22. | Manual of Rheumatology and Outpatient Orthopedic Disorders (LB Spiral Manuals)

Chapter 15 Shoulder Pain

Manual of Rheumatology and Outpatient Orthopedic Disorders

Chapter 15 Shoulder Pain

Russell F. Warren

Anatomy and function
Types of pain
Physical examination
Radiographs
Common shoulder problems

The diagnosis and treatment of problems of the shoulder region require an understanding of the anatomy and function of this joint.

I. Anatomy and function. The shoulder consists of three joints and two gliding planes, which allow an exceedingly large range of motion at the expense of glenohumeral stability. As a result, the glenohumeral joint is the most commonly dislocated joint in the body. The gliding planes consist of the scapulothoracic surface and the subacromial space. The three joints are the acromioclavicular, sternoclavicular, and glenohumeral articulations. Elevation of the arm is produced by the combined rotation between the scapula and chest wall as well as by the glenohumeral joint. The rotator cuff consists of four muscles: the supraspinatus, the infraspinatus, the teres minor, and the subscapularis. In addition to assisting in internal and external rotation, these muscles act as a depressor on the humeral head during shoulder elevation. In this manner, a fulcrum that allows the deltoid to elevate the arm is established. As long as some depressor action of the rotator cuff remains, surprisingly large tears of the rotator cuff may be compatible with full elevation of the arm.

II. Types of pain. Pain may be related to intrinsic lesions of the shoulder, or it may be referred from other sites.

Cervical spondylosis of C5 “6 often results in a referred type of pain to the shoulder. If the radiculopathy includes weakness of shoulder abduction and external rotation, it may closely mimic a torn rotator cuff. Cervical types of shoulder pain are usually increased by neck motion, particularly extension with rotation to the involved side.
More than one basis for pain may be present; for example, in patients with cervical spondylosis and referred pain to the shoulder, limitation of shoulder motion secondary to adhesive capsulitis may also develop (see section C.2 ). Also, pain can be referred from diseases involving the heart, lung, or gall bladder.
Intrinsic shoulder pain is generally worse at night and is increased by lying on the shoulder. Shoulder motion will generally aggravate the pain, particularly full elevation in the forward flexed position or abduction to 90 degrees. Tears of the rotator cuff may also cause pain radiating into the forearm and, rarely, the hand. Specific problems of the shoulder region tend to occur at certain age intervals.
1. From ages 20 to 30 years , the impingement syndrome and instability problems may present as a painful shoulder.
2. From ages 40 to 50 years, the impingement syndrome, calcific tendinitis, and adhesive capsulitis become more common.
3. From ages 50 to 70 years, the impingement syndrome may progress to a full- thickness rotator cuff tear. In addition, adhesive capsulitis is common. Degenerative lesions of the acromioclavicular, sternoclavicular, and occasionally the glenohumeral joints become more frequent. Pain from metastatic disease should be considered .

III. Physical examination. On examining the shoulder region, one should note that the musculature of the dominant extremity may be somewhat hypertrophied about the shoulder and arm, particularly in athletic persons.

Observation
1. The position of the shoulder relative to the contralateral side should be noted. Elevation or dependency of the shoulder may be related to scoliosis, Sprengel's deformity, or simply athletic activity.
2. Swelling about the shoulder may be secondary to inflammation of a bursa or associated with rotator cuff tears.
3. View the shoulder from both the anterior and posterior aspects. Observe the range of motion from behind as the arm is elevated to note the scapulohumeral rhythm.
4. Specific muscle atrophy may indicate either rotator cuff tears or neurologic involvement.
Palpation
1. The supraclavicular fossa should be carefully palpated for masses as well as for tenderness of the brachial plexus, which is seen in thoracic outlet syndrome.
2. Local tender spots indicative of trigger points should be sought along the interscapular region and overlying musculature of the shoulder. If pressure is applied to these spots, radiation of pain into the upper arm may be observed .
3. Specific sites of tenderness should be noted anteriorly over the biceps tendon and laterally over the subdeltoid bursa and rotator cuff.
4. The acromioclavicular and sternoclavicular joints should be carefully examined for tenderness.
Motion
1. In examining the shoulder, one should observe the full range of active and passive motion, noting any discrepancy such as that sometimes seen in a rotator cuff tear. Active elevation in the plane of the scapula may demonstrate altered scapular thoracic rhythm with a shrug sign if a rotator cuff tear is present.
2. Shoulder motion is recorded as abduction in degrees and forward flexion in degrees. External rotation of the humerus is noted with the arm at the side as well as in the abducted position of 90 degrees. Internal rotation is recorded by placing the hand behind the back and noting which spinous process the thumb will reach. It is also tested at 90 degrees of abduction.
3. The impingement sign is positive in patients with rotator cuff inflammation and is noted by flexing the arm forward to the full overhead position. Pain is present during the last 10 degrees of passive elevation. Passive abduction to the 90-degree position with internal rotation will similarly produce pain.
4. The adduction test consists of fully adducting the humerus across the chest. This test stresses the acromioclavicular joint and will cause pain if degeneration of the joint is present. Placing the arm in adduction and resisting elevation may be painful if a slap lesion is present ( superior labral tear).
5. In cases in which instability of the glenohumeral joint is a possibility, the joint should be carefully stressed in the following manner: The patient is placed in the supine position, and after maximal muscle relaxation is achieved, the shoulder is adducted and internally rotated with pressure placed in the posterior direction. If posterior instability is present, a click or a clear subluxation may be noted during this maneuver. To evaluate anterior instability, the shoulder is placed in the abducted, externally rotated position with gentle pressure placed in an anterior direction behind the humeral head. In some patients, inferior instability is demonstrated by distracting the arms inferiorly to see if a sulcus forms (sulcus sign) distal to the acromion. This sign is frequently present in multidirectional instability.
Neurovascular examination
1. A complete neurologic examination should be performed. Weakness may be the result of intrinsic shoulder lesions, as in a cuff tear, or of nerve lesions of the brachial plexus or cervical roots. Strength testing at 0 degrees and 90 degrees of elevation is important. Weakness of external rotation with the arm at the side is present with large rotator cuff tears involving the infraspinatus or with C5 “6 nerve root problems. The lift-off test for subscapularis tears is performed by placing the back of the hand over L-5 and pushing away from the back. Loss of strength is associated with subscapularis tears.
2. The pain of a carpal tunnel syndrome may be referred proximally to the shoulder region.
3. Because thoracic outlet syndrome may be present, the circulation of the arm and the hand must be carefully evaluated.
  1. Adson's test, which may be positive, consists of palpating the radial pulse while the patient's head is turned to the involved side and performing a Valsalva maneuver. A positive test result ”a decrease in the pulse ”is not diagnostic; it occurs in a significant percentage of asymptomatic subjects. A reduced radial pulse on testing should be compared with the pulse on the contralateral side. It is better to test with the arm abducted and externally rotated, noting any decrease in the pulse. In addition, the Roos test is useful. This test is performed with patients in a similar position, but they open and close their hands for 1 to 2 minutes in an attempt to reproduce their symptoms.
  2. In the arterial type of thoracic outlet syndrome, auscultation of the supraclavicular region may demonstrate a bruit with the arm in position. The blood pressure may also be significantly reduced in the abducted position.

IV. Radiographs

Standard views of the shoulder generally have included internal and external rotation. Although helpful in the diagnosis of calcific tendinitis, they provide little information regarding the anteroposterior alignment of the shoulder or the width of the glenohumeral joint. Because the scapula lies on the chest wall at approximately a 40-degree angle, radiographs should be taken at a right angle to the scapula and glenohumeral joint rather than to the chest.
Lateral and axillary views of the scapula are useful in identifying degenerative changes of the glenohumeral joint and calcification of the rotator cuff; they are particularly important in the evaluation of acute injuries to the shoulder.

V. Common shoulder problems. The most common shoulder problems are impingement syndrome with rotator cuff tears, calcific tendinitis, adhesive capsulitis, acromioclavicular joint pain, thoracic outlet syndrome, and shoulder instability.

Impingement syndrome generally develops during the fifth decade and may progress to a rotator cuff tear by age 55. The underlying pathology consists of degeneration of the tendons of the rotator cuff. As a result, the insufficient cuff fails to prevent superior migration of the humeral head during elevation. This results in pressure on the rotator cuff and increasing pressure on the bone. Spurs may develop within the coracoacromial ligament over time with cuff degeneration. In some patients, a hooked acromion will increase the pressure on the cuff.
1. In young patients, cuff injury secondary to a contusion may occur, with hemorrhage and edema decreasing cuff function. This can mimic a tear. In addition, secondary impingement may develop in the second and third decades in throwing athletes . This happens when an underlying instability is present.
  1. Pain is generally noted with overhead elevation at 90 degrees with rotation. The pain may increase during specific activities, such as throwing and swimming.
  2. The impingement sign may be positive and the impingement test will relieve pain. The radiographic findings of young patients are often negative, but magnetic resonance imaging (MRI) may show cuff degeneration with a partial tear of the articular side of the supraspinatus and labral injury in some.
  3. Treatment is based on activity modifications and temporary avoidance of the offending positions .
    1. Any contractures about the shoulder region must be eliminated by a stretching program.
    2. Oral antiinflammatory agents may be helpful, particularly 25 mg of indomethacin four times daily for 7 to 10 days.
    3. A muscle-strengthening program of exercise must be established because shoulder pain often leads to weakness, particularly of the rotator cuff. In carrying out these exercises, the patient should avoid the pain-producing positions.
    4. A subacromial injection of 40 mg of methylprednisolone acetate (Depo-Medrol) is administered if the previous methods have failed, but injections should be limited to one or two during a 3-month period.
    5. After 6 months, if there is no improvement, arthroscopy with cuff debridement, followed by physical therapy , may be of value. If instability is present, it needs to be addressed with capsular plication or arthroscopic heating of the capsule . This will shrink the ligaments about 15%. This technique is experimental but to date has been useful in a limited number of patients involved in throwing or swimming sports activities.
2. During the fourth or fifth decade, a similar picture is noted, particularly in middle-aged tennis players, who often complain of pain while serving or hitting an overhead shot.
  1. Radiography may show some sclerosis of the greater tuberosity or of the acromion. MRI may show a partial or complete cuff tear.
  2. Treatment is similar to that in the older age groups.
3. During the sixth or seventh decade, further rotator cuff degeneration develops as a result of decreased vascularity of the supraspinatus tendon.
  1. The rotator cuff becomes attenuated as well as degenerative, with subsequent partial tearing that may progress to full-thickness tearing in some patients.
  2. The findings are similar to those of the younger patient but increased in severity. Crepitation of the subacromial space from an inflamed, thickened subacromial bursa may be present. In this age group , biceps tendinitis and subacromial bursitis are rarely separate entities and form part of the impingement syndrome.
  3. Atrophy of the infraspinatus and supraspinatus regions will increase in severity, particularly if a cuff tear is developing.
  4. When a small tear of the rotator cuff is present, shoulder motion may initially be normal, but as the tear increases , elevation will gradually be replaced by a shoulder-shrugging movement.
  5. Loss of external rotation may develop; however, it is seen only in patients with large, extensive tears that involve both the supraspinatus and infraspinatus.
  6. In patients with large tears of the rotator cuff, a drop sign will be positive. This sign is elicited by having the patient elevate the arm either actively or passively into the full overhead position, then lowering it in the place of the scapula. At approximately the 90-degree position, marked weakness is noted, and the arm will drop 30 to 40 degrees, often with pain.
  7. Shoulder radiographs will demonstrate sclerosis of the acromion with a reversal of the normal convexity of the inferior surface of the acromion.
    1. Occasionally, a large spur will develop at the anterior inferior edge of the acromion in the coracoacromial ligament. An outlet radiograph of the shoulder may demonstrate the spur, a curved acromion, or both.
    2. If a cuff tear is suspected or if the patient does not respond to treatment, an MRI should be obtained, which will demonstrate cuff degeneration and a tear if present. Tear size can be noted in addition to the degree of retraction and muscle atrophy.
    3. For older patients, surgical treatment consists of acromioplasty and, if a tear is present, rotator cuff repair.
  8. The conservative treatment of older patients is similar to that of younger patients unless a rotator cuff tear is obvious.
    1. Stretching, strengthening, and antiinflammatory agents can often be beneficial.
    2. Injection of the subacromial space on one or two occasions may be helpful in allowing the patient to restore shoulder function; a long, repeated course of injections, however, will lead to further degenerative changes of the rotator cuff.
Calcific tendinitis may be present in either an acute or chronic form.
1. In the acute process, the patient notes the sudden occurrence of severe shoulder pain and will present holding the arm carefully at the side to avoid all shoulder movement.
  1. A distinct swelling may be seen overlying the humeral head, and gentle palpation reveals a well-localized area of extreme tenderness.
  2. All movements of the shoulder are resisted by pain.
  3. Shoulder radiographs will generally show a fluffy calcific deposit within the rotator cuff tendons, most commonly the supraspinatus.
  4. Treatment of the acute situation consists of injecting the deposit with 2 to 3 mL of 1% lidocaine and 40 mg of methylprednisolone acetate. After some local anesthesia is achieved, the deposit should be needled in an attempt to break it up, thus allowing the deposit to migrate into subacromial bursae, where it will be absorbed. Occasionally, the calcific deposit will rupture spontaneously, with prompt resolution of the patient's pain.
    1. Because pain may be temporarily increased following injection of the calcium deposit, ice should be applied to the shoulder for 20 to 30 minutes on several occasions during the next 24 hours.
    2. In addition, indomethacin is given for 3 to 4 days at a dosage of 25 mg four times daily.
    3. When pain abates, full shoulder motion should be encouraged to avoid development of a contracture.
2. In the chronic situation, the calcific deposit becomes indurated within the rotator cuff.
  1. There is a long history, often of multiple attacks of shoulder pain. Complaints will often mimic those of the impingement-type syndromes.
  2. Treatment is similar to that of acute tendinitis. Oral antiinflammatory agents (75 mg of sustained-release indomethacin twice daily for 7 days) and exercises are prescribed. Injections of 40 mg of methylprednisolone acetate are administered if no improvement is seen following conservative management. If pain persists or repeated attacks occur, operative removal of the calcium may be required.
  3. It should be noted that some patients 40 years of age or more have asymptomatic calcium deposits in the shoulder.
Adhesive capsulitis (frozen shoulder), frequently seen during the fifth and sixth decades, may develop as a result of intrinsic shoulder pathology or occur secondary to extrinsic causes, particularly cervical spondylosis. Often, no specific etiologic factor can be found.
1. Motion will generally be restricted to elevation of 90 degrees, external rotation of 0 degrees, and a loss of internal rotation. Pain is present, particularly at the extremes of motion and at night.
2. On occasion, a large loss of shoulder motion will develop so slowly that the patient is unaware of the magnitude of the problem. Conversely, the onset may be sudden and severe, with marked loss of glenohumeral motion and a restriction of abduction to the 90-degree range.
3. Tenderness is present but poorly localized.
4. A history of diabetes is frequently obtained.
5. Radiographic findings will often be negative in the early stage but with time will show osteoporosis.
6. The region of the cervical spine, as well as chest and diaphragmatic lesions, should be carefully considered. Complete radiographic evaluation, including cervical spine, chest, and shoulder views, may be required.
7. Metastatic lesions involving the shoulder, spine, or brachial plexus may present as an adhesive capsulitis.
8. Therapy is directed toward achieving an improved range of motion. Steroid injections in the joint and oral antiinflammatory agents may be useful, depending on the stage of disease. A vigorous program of physical therapy is instituted both actively and passively at home and with a therapist. Improvement in range of motion is variable, but 95% of patients show significant, but slow, improvement by 3 months. If improvement does not occur, arthroscopic capsular release has been useful in a number of patients.
Acromioclavicular joint. Pain secondary to pathology of the acromioclavicular joint is frequently overlooked. The joint lies directly over the rotator cuff, and thus any alterations of the inferior surface will result in inflammation of the supraspinatus tendon deep to this joint.
1. Degenerative lesions of this joint may result in thickening and swelling and create an impingement syndrome.
2. Pain will occur with overhead activity of the arm and be aggravated by adduction of the arm across the chest. Pain occurs at night and is often increased by lying on the shoulder.
3. Tenderness is well localized to the involved joint.
4. Radiographs demonstrate narrowing of the joint with sclerosis and marginal osteophytes. Specific views taken at a 15-degree cephalic tilt allow better visualization of the acromioclavicular joint.
5. Therapy of the chronic situation consists of antiinflammatory medication , lidocaine injected locally, and Depo-Medrol. The degree of relief obtained from these injections confirms the diagnosis.
  1. In the posttraumatic condition, muscle-strengthening exercises, particularly for the deltoid and trapezius, will result in improvement if significant degenerative changes are not present.
  2. In the chronic situation in which pain persists despite one or two injections, resection of the outer 2 cm of the clavicle may be warranted.
Subluxation of the shoulder is an important cause of pain in the younger population. Often, the patient will state that the shoulder comes out, although some patients will complain only of shoulder pain, particularly in the posterior humeral region.
1. Specific testing for shoulder instability should be performed, and any positions associated with apprehension should be noted.
2. Radiographic evaluation may provide confirmatory evidence of shoulder instability.
3. In those patients who have subluxation of the shoulder without dislocation, rotation exercises may be helpful. If symptoms persist despite this approach, surgical stabilization may be required.
Additional shoulder conditions. Although the more common causes of shoulder pain have been discussed, a wide variety of conditions may affect the shoulder.
1. The thoracic outlet syndrome with vascular or brachial plexus involvement may be the basis for extremity pain or fatigue.
2. Any type of arthropathy, including rheumatoid arthritis, degenerative joint disease, and syndromes such as polymyalgia rheumatica, may be expressed as rheumatic shoulder pain; however, in contrast to the conditions reviewed in this chapter, such problems are part of more generalized rheumatic syndromes.
3. Osteonecrosis (avascular necrosis) commonly affects the humeral head and should be considered in the differential diagnosis of shoulder pain (see Chapter 45).
4. The shoulder-hand syndrome (reflex sympathetic dystrophy), a poorly understood and uncommon basis for shoulder pain, is associated with diffuse swelling, pain, and vasomotor changes in the distal upper extremity (see Chapter 53). The problem occurs in elderly subjects and is sometimes related to myocardial infarction or other cardiopulmonary conditions. Unless an exercise program is vigorously instituted, supported by the use of analgesics and antiinflammatory drugs, adhesive capsulitis may be the outcome. If agents such as indomethacin (100 to 150 mg/24 h) do not control pain sufficiently to permit exercise, a short course of prednisone (25 mg/24 h for 3 to 4 days) may be instituted.
5. A variety of intrathoracic problems (including coronary ischemia, pulmonary embolus, pleuritis, and pneumonitis) and diaphragmatic irritation from abdominal lesions should be considered in the differential diagnosis of pain referred to the shoulder region.

Books@Ovid
Copyright 2000 by Lippincott Williams & Wilkins
Stephen A. Paget, M.D., Allan Gibofsky, M.D., J.D. and John F. Beary, III, M.D.
Manual of Rheumatology and Outpatient Orthopedic Disorders

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