Shoulder Pain That Prevents a Painter From Working

A 55-year-old right-handed house painter has had a constant dull ache in his right shoulder for 3 weeks. The pain worsens when he steers his car or elevates his arm, and the inability to raise his arm above his head interferes with his work. The pain radiates to his neck and upper right arm (but not the forearm); at night, it occasionally becomes severe enough to waken him. Neck movement does not make the pain worse, and he has no weakness or numbness in his right arm or hand.

There is no history of acute trauma. He has had intermittent shoulder pain for the past few years that was alleviated by acetaminophen.

The patient has type 2 diabetes and hyperlipidemia. His medications include atorvastatin, metformin, and low-dose aspirin.

What is your presumptive diagnosis at this point?

A.

Statin-induced myositis.

B.

C5-C6 nerve root compression.

C.

Rotator cuff impingement syndrome.

D.

Acromioclavicular joint arthritis.

E.

Diabetic neuropathy.THE CONSULTANT'S CHOICE

This man most likely has rotator cuff impingement syndrome (choice C). Rotator cuff problems make up 60% to 70% of the shoulder problems encountered in the primary care setting. Affected patients are typically older than 40 years.¹

Chronic progressive pain that worsens at night and with elevation of the arm ("painful arc") is a classic presentation of rotator cuff impingement. The pain is usually localized to the superior lateral portion of the shoulder but can radiate to the neck and the arm; however, it does not radiate below the elbow. Patients like this man may be involved in an occupation or sport that requires recurrent overhead activity.

C5-C6 cervical root compression (choice B) might be considered here; however, the pain of nerve root compression usually radiates to the hands and is made worse by neck movement. In addition, numbness and weakness of the arm and hands are usually present. This patient's pain does not radiate to the hands and is not increased by neck movement--nor does he have numbness or muscle weakness.

Statin-induced myositis (choice A) is unlikely because it usually affects more than one muscle group; this man's discomfort is confined to his shoulder.

Diabetic neuropathy (choice E) affects the lower extremities, not the shoulder. Moreover, the pain of diabetic neuropathy is described as a constant burning and is not related to movement.

Acromioclavicular (AC) joint arthritis (choice D) is a possibility. However, it usually causes isolated pain on the superior aspect of the shoulder over the AC joint. It does not cause pain with arm elevation; rather, the arm on the affected side must be crossed over the body until it touches the other shoulder in order to completely reproduce the pain. Furthermore, AC joint pain is usually not nocturnal and it does not radiate.

Which two of the following tests are most likely to yield positive results in this setting?

A. Spurling maneuver.
B. Hawkins test.
C. "Empty can" test.
D. Crossover test.
E. "Drop arm" test.
F. Anterior apprehension test.

THE CONSULTANT'S CHOICE

The rotator cuff is formed by the tendons of 4 muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that come together in the joint capsule to form a musculotendinous collar that surrounds the humeral head. This structure helps stabilize, rotate, and abduct the shoulder. When the arm is abducted 90 degrees, the tendons of the supraspinatus and the superior portion of the infraspinatus become interposed between the greater tuberosity of the humerus and the acromion. Depending on the shape of the acromion, the tendons may become impinged, and chronic degenerative changes, micro-tears, and macro-tears can occur.

Both the Hawkins test (choice B) and the "empty can" test (choice C) can demonstrate impingement and rotator cuff disease. The Hawkins test is a reliable test for impingement of the rotator cuff--especially the supraspinatus contribution to the cuff. To perform it, abduct the symptomatic arm 90 degrees in the frontal plane and then induce internal rotation in an attempt to elicit pain (Figure 1). Because this maneuver can be fairly uncomfortable, perform it gradually and stop when pain develops.

In the "empty can" test (Figure 2), the patient abducts both arms 90 degrees laterally, then adducts them 20 degrees to the frontal plane, with thumbs turned down. The examiner resists further abduction to test strength and watches for signs of pain.

The other tests listed are also important to perform, although their purpose is primarily to rule out other conditions. Complete tears of the rotator cuff are not common and can be diagnosed clinically by the "drop arm" test (choice E). Perform this test by asking the patient to abduct his or her arm 90 degrees and hold it. If the arm drops when you tap it lightly, the result is considered positive. In addition, complete cuff tears cause infraspinatus atrophy and posterior scapular muscle wasting.

The Spurling maneuver (choice A) is helpful in the diagnosis of cervical root compression. It consists of having the patient extend his neck, rotate it, and bend it laterally toward the affected side. This closes the neural foramina; thus, it can reproduce pain that radiates to the hand. Pain in the neck alone does not constitute a positive result.

The crossover--or cross-arm--test (choice D) can help diagnose AC joint arthritis or AC joint separation. Ask the patient to adduct the arm on the affected side across the body, and touch the opposite shoulder with a finger. This test compresses the AC joint and causes discomfort in persons in whom the joint is arthritic. Having the patient resist your efforts to press down on the arm will accentuate the pain.

The anterior apprehension test (choice F) helps identify shoulder subluxation, which is more likely to occur in the setting of rotator cuff impingement. To perform this test, have the patient abduct the arm 90 degrees with the elbow flexed 90 degrees. Then have the patient externally rotate the shoulder while you put pressure on the humeral head to induce subluxation. Significant discomfort and a desire to stop the test indicate subluxation. Crepitus without pain is not significant.

Results of the Hawkins and "empty can" tests are both positive in this patient. Results of the Spurling, "drop arm," anterior apprehension, and crossover tests are all negative, and no evidence of posterior scapular muscle wasting is noted. Thus, the diagnosis of rotator cuff impingement syndrome seems most likely.

Which two of the following would you do now?

A.

Obtain a plain radiograph.

B.

Obtain an MRI scan.

C.

Start treatment with rotator cuff exercises.

D.

Inject the supraspinatus bursa with lidocaine and a corticosteroid.

E.

Refer the patient for an orthopedic consultation.THE CONSULTANT'S CHOICE

Imaging studies (choices A and B) are not indicated here. There has been no direct trauma to the shoulder; thus, a fracture is not likely. The result of the anterior apprehension test is negative; thus, the bone loss in the humeral head and glenoid rim that is associated with recurrent subluxation is also unlikely. MRI is not indicated because neither a complete cuff tear nor subluxation is suspected. (MRI can help detect tears in the labrum [cartilaginous tissue that cushions the humeral head against wear in the scapular glenoid fossa], which are often seen in recurrent subluxation.) An orthopedic consultation (choice E) is not needed at this time. However, if the patient fails to respond to conservative measures, an orthopedic consultation would be warranted.

Rotator cuff exercises (choice C) are the mainstay of treatment. These can be demonstrated by the clinician or by another member of the staff. Some patients do better if a physical therapist teaches the exercises. Rotator cuff exercises can also be downloaded from numerous Web sites (Box).

Injecting the bursa (choice D) is most helpful when a patient has too much discomfort to perform the exercises--as this man seems to. The injection provides sufficient relief to give the patient confidence that he will be able to do the exercises. A posterior, anterior, or lateral injection site may be used. If the humeral head is moved forward (as is common in rotator cuff disease), a posterior approach is much easier (Figure 3). Advise patients to wait about 36 hours after the injection before starting the exercises.

References:

REFERENCE:

1.

Richmond JC, Shahady EJ.

Sports Medicine for Primary Care.

Cambridge, Mass: Blackwell Science; 1996.