The Painful Shoulder: Part I. Clinical Evaluation

Family physicians need to understand diagnostic and treatment strategies for common causes of shoulder pain. We review key elements of the history and physical examination and describe maneuvers that can be used to reach an appropriate diagnosis. Examination of the shoulder should include inspection, palpation, evaluation of range of motion and provocative testing. In addition, a thorough sensorimotor examination of the upper extremity should be performed, and the neck and elbow should be evaluated.

Shoulder pain is a common complaint in family practice patients. The unique anatomy and range of motion of the glenohumeral joint can present a diagnostic challenge, but a proper clinical evaluation usually discloses the cause of the pain.

Anatomy

The shoulder is composed of the humerus, glenoid, scapula, acromion, clavicle and surrounding soft tissue structures. The shoulder region includes the glenohumeral joint, the acromioclavicular joint, the sternoclavicular joint and the scapulothoracic articulation (Figure 1a). The glenohumeral joint capsule consists of a fibrous capsule, ligaments and the glenoid labrum. Because of its lack of bony stability, the glenohumeral joint is the most commonly dislocated major joint in the body. Glenohumeral stability is due to a combination of ligamentous and capsular constraints, surrounding musculature and the glenoid labrum. Static joint stability is provided by the joint surfaces and the capsulolabral complex, and dynamic stability by the rotator cuff muscles and the scapular rotators (trapezius, serratus anterior, rhomboids and levator scapulae).

FIGURE 1A.

Anatomy of the shoulder girdle.

The rotator cuff is composed of four muscles: the supraspinatus, infraspinatus, teres minor and subscapularis (Figure 1b). The subscapularis facilitates internal rotation, and the infraspinatus and teres minor muscles assist in external rotation. The rotator cuff muscles depress the humeral head against the glenoid. With a poorly functioning (torn) rotator cuff, the humeral head can migrate upward within the joint because of an opposed action of the deltoid muscle.

FIGURE 1B.

The muscles of the rotator cuff.

Scapular stability collectively involves the trapezius, serratus anterior and rhomboid muscles. The levator scapular and upper trapezius muscles support posture; the trapezius and the serratus anterior muscles help rotate the scapula upward, and the trapezius and the rhomboids aid scapular retraction.

History

A complete history begins with the patient's age, dominant hand and sport or work activity. It is important to assess whether the injury prevents or hampers normal work activities, hobbies and sports. The patient should be asked about shoulder pain, instability, stiffness, locking, catching and swelling. Stiffness or loss of motion may be the major symptom in patients with adhesive capsulitis (frozen shoulder), dislocation or glenohumeral joint arthritis. Pain with throwing (such as pitching a baseball) suggests anterior glenohumeral instability. Patients who complain of generalized joint laxity often have multidirectional glenohumeral instability.

Distinguishing between an acute and a chronic problem is diagnostically helpful (Table 1). For example, a history of acute trauma to the shoulder with the arm abducted and externally

rotated strongly suggests shoulder subluxation or dislocation and possible glenoid labral injury. In contrast, chronic pain and loss of passive range of motion suggest frozen shoulder or tears of the rotator cuff.

TABLE 1 Key Findings in the History and Physical Examination

Finding Probable diagnosis Scapular winging, trauma, recent viral illness Serratus anterior or trapezius

dysfunction Seizure and inability to passively or actively rotate affected arm externally

Posterior shoulder dislocation

Supraspinatus/infraspinatus wasting Rotator cuff tear; suprascapular nerve entrapment

Pain radiating below elbow; decreased cervical range of motion

Cervical disc disease

Shoulder pain in throwing athletes; anterior glenohumeral joint pain and impingement

Glenohumeral joint instability

Pain or clunking sound with overhead motion Labral disorder Nighttime shoulder pain Impingement Generalized ligamentous laxity Multidirectional instability

Once the location, quality, radiation, and aggravating and relieving factors of the shoulder pain have been established, the possibility of referred pain should be excluded. Neck pain and pain that radiates below the elbow are often subtle signs of a cervical spine disorder that is mistaken for a shoulder problem.

The patient should be asked about paresthesias and muscle weakness. Pneumonia, cardiac ischemia and peptic ulcer disease can present with shoulder pain. A history of malignancy raises the possibility of metastatic disease. The patient should be asked about previous corticosteroid injections, particularly in the setting of osteopenia or rotator cuff tendon atrophy.

Physical Examination

A complete physical examination includes inspection and palpation, assessment of range of motion and strength, and provocative shoulder testing for possible impingement syndrome and glenohumeral instability. The neck and the elbow should also be examined to exclude the possibility that the shoulder pain is referred from a pathologic condition in either of these regions.

INSPECTION

The physical examination includes observing the way the patient moves and carries the shoulder. The patient should be properly disrobed to permit complete inspection of both shoulders. Swelling, asymmetry, muscle atrophy, scars, ecchymosis and any venous distention should be noted. Deformity, such as squaring of the shoulder that occurs with anterior dislocation, can immediately suggest a diagnosis. Scapular winging, which can be

associated with shoulder instability and serratus anterior or trapezius dysfunction, should be noted. Atrophy of the supraspinatus or infraspinatus should prompt a further work-up for such conditions as rotator cuff tear, suprascapular nerve entrapment or neuropathy.

PALPATION

Palpation should include examination of the acromioclavicular and sternoclavicular joints, the cervical spine and the biceps tendon. The anterior glenohumeral joint, coracoid process, acromion and scapula should also be palpated for any tenderness and deformity.

RANGE-OF-MOTION TESTING

Because the complex series of articulations of the shoulder allows a wide range of motion, the affected extremity should be compared with the unaffected side to determine the patient's normal range. Active and passive ranges should be assessed. For example, a patient with loss of active motion alone is more likely to have weakness of the affected muscles than joint disease.

Shoulder abduction involves the glenohumeral joint and the scapulothoracic articulation. Glenohumeral motion can be isolated by holding the patient's scapula with one hand while the patient abducts the arm. The first 20 to 30 degrees of abduction should not require scapulothoracic motion. With the arm internally rotated (palm down), abduction continues to 120 degrees. Beyond 120 degrees, full abduction is possible only when the humerus is externally rotated (palm up).

The Apley scratch test is another useful maneuver to assess shoulder range of motion (Figure 2). In this test, abduction and external rotation are measured by having the patient reach behind the head and touch the superior aspect of the opposite scapula. Conversely, internal rotation and adduction of the shoulder are tested by having the patient reach behind the back and touch the inferior aspect of the opposite scapula. External rotation should be measured with the patient's arms at the side and elbows flexed to 90 degrees.

FIGURE 2.

Apley scratch test. The patient attempts to touch the opposite scapula to test range of motion of the shoulder. (Left) Testing abduction and external rotation. (Right) Testing adduction and internal rotation.

EVALUATING THE ROTATOR CUFF

In evaluating the rotator cuff, the patient's affected extremity should always be compared with the unaffected side to detect subtle differences in strength and motion. A key finding, particularly with rotator cuff problems, is pain accompanied by weakness. True weakness should be distinguished from weakness that is due to pain. A patient with subacromial bursitis with a tear of the rotator cuff often has objective rotator cuff weakness caused by pain when the arm is positioned in the arc of impingement. Conversely, the patient will have normal strength if the arm is not tested in abduction.1

The supraspinatus can be tested by having the patient abduct the shoulders to 90 degrees in forward flexion with the thumbs pointing downward. The patient then attempts to elevate the arms against examiner resistance (Figure 3). This is often referred to as the empty can test.

FIGURE 3.

Supraspinatus examination (empty can test). The patient attempts to elevate the arms against resistance while the elbows are extended, the arms are abducted and the thumbs are pointing downward.

Next, with the patient's arms at the sides, the patient flexes both elbows to 90 degrees while the examiner provides resistance against external rotation (Figure 4). This maneuver is used to evaluate the function of the infraspinatus and teres minor muscles, which are mainly responsible for external rotation.

FIGURE 4.

Infraspinatus/teres minor examination. The patient attempts to externally rotate the arms against resistance while the arms are at the sides and the elbows are flexed to 90 degrees.

Subscapularis function is assessed with the lift-off test. The patient rests the dorsum of the hand on the back in the lumbar area. Inability to move the hand off the back by further internal rotation of the arm suggests injury to the subscapularis muscle.2 In one study, the investigators noted that only a few of the patients with confirmed subscapularis ruptures actually demonstrated a positive result on the lift-off test; the remainder could not complete the test because of pain.3

A modified version of the lift-off test is useful in a patient who cannot place the hand behind the back. In this version, the patient places the hand of the affected arm on the abdomen and resists the examiner's attempts to externally rotate the arm.

Provocative Testing

Provocative tests provide a more focused evaluation for specific problems and are typically performed after the history and general examination have been completed (Table 2).

TABLE 2 Tests Used in Shoulder Evaluation and Significance of Positive Findings

Test Maneuver Diagnosis suggested by positive result

Apley scratch test

Patient touches superior and inferior aspects of opposite scapula

Loss of range of motion: rotator cuff problem

Neer's sign Arm in full flexion Subacromial impingement Hawkins' test Forward flexion of the shoulder to 90

degrees and internal rotation Supraspinatus tendon impingement

Drop-arm test Arm lowered slowly to waist Rotator cuff tear Cross-arm test Forward elevation to 90 degrees and active

adduction Acromioclavicular joint arthritis

Spurling's test Spine extended with head rotated to affected shoulder while axially loaded

Cervical nerve root disorder

Test Maneuver Diagnosis suggested by positive result

Apprehension test

Anterior pressure on the humerus with external rotation

Anterior glenohumeral instability

Relocation test Posterior force on humerus while externally rotating the arm

Anterior glenohumeral instability

Sulcus sign Pulling downward on elbow or wrist Inferior glenohumeral instability Yergason test Elbow flexed to 90 degrees with forearm

pronated Biceps tendon instability or tendonitis

Speed's maneuver

Elbow flexed 20 to 30 degrees and forearm supinated

Biceps tendon instability or tendonitis

Clunk sign Rotation of loaded shoulder from extension to forward flexion

Labral disorder

NEER'S TEST

Neer's impingement sign is elicited when the patient's rotator cuff tendons are pinched under the coracoacromial arch. The test4 is performed by placing the arm in forced flexion with the arm fully pronated (Figure 5). The scapula should be stabilized during the maneuver to prevent scapulothoracic motion. Pain with this maneuver is a sign of subacromial impingement.

FIGURE 5.

Neer's test for impingement of the rotator cuff tendons under the coracoacromial arch. The arm is fully pronated and placed in forced flexion.

HAWKINS' TEST

The Hawkins' test is another commonly performed assessment of impingement.5 It is performed by elevating the patient's arm forward to 90 degrees while forcibly internally rotating the shoulder (Figure 6). Pain with this maneuver suggests subacromial impingement or rotator cuff tendonitis. One study6 found Hawkins' test more sensitive for impingement than Neer's test.

FIGURE 6.

Hawkins' test for subacromial impingement or rotator cuff tendonitis. The arm is forward elevated to 90 degrees, then forcibly internally rotated.

DROP-ARM TEST

A possible rotator cuff tear can be evaluated with the drop-arm test. This test is performed by passively abducting the patient's shoulder, then observing as the patient slowly lowers the arm to the waist. Often, the arm will drop to the side if the patient has a rotator cuff tear or supraspinatus dysfunction. The patient may be able to lower the arm slowly to 90 degrees (because this is a function mostly of the deltoid muscle) but will be unable to continue the maneuver as far as the waist.

CROSS-ARM TEST

Patients with acromioclavicular joint dysfunction often have shoulder pain that is mistaken for impingement syndrome. The cross-arm test isolates the acromioclavicular joint. The patient raises the affected arm to 90 degrees. Active adduction of the arm forces the acromion into the distal end of the clavicle (Figure 7). Pain in the area of the acromioclavicular joint suggests a disorder in this region.

FIGURE 7.

Cross-arm test for acromioclavicular joint disorder. The patient elevates the affected arm to 90 degrees, then actively adducts it.

Instability Testing

The tests described in this section are useful in evaluating for glenohumeral joint stability. Because the shoulder is normally the most unstable joint in the body, it can demonstrate significant glenohumeral translation (motion). Again, the uninvolved extremity should be examined for comparison with the affected side.7,8

APPREHENSION TEST

The anterior apprehension test is performed with the patient supine or seated and the shoulder in a neutral position at 90 degrees of abduction. The examiner applies slight anterior pressure to the humerus (too much force can dislocate the humerus) and externally rotates the arm (Figure 8). Pain or apprehension about the feeling of impending subluxation or dislocation indicates anterior glenohumeral instability.

FIGURE 8.

Apprehension test for anterior instability. The patient's arm is abducted to 90 degrees while the examiner externally rotates the arm and applies anterior pressure to the humerus.

RELOCATION TEST

The relocation test is performed immediately after a positive result on the anterior apprehension test. With the patient supine, the examiner applies posterior force on the proximal humerus while externally rotating the patient's arm. A decrease in pain or apprehension suggests anterior glenohumeral instability.

YERGASON TEST

Patients with rotator cuff tendonitis frequently have concomitant inflammation of the biceps tendon. The Yergason test is used to evaluate the biceps tendon.9 In this test, the patient's elbow is flexed to 90 degrees with the thumb up. The examiner grasps the wrist, resisting attempts by the patient to actively supinate the arm and flex the elbow (Figure 9). Pain with this maneuver indicates biceps tendonitis.

FIGURE 9.

Yergason test for biceps tendon instability or tendonitis. The patient's elbow is flexed to 90 degrees, and the examiner resists the patient's active attempts to supinate the arm and flex the elbow.

SPEED'S MANEUVER

Speed's maneuver is used to examine the proximal tendon of the long head of the biceps. The patient's elbow is flexed 20 to 30 degrees with the forearm in supination and the arm in about 60 degrees of flexion. The examiner resists forward flexion of the arm while palpating the patient's biceps tendon over the anterior aspect of the shoulder.

SULCUS SIGN

With the patient's arm in a neutral position, the examiner pulls downward on the elbow or wrist while observing the shoulder area for a sulcus or depression lateral or inferior to the acromion. The presence of a depression indicates inferior translation of the humerus and suggests inferior glenohumeral instability (Figure 10). The examiner should remember that many asymptomatic patients, especially adolescents, normally have some degree of instability.

FIGURE 10.

Sulcus test for glenohumeral instability. Downward traction is applied to the humerus, and the examiner watches for a depression lateral or inferior to the acromion.

POSTERIOR APPREHENSION AND INSTABILITY

Posterior instability of the shoulder can be assessed by using a simple test.11 With the patient supine or sitting, the examiner pushes posteriorly on the humeral head with the patient's arm in 90 degrees of abduction and the elbow in 90 degrees of flexion.

CLUNK SIGN

Glenoid labral tears are assessed with the patient supine. The patient's arm is rotated and loaded (force applied) from extension through to forward flexion. A clunk sound or clicking sensation can indicate a labral tear even without instability.12

Cervical Disc Disease

No physical examination in a patient with shoulder pain is complete without excluding cervical spine disease. Referred or radicular pain from disc disease should be considered in patients who have shoulder pain that does not respond to conservative treatment. The patient should be questioned about neck pain and previous neck injury, and the examiner should note whether pain worsens with turning of the neck, which suggests disc disease. Pain that originates from the neck or radiates past the elbow is often associated with a neck disorder.

Plain film is a useful screening tool for degenerative cervical disc disease. Further work-up and imaging studies depend on the differential diagnosis and the treatment plan.

SPURLING'S TEST

In a patient with neck pain or pain that radiates below the elbow, a useful maneuver to further evaluate the cervical spine is Spurling's test. The patient's cervical spine is placed in extension and the head rotated toward the affected shoulder. An axial load is then placed on the spine (Figure 11). Reproduction of the patient's shoulder or arm pain indicates possible cervical nerve root compression and warrants further evaluation of the bony and soft tissue structures of the cervical spine.

FIGURE 11.

Spurling's test for cervical root disorder. The neck is extended and rotated toward the affected shoulder while an axial load is placed on the spine.

The Painful Shoulder: Part II. Acute and Chronic Disorders

Fractures of the humerus, scapula and clavicle usually result from a direct blow or a fall onto an outstretched hand. Most can be treated by immobilization. Dislocation of the humerus, strain or sprain of the acromioclavicular and sternoclavicular joints, and rotator cuff injury often can be managed conservatively. Recurrence is a problem with humerus dislocation, and surgical management may be indicated if conservative treatment fails. Rotator cuff tears are often hard to diagnose because of muscle atrophy that impairs the patient's ability to perform diagnostic maneuvers. Chronic shoulder problems usually fall into one of several categories, which include impingement syndrome, frozen shoulder and biceps tendonitis. Other causes of chronic shoulder pain are labral injury, osteoarthritis of the glenohumeral or acromioclavicular joint and, rarely, osteolysis of the distal clavicle.

Shoulder pain is a common complaint in family practice. Knowledge of the acute and chronic disorders that commonly cause shoulder pain is important because many of them can be managed without referral to a subspecialist.1 This article reviews common causes of shoulder pain and discusses imaging, treatment and indications for referral.

Clavicular Fractures

Clavicular fractures are common, accounting for one of every 20 fractures.2 Most occur in the middle one third of the clavicle. Patients with fracture of the proximal or medial clavicle often have concomitant posterior dislocation of the sternoclavicular joint. Clavicular fractures usually occur during a fall onto an outstretched hand, although some result from a blow to the shoulder. Because the clavicle is directly beneath the skin, these fractures are relatively easy to diagnose: palpation will reveal point tenderness or an obvious deformity. A complete neurovascular examination of the upper extremities should be performed to identify any associated brachial plexus or vascular injuries.

Verification of clinical findings with radiographs is important, particularly to determine whether the patient has a displaced fracture of the proximal or distal clavicle, which may require referral for orthopedic care. A standard anteroposterior (AP) view and an AP view taken with the x-ray beam tilted 45 degrees (cephalic tilt view) are usually adequate. In a patient with substantial trauma, a chest film should be obtained to exclude a concomitant pneumothorax or rib injuries.

Treatment of most clavicular fractures is conservative and consists of a figure-of-eight strap or sling worn for two to four weeks, primarily for comfort. A follow-up radiograph can be obtained four to six weeks after the injury to ensure adequate positioning and healing.

Displaced distal clavicular fractures may result in disruption of the stabilizing ligaments of the acromioclavicular joint. Fractures of this type are more difficult to immobilize properly, and patients with this problem should generally be referred to an orthopedist for further evaluation.

Proximal Humeral Fractures

Humeral fractures are most commonly caused by a direct blow or a fall onto an outstretched hand. Physical examination frequently reveals crepitus at the fracture site. Ecchymosis often occurs within 24 to 48 hours of the injury.

AP and lateral radiographs of the humerus will usually show the fracture. An axillary view should be included if the patient is able to perform the necessary maneuvers (Figure 1). This view is most appropriate for diagnosing dislocations or subtle scapular fractures, particularly those of the coracoid process.3 Because the patient must be able to abduct the arm sufficiently, an axillary view can be difficult to obtain and interpret. The Y view (scapular lateral view) is useful if the patient is unable to abduct the arm (Figure 2).

FIGURE 1.

Radiographs of the shoulder. (Left) True anteroposterior view. (Right) Axillary lateral view.

FIGURE 2.

Y view showing the scapula laterally. The humeral head normally overlies the glenoid cavity.

Fractures of the greater tuberosity may be best visualized with an axillary or a Y view. Additional AP views with the humerus in internal and external rotation are sometimes necessary.

The treatment of stable proximal humeral fractures (those displaced less than 1 cm) consists of a shoulder immobilizer to prevent external rotation and abduction. Referral for surgical treatment may be required for complex fractures (three- and four-part proximal humeral fractures), those involving the anatomic neck, fractures displaced more than 1 cm or those associated with neurovascular injury.4 Follow-up radiographs should be obtained early in treatment to ensure that the fracture fragment has not displaced.

Scapular Fractures

Scapular fractures, which are uncommon,5 result from a direct blow to the scapular area or from extremely high-force impact elsewhere to the thorax. The patient usually has tenderness at the fracture site, and arm abduction is painful. The neck and scapular body are most commonly involved.

Most scapular fractures can be adequately seen with AP and axillary or lateral views of the shoulder. If other injuries are suspected or if the patient was involved in a high-speed or high-force trauma, a chest film and trauma series of the humerus on the affected side should be considered.

Treatment usually consists of a sling for comfort. Range-of-motion exercises are begun as soon as acute pain resolves, usually within two weeks. Early mobilization is important to avoid loss of range of motion, possibly leading to frozen shoulder. Orthopedic referral is indicated for patients with fractures that are unstable or that involve the articular site.

Glenohumeral Dislocation

The glenohumeral joint is normally bathed in a small amount (less than 1 mL) of free synovial fluid. Under normal conditions, the intraarticular pressure is negative, which creates a relative vacuum that resists bony translation.6

The humeral head can dislocate anteriorly, posteriorly or inferiorly in relation to the glenoid fossa. Most shoulder dislocations are anterior. Patients usually hold the affected arm in external rotation and abduction. The humeral head usually is palpable anteriorly, and the diagnosis is often confirmed by locating a dimple in the skin beneath the acromion.

Posterior dislocation is uncommon, and diagnosis is often delayed. Typically, the patient presents with the arm held close to the body in abduction and internal rotation. Usually, external rotation (active and passive) and forward elevation are extremely limited.

Younger athletes and older adults can have a fractured proximal clavicle rather than a dislocation with a similar mechanism of injury.

The diagnosis of glenohumeral dislocation is confirmed with at least two radiographic views of the affected shoulder. A true AP view, with the x-ray beam perpendicular to the plane of

the scapula, usually reveals an anterior dislocation but can miss a posterior dislocation. An axillary or a Y view provides a more accurate picture of the anteroposterior position of the humeral head relative to the glenoid fossa3 (Figure 3). If the diagnosis is still unclear after plain films have been obtained, a computed tomographic (CT) scan should be considered. Care should be taken to look for an avulsion fracture of the glenoid (Bankart lesion). This injury usually requires surgical repair (Figure 4).

FIGURE 3.

Anteroposterior views of the shoulder, showing anterior dislocation (left) and normal alignment after reduction (right).

FIGURE 4.

Computed tomographic arthrogram showing a Bankart lesion with a spur extending off the inferior glenoid. The anteroinferior labrum is absent.

A patient with recurrent anterior shoulder dislocation often has subtle clinical findings. Tenderness may be noted over the posterior aspect of the shoulder. The anterior apprehension test usually causes more pain than apprehension. A Hill-Sachs lesion (a bony

defect in the posterolateral portion of the humeral head) occurs in more than 50 percent of patients with a primary dislocation.7 This lesion is associated with an increased risk of recurrent dislocation (Table 1).

TABLE 1 Complications of Anterior Shoulder Dislocation

Complication Incidence Recurrent dislocation Decreased occurrence with age Bony injury Hill-Sachs lesion* in > 50% of patients with primary dislocation Rotator cuff tear 50% in patients < age 40; 80% in those > 60 Vascular injury Increased occurrence with advanced age Neurologic injury Most common in axillary nerve Arthropathy 20% of patients 10 years after dislocation

*Bony defect in posterolateral humeral head.

Information from Hovelius L, Augustini BG, Fredin H, Johansson O, Norlin R, Thorling J. Primary anterior dislocation of the shoulder in young patients: a ten-year prospective study. J Bone Joint Surg [Am] 1996;78:167784.

Shoulder dislocation is treated with relocation of the humerus (using the method with which the clinician is most familiar) and immobilization, to permit capsular healing. Mobilization of the shoulder and the elbow can usually be resumed within seven to 10 days following injury. Early range-of-motion exercises are important, particularly in older patients, to prevent complications such as frozen shoulder.

A more aggressive rehabilitation program with a shorter course of immobilization has been advocated for elite athletes.8,9 Reported recurrence rates of anterior dislocations, particularly in younger athletes who throw overhead, are as high as 90 percent,10,11 although a recent prospective Swedish study demonstrated lower rates of recurrence.7

The classic treatment of recurrent shoulder dislocations has been open surgery and a Bankart repair (surgical repair of a detachment of the labrum to the glenoid). This approach has a success rate as high as 95 percent.12 In a recent study of young athletes, arthroscopic Bankart repair was compared with three weeks of immobilization for the treatment of an initial anterior shoulder dislocation. The group treated surgically had fewer episodes of recurrent instability than the group managed with immobilization.9 Based on these results, early surgery may have a role in the treatment of high-performance athletes with anterior glenohumeral dislocation.

Acromioclavicular Joint Sprain and Separation

A common injury among athletes and active patients is acromioclavicular (AC) sprain, also referred to as shoulder separation. The current classification system recognizes six grades of AC ligamentous injuries (Table 2).13 A direct blow to the superior aspect of the shoulder

or a lateral blow to the deltoid area often produces this injury. Occasionally, an AC sprain results from falling onto an outstretched hand.

TABLE 2 Classification of Acromioclavicular (AC) Joint Injuries

Ligaments or joint Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 Grade 6 Acromioclavicular ligaments

Sprained Disrupted Disrupted Disrupted Disrupted Disrupted

Acromioclavicular joint

Intact Disrupted or slight vertical separation

Disrupted Disrupted Separated Ruptured

Coracoclavicular ligaments

Intact Sprained Disrupted or slight vertical separation

Disrupted Disrupted Disrupted

Adapted with permission from Rockwood CA Jr. In: Rockwood CA Jr, Green DP, Bucholz RW. Rockwood and Green's Fractures in adults. 4th ed. Philadelphia, Pa.: Lippincott-Raven, 1996;1341407.

On examination, the patient has well-localized swelling and tenderness over the AC joint. When an AC joint injury is suspected, the patient should be examined in the sitting position because the weight of the arm in the standing position stresses the AC joint and may exaggerate an existing problem. A palpable stepped deformity between the acromion and the clavicle indicates a more severe injury, possibly a complete dislocation. An AP view of the shoulder usually confirms the diagnosis. An axillary view should be obtained if a grade 4 to grade 6 injury is suspected.

Most patients with grades 1 and 2 injuries can be treated without surgery. In some patients, however, a grade 2 lesion can be difficult to differentiate from a grade 3 injury on routine radiographs if the patient supports the injured side. Patients with grade 3 and higher injuries should generally be referred to an orthopedist for possible operative repair. Grades 2 and 3 injuries are often associated with chronic AC joint pain.

Sternoclavicular Joint Sprain and Separation

Anterior sternoclavicular (SC) joint separation occurs when the medial end of the clavicle is displaced anteriorly or anterosuperiorly with respect to the anterior border of the sternum. This injury is most commonly the result of a motor vehicle crash.14 The patient with an SC joint injury will complain of pain, particularly with shoulder adduction. Localized tenderness and deformity are often noted. The head may be tilted toward the side of the dislocation. When the patient is supine, the discomfort is often exacerbated, and the patient cannot place the affected shoulder flat on the examining table. A posterior dislocation can be life-threatening because of compression of the trachea and great vessels of the neck.

The SC joint and proximal physis of the clavicle can be difficult to see on plain films. A modified radiographic view, such as a 40-degree cephalic tilt view, is often helpful. A CT scan

can provide more detail about the extent of injury. Mild SC sprains are usually treated conservatively with a sling or figure-of-eight appliance and progressive range-of-motion exercise. Acute SC dislocations can be managed with closed reduction by experienced physicians, but surgical reduction for definitive management is often required.

Rotator Cuff Tear

Tears of the rotator cuff are most common in persons older than 40 years.15 In younger patients, these injuries typically result from trauma. In middle-aged or older patients, a more common presentation is chronic impingement syndrome, often resulting in rupture of the cuff. When a rotator cuff ruptures, the resulting muscular atrophy often limits the patient's ability to perform the necessary diagnostic maneuvers. In these patients, a rotator cuff tear can be difficult to diagnose clinically. An AP view of the glenohumeral joint may show calcific tendonitis of the cuff and superior migration of the humeral head, which should prompt further imaging studies if the clinician suspects a tear15,16 (Table 3).

TABLE 3 Imaging Studies of the Shoulder

Imaging modality Advantages Disadvantages MRI 95% sensitivity and specificity in detecting

complete rotator cuff tears, cuff degeneration, chronic tendonitis and partial cuff tears

Often identifies an apparent abnormality in an asymptomatic patient

No ionizing radiation Arthrography Good at identifying complete rotator cuff

tear or adhesive capsulitis (frozen shoulder) Invasive Relatively poor at diagnosing a partial rotator cuff tear

Ultrasonography Accurately diagnoses complete rotator cuff tears

Less useful in identifying partial cuff tears Operator-dependent interpretation

MRI arthrography

Reliably identifies full-thickness rotator cuff tears and labral tears

Invasive

CT scanning May be useful in diagnosis of subtle dislocation

Ionizing radiation

MRI = magnetic resonance imaging; CT = computed tomographic.

Treatment consists of surgical repair in younger and selected older patients or rehabilitation in patients who are not good candidates for surgery. Early identification of a rotator cuff tear is important so that consultation for possible surgical repair can be considered. Repair within three weeks of injury is recommended to avoid tendon retraction, reinjury, tendon degeneration and muscle atrophy.

Impingement Syndrome

The rotator cuff occupies the space between the coracoacromial arch and the humerus. With abduction of the arm, the tendons of the rotator cuff can be impinged between the bony structures of the arch and the humerus. The impingement syndrome was described by Neer17,18 as a series of pathologic changes in the supraspinatus tendon: stage I causes hemorrhage and edema; stage II, tendonitis and fibrosis; and stage III, tendon degeneration of the rotator cuff and biceps, bony changes and tendon rupture.

Pain related to impingement usually occurs over the anterolateral aspect of the shoulder, often with some radiation to, but not usually beyond, the elbow. Typically, the pain is aggravated by overhead activity and is worse at night. Patients often report a clicking or popping sensation in the affected shoulder. In young throwing athletes with these symptoms, however, the examiner should be concerned about the possibility of a labral disorder. Biceps tendonitis frequently occurs in the later stages of impingement, and rehabilitation can help correct this problem.19

The examiner should distinguish between primary and secondary impingement. Initial treatment of both conditions is conservative, but when conservative treatment fails, the surgical approach to the two problems differs markedly. Symptoms in older patients usually reflect chronic overuse and degeneration of the supraspinatus tendon. This process is referred to as primary impingement. For instance, a 65-year-old patient with anterior shoulder pain probably has primary outlet impingement. In contrast, a 17-year-old baseball pitcher is more likely to have secondary impingement, with an underlying problem of instability. This patient will often complain of arm heaviness and numbness (dead arm syndrome) rather than shoulder pain.20

Therefore, the primary diagnosis in younger throwing athletes is typically subtle glenohumeral instability with secondary impingement and subacromial bursitis noted on examination. Weakness in the scapular stabilizers can play an important role in the development of shoulder problems, particularly in athletes.21 Repeated stresses from overhead motions like throwing can lead to fatigue of the muscles that stabilize the humeral head and prevent anterior subluxation. Secondary impingement, therefore, can occur when the fatigue and dysfunction of the rotator cuff cause the humeral head to migrate superiorly within the glenohumeral joint, impinging the rotator cuff tendon under the coracoacromial arch.

Other causes of impingement include a curved or hooked acromion, AC spurring and a thickened coracoacromial ligament.22 Radiographs should be considered if a patient shows no improvement after two to three months of conservative therapy for presumed impingement syndrome (Table 4).23 Degenerative changes at the AC joint, sclerosis, osteophyte formation at the inferior aspect of the acromion and sclerosis or cyst formation at the site of supraspinatus tendon insertion into the greater tuberosity should increase the clinician's suspicion of impingement and chronic rotator cuff tears. In some cases, magnetic resonance imaging (MRI) or other imaging studies (Table 3) may be necessary. T2-weighted MRI has a reported accuracy of 84 to 100 percent in the diagnosis of rotator cuff tears.15,16

TABLE 4 Suggested Radiographs for Anterior Shoulder Pain

Radiograph Abnormality best visualized AP view of glenohumeral joint Degenerative glenohumeral changes AC joint AC degenerative changes

AC joint separation Distal clavicle fracture

Axillary lateral view of shoulder Glenohumeral dislocation Bony Bankart lesion*

Supraspinatus outlet (arch) Abnormality of acromion process Degenerative changes of anterior acromion

AP = anteroposterior; AC = acromioclavicular.

*Avulsion fracture of the glenoid.

Adapted with permission from Lyons PM, Orwin JF. Rotator cuff tendinopathy and subacromial impingement syndrome. Med Sci Sports Exerc 1998;30(4 suppl):S127.

Initial treatment of most patients with impingement syndrome (primary and secondary) is conservative, especially in the acute phase of pain: rest, nonsteroidal anti-inflammatory drugs (NSAIDs), icing and avoiding aggravating activities. It may be necessary to modify the patient's work activities, particularly overhead lifting. After most of the pain has resolved, a rotator cuff strengthening program should be instituted. In some patients, particularly athletes with secondary impingement, scapular rotator cuff strengthening also should be incorporated into the physical therapy program. Athletes with secondary impingement and underlying instability who fail to show improvement with conservative therapy should be referred for consideration of a stabilization procedure. In contrast, an older patient with primary impingement would probably undergo open or arthroscopic subacromial decompression.

A corticosteroid injection can be therapeutic and diagnostic in patients with impingement syndrome. If the diagnosis of impingement is uncertain, lidocaine (Xylocaine) and/or bupivacaine (Marcaine) can be injected into the subacromial space. After the drug has dispersed for several minutes, impingement tests can be repeated. A decrease in pain increases the certainty that impingement is the primary process. Corticosteroids are often combined with anesthetics in this procedure. A recent randomized, double-blind study24 noted significant short-term relief of subacromial impingement symptoms with corticosteroid injections.

Frozen Shoulder

Adhesive capsulitis, or frozen shoulder, results from thickening and contraction of the capsule around the glenohumeral joint and causes loss of motion and pain. Frozen shoulder classically consists of shoulder pain that is slow in onset and presents without any radiographic abnormalities. Usually, the discomfort is localized near the deltoid insertion,

the patient is unable to sleep on the affected side and glenohumeral elevation and external rotation are restricted.

Frozen shoulder most often occurs as a result of immobility following a shoulder injury. An autoimmune cause of frozen shoulder has been proposed.25,26 The diagnosis is usually made clinically, and physicians should always be concerned about a possible underlying rotator cuff tear. Radiographs often appear normal, although osteopenia of the humeral head may be noted as a result of disuse. Arthrography demonstrates generalized constriction of the joint capsule, with loss of the normal axillary and subscapularis spaces. The capsule can be dilated during arthrography, converting the procedure from a diagnostic to a therapeutic one.

A carefully designed treatment plan for patients with frozen shoulder may include physical therapy, pain medication such as NSAIDs and, occasionally, intra-articular corticosteroid injection. Surgical referral may be indicated after conservative treatment has failed, although the exact timing of surgery should be decided on an individual basis.

Biceps Tendonitis

Biceps tendonitis results from inflammation of the sheath around the long head of the biceps and is usually manifested by discrete pain and tenderness in the area of the bicipital groove, often occurring concomitantly with impingement syndrome or rotator cuff tear. Management is usually conservative; rest, icing, NSAIDs and corticosteroid injections may all be helpful. When conservative management fails, surgical transfer of the tendon may be necessary.

Labral Injury

The SLAP lesion (superior labrum anterior and posterior) and other glenoid labral tears are common in throwing athletes who present with a painful shoulder that clicks or pops with motion. Patients often have a positive clunk test,27 especially in the overhead position. They may have tenderness to deep palpation over the anterior glenohumeral joint and signs of laxity or instability. Plain films are often normal, and MRI arthrography may be needed to view the torn labrum (Table 3). For patients who do not respond to rest, NSAIDs and physical therapy, arthroscopic or open surgical repair may be indicated.

Glenohumeral Arthritis

Arthritis of the glenohumeral joint generally causes pain with activity, loss of passive motion and stiffness. Some patients may complain of nighttime pain. Causes of arthritis include previous trauma, rheumatoid arthritis, rotator cuff tear and Lyme disease. Multiple joint involvement is suggestive of rheumatoid arthritis.

An AP view of the glenohumeral joint will usually reveal degenerative changes and loss of joint space (Table 2). Treatment is initially conservative, using heat and ice, NSAIDs, range-of-motion exercises and corticosteroid injections. Patients for whom conservative therapy fails can be referred for further evaluation and treatment.

Osteolysis of the Distal Clavicle

Atraumatic osteolysis of the distal clavicle is an unusual injury that occurs most often in weight lifters.28 Although its cause remains obscure, the problem most likely begins as a stress fracture. Subsequent bone resorption causes cystic and erosive changes, and bone remodeling cannot occur because of the continual stress imposed on the joint. Patients typically have dull pain over the AC joint, which is often worst at the beginning of an exercise period. Any movement requiring abduction of the arm more than 90 degrees is painful.

Plain films of the AC joint and clavicle usually confirm the diagnosis. Key findings include osteopenia and lucency in the distal clavicle (Figure 5). Treatment consists of discontinuing load-bearing activity. Conservative management should be used for as long as the patient will comply. Consideration for resection of the distal clavicle should be individualized according to each patient's functional demands and symptoms.

FIGURE 5.

Osteopenia and lucency in a patient with osteolysis of the distal clavicle.