What are the Symptoms of Osteolysis of the Acromioclavicular Joint?
In both atraumatic and traumatic osteolysis, the patient usually reports a dull ache that is localized over the AC joint. It may radiate to the anterior deltoid or trapezius. With posttraumatic osteolysis, the patient will sometimes relate the onset of pain to a direct blow to the shoulder. Since the traumatic episode may have occurred between 4 weeks to several years prior to the onset of symptoms, specific questions about previous trauma should be asked. These patients may or may not be involved in repetitive physical activity with he affected shoulder.
With atraumatic osteolysis, the patient has an insidious onset of pain in the region of the AC joint. These patients are usually weight lifters or heavy laborers who do not recall a specific injury that may have precipitated their pain. Weight lifters may have more pain while performing bench presses, push-ups, and dips. Patients may note pain at night, with nocturnal awakening when rolling onto the affected shoulder. There may be associated symptoms of popping, catching or grinding. Activities of daily living may become painful as the patient’s symptoms progress.
How do I Know I Have Osteolysis of the Acromioclavicular Joint
Inspection of the affected shoulder may reveal joint prominence or asymmetry. Palpation over the AC joint will reveal tenderness. Provocative tests, such as reaching across to touch the opposite shoulder or placing the hand behind the back, may cause localized pain. Active motion of the shoulder may cause crepitus which must be differentiated from subacromial crepitus.
Motion is rarely restricted, although in long-standing cases mild restrictions of internal rotation and / or cross-body adduction may develop. Restricted motion should be documented by comparing both shoulder. More significant restricted motion in the painful shoulder suggests adhesive capsulitis or glenohumeral arthritis.
The most reliable physical examination test is the cross-body adduction test, in which the arm on the affected side is elevated to 90 degrees and the examiner grabs the elbow and adducts the arm across the body. This will cause pain at the AC joint if there is true pathology in the AC joint. This test may cause pain in posteriorly in patients with subacromial impingement if they have posterior capsular tightness.
In patients with isolated AC joint pathology, an injection of 1ml of 1% lidocaine directly into the AC joint will experience pain relief while patients with subacromial pain or other pathology will still have pain on provocative testing.