Shoulder Pain Management
Painful osteoarthritis of the acromioclavicular (AC) joint is common and is often overlooked by physicians because the resulting shoulder pain may not be well localized to the AC joint. Typically, AC joint pain is described as a dull ache involving the deltoid area that is exacerbated by motion.1 Although most planes of motion will cause pain, horizontal cross-body adduction (such as occurs when reaching over the front of the body) will most consistently cause pain. Patients may complain of the inability to sleep on the affected side. This complaint is likely due to irritation of the underlying subacromial bursa by inferior-projecting osteophytes from the AC joint.2
- Key Observations
- Shoulder pain is a common symptom of osteoarthritis of the acromioclavicular joint
- Shoulder movement, especially in a horizontal direction, causes pain
- Common complaints include inability to sleep on the affected side
Even to experienced physicians, the clinical presentation of AC osteoarthritis can be deceiving. Examination of the cervical spine should be performed to rule out abnormalities, including radiculopathy and degenerative joint disease that may cause referred pain in the shoulder. During the examination, the shoulder should be inspected and palpated, and the muscle strength as well as the range of motion assessed. Range of motion should be performed actively and passively and compared with that of the asymptomatic side.3 Active and passive range of motion testing may reveal joint prominence or asymmetry.
- Clinical Clues
- Localized pain and swelling over the acromioclavicular joint
- Pain on cross-body adduction of the arm
- Pain on strenuous physical activity
- X-rays show degenerative changes in acromioclavicular joint
In patients with AC osteoarthritis, range of motion tends to vary greatly, as there may be coexisting rotator cuff or capsule pathology. In addition, if AC osteoarthritis has been symptomatic for a prolonged period of time, adhesive capsulitis may result. Overall, most patients should have nearly full passive range of motion accompanied by pain. It is common for pain to be present with larger arc motions (120-180 degrees versus 60-120 degrees). This typical painful arc should be distinguished from rotator cuff impingement.1
Pain may be reliably reproduced with passive horizontal cross-body adduction at 90 degrees of forward flexion. To perform the test, passively forward flex the arm to 90 degrees and then horizontally adduct the arm as far as possible. Localized pain over the AC joint is fairly specific for AC joint pathology and is considered diagnostic (Fig. 1).4 Direct manual pressure on the superior surface of the AC joint should also reproduce symptoms. A significant difference should be noted between the affected and unaffected sides.
Figure 1: AC compression test. This is a cross body adduction maneuver that compresses the AC joint. A positive test produces pain on the top of the shoulder.5
An active compression test will help exclude labral pathology as a source of pain (Fig. 2). Have the patient forward flex the arm to 90 degrees with the elbow fully extended and adduct the arm 15 degrees medial to the midline of the body with the thumb pointed downward. Then push the arm down while the patient resists. In the second part of the text, the test is repeated with the arm in the same position, but the patient fully supinates with the palm facing the ceiling. If pain is produced in the first position and reduced or absent in the second, a superior labral injury is more likely than AC joint pathology.4
Figure 2: Active compression test (O'Brien test). This test is performed by having the patient place his or her arm forward flexed to 90 degrees with 10 degrees of horizontal adduction and internal rotation (thumb down). A positive test is signified by pain on top of the shoulder when the arm is pushed in a downward direction, which is lessened when the test is repeated with the arm in external rotation (thumb up).5
- Confounding Sources of Pain
- Full-thickness rotator cuff tears
- Septic shoulder
- Cervical spine disorders
- Referred pain from cardiac, pulmonary or visceral sources
- Soft tissue tumors
Patients with AC joint arthritis will have a clinical course similar to other joints with osteoarthritis. The condition gradually becomes more severe. Symptoms are usually intermittent, take decades to become very severe and depend on activity. Surgery can produce good results, but should be reserved for patients who fail conservative therapy for a prolonged period of time and who have significant structural issues of the joint.
Osteoarthritis of the AC joint is a common yet overlooked cause of shoulder pain. Although treatment options are few, proper diagnosis and management may prevent further complications, including inappropriate management, worsening limitations in range of motion, impaired function, and unnecessary procedures and treatments for other diagnoses.
- Know When to Refer
- Patient not responding to 3 to 6 months of conservative treatment
- Glenohumeral instability
- Suspected full-thickness rotator cuff tears
- Suspected rheumatoid arthritis
- Symptomatic os acromiale
- Ganglion cyst of the shoulder
- Recalcitrant adhesive capsulitis
The ICD9 code for osteoarthritis of the AC joint is 716.91 (Unspecified arthropathy involving shoulder region).
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Content in this section is adapted and/or repurposed with permission from:
Lotke, PA, Abboud, JA, Ende, J. Lippincott’s Primary Care Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:section 8.
Authors: Abboud, JA, Ricchetti, ET, Tjoumakaris, FP, Yagnik, GP.
Lippincott Williams & Wilkins <http://lww.com>
- Shaffer BS. “Painful Conditions of the Acromioclavicular Joint.” J Am Acad Orthop Surg. 1998;7:176-188.
- Buttaci CJ, Stitik TP, Yonclas PP, et al. “Osteoarthritis of the Acromioclavicular Joint: a Review of Anatomy, Biomechanics, Diagnosis, and Treatment.” Am J Phys Med Rehabil. 2004;83:791-797.
- Arroyo JS, Flatow EL. “Management of Rotator Cuff Disease: Intact and Repairable Cuff.” Iannotti JP, Williams GR, Eds. Disorders of the Shoulder: Diagnosis and Management. Philadelphia: Lippincott Williams & Wilkins. 1999;31-56.
- Tokish JM. “Clinical Examination of the Overhead Athlete: The Differential Directed Approach.” Krishnan SG, Hawkins RJ, Warren RF, Eds. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins. 2004;23-49.
- Tokish JM. “Clinical Examination of the Overhead Athlete: The Differential Directed Approach.” Krishnan SG, Hawkins RJ, Warren RF, Eds. The Shoulder and the Overhead Athlete. Philadelphia: Lippincott Williams & Wilkins. 2004;33.