of flexion. The examiner places the shoulder in maximal external rotation, and the patient is asked to hold this position. An inability to hold this position indicates a positive test result. ↵
Physical examination maneuver used to assess pathology of the teres minor of the rotator cuff. The patient’s shoulder is placed in 90 degrees of abduction and 90 degrees of external rotation with the elbow also bent to 90 degrees, and the patient is asked to hold this position. The test is positive if the arm falls into internal rotation, assuming a position as if blowing a horn. ↵
A test for the assessment of subacromial impingement and/or rotator cuff (supraspinatus) pathology. The patient’s arms are placed in 90 degrees of abduction, angled forward 30 degrees, and internally rotated so that the thumbs face the floor. The examiner applies a downward force to the patient’s arm, asking the patient to resist the force and keep their arm level. A positive test is noted if pain and/or weakness is elicited by the maneuver. ↵
Rotator cuff muscle that originates from the infraspinous fossa of the posterior aspect of the scapula and inserts on the greater tuberosity of the humerus, posterior and inferior to the insertion of the supraspinatus. It functions in the external rotation of the shoulder. ↵
An examination of the infraspinatus of the rotator cuff. The patient’s arm is placed at the side in full adduction, and the elbow is placed in 90 degrees of flexion. The examiner applies a medially directed force to the arm, while asking the patient to externally rotate the shoulder against this resistance. A positive test is pain and/or weakness with resisted external rotation. ↵
Physical examination maneuver used to assess the subscapularis of the rotator cuff. The test is performed by placing the patient’s hand in maximal internal rotation and elevated several centimeters off of the lumbar spine. The patient is instructed to maintain this position. A positive test result is indicated by failure to actively maintain this position (with the hand falling toward the patient’s body). ↵
Physical examination maneuver used to assess the subscapularis of the rotator cuff. The test is performed with the patient positioning both hands behind their back at the level of the lumbar spine with the palms facing outward. The patient is asked to lift their hands off their back. A test is positive if there is weakness to resistance or inability to perform such a motion. ↵
Group of four muscles and their associated tendons, including the supraspinatus, infraspinatus, teres minor, and subscapularis, which help to stabilize the humeral head in the glenoid fossa and move the humerus in several planes. ↵
Rotator cuff muscle that originates from the subscapular fossa on the anterior aspect of the scapula and inserts on the lesser tuberosity of the humerus. Functions in internal rotation of the shoulder. ↵
Rotator cuff muscle that originates from the supraspinous fossa of the superior aspect of the scapula and inserts on the greater tuberosity of the humerus. It functions in the abduction of the shoulder. ↵
Rotator cuff muscle that originates from the lateral border of the scapula and inserts on the greater tuberosity of the humerus, below the insertion of the infraspinatus. It functions in the external rotation of the shoulder when the arm is at 90 degrees of abduction. ↵
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