What are the treatment guidelines for a patient presenting with shoulder AC joint pain, assuming no severe trauma or underlying condition?

Treatment Guidelines for AC Joint Pain

For AC joint pain without severe trauma, initial management should consist of conservative treatment including activity modification, NSAIDs, and physical therapy for at least 6 months before considering surgical intervention. 1

Initial Diagnostic Workup

Obtain standard shoulder radiographs as the first-line imaging study, which should include at minimum three views: anteroposterior (AP) views in internal and external rotation plus an axillary or scapula-Y view. 2 These radiographs effectively demonstrate AC joint pathology, fractures, and shoulder alignment abnormalities. 3

Perform a diagnostic local anesthetic injection into the AC joint to confirm the AC joint as the pain source, as this is essential for proper diagnosis of AC joint pathology. 1 If the injection provides significant pain relief, this confirms AC joint pathology as the primary pain generator.

Conservative Management (First-Line Treatment)

Pharmacological Management

• Prescribe oral NSAIDs as first-line pharmacological therapy to reduce pain and diminish inflammation in the joint. 4
• Consider oral vitamin C and vitamin D supplementation to help slow cartilage degeneration. 4
• Administer intra-articular corticosteroid injections if diagnostic local anesthetic injection provided relief, though evidence suggests these provide only short-term pain relief and do not alter disease progression. 1

Activity Modification

Emphasize activity modification as a primary treatment strategy, particularly avoiding overhead activities and movements that provoke AC joint pain. 1, 5 This is especially important for weight-training athletes, as AC joint osteolysis is increasingly prevalent in this population. 5

Physical Therapy Considerations

Physical therapy plays a limited role in AC joint pathology, as therapeutic exercise and range of motion have minimal impact on AC joint-specific pain. 1 However, rotator cuff strengthening exercises may help protect the glenohumeral joint and improve overall shoulder function. 4

Duration of Conservative Treatment

Continue conservative management for a minimum of 6 months before considering surgical intervention. 1 Most AC joint conditions can be successfully managed conservatively with this approach. 6

Surgical Intervention

Consider distal clavicle resection (open or arthroscopic) only after 6 months of unsuccessful conservative treatment. 1

Surgical Approach Options

• Arthroscopic resection is preferred over open procedures when surgery is indicated, as it offers less compromise of musculotendinous structures, shorter rehabilitation, and quicker return to activity. 6
• Resection of 4-8 mm of bone is typically sufficient for good clinical outcomes, which is less than required for open procedures due to preservation of superior AC ligaments. 6
• The indirect (bursal) approach allows assessment of both the subacromial space and AC joint, which is advantageous since impingement pathology frequently coexists with AC joint changes. 6

Important Clinical Pitfalls

Do not overlook the AC joint when evaluating shoulder pain, as it is commonly neglected despite being a frequent pain source, with clinicians often focusing primarily on rotator cuff pathology, bursitis, and labral tears. 1

Avoid premature surgical intervention, as most AC joint conditions respond to conservative management, and surgery should be reserved for patients who fail conservative treatment or athletes unwilling to modify activities. 6

Be aware that Grade II AC sprains can result in significant weakness (24.3% deficit in horizontal abduction at fast velocity), despite being considered less severe injuries. 7

Recognize that Grade III AC separations treated conservatively show no significant strength deficits, though patients may experience more pain and stiffness compared to surgically treated cases. 7

Advanced Imaging Considerations

Reserve MRI for cases where radiographs are noncontributory but symptoms persist, with MRI without contrast (rating 7/9) or MR arthrography (rating 9/9) being appropriate for suspected soft tissue injuries. 3

CT scanning may be used for better characterization of fracture patterns when radiographs show bony abnormalities requiring further evaluation. 3