What is the recommended treatment for an adult patient with a positive Can test indicating subacromial impingement syndrome or rotator cuff tendinopathy in the right shoulder?

Treatment for Right Shoulder with Positive Can Test

Begin with conservative management consisting of NSAIDs, activity modification, and a structured exercise program focused on eccentric strengthening and stretching, reserving corticosteroid injection for persistent symptoms beyond 6 weeks. 1, 2

Initial Conservative Management (First 6 Weeks)

Start with non-operative treatment as the preferred approach for subacromial pain syndrome. 2

• Analgesics and NSAIDs should be used for acute pain control, though evidence for NSAIDs specifically in rotator cuff pathology is limited 1, 3
• Activity modification to minimize repetitive overhead stresses is essential, particularly for athletes and manual laborers 1
• Ice application can be used, though evidence is weak 3

Exercise Therapy: The Cornerstone of Treatment

Exercise therapy should be specific, low intensity, and high frequency, combining eccentric training with attention to posture and stretching. 2, 4

• Eccentric strengthening exercises are recommended to reduce symptoms, increase strength, and promote tendon healing 1, 4
• Stretching and flexibility work should target the rotator cuff muscles and address any myofascial trigger points 2
• Supervised versus home exercise programs show similar outcomes, so either approach is acceptable based on patient preference and resources 4
• Avoid strict immobilization as this is not recommended 2

Corticosteroid Injection: Timing and Indications

Subacromial corticosteroid injection is indicated for persistent or recurrent symptoms, but should be used judiciously. 2

• Timing: Consider injection after 6 weeks of failed conservative management 2
• Caution: Avoid multiple repeated injections without clear benefit, as corticosteroids may compromise tendon biology and future surgical outcomes if needed 3
• Evidence: While corticosteroid injections can provide short-term relief, they do not change long-term outcomes 1

Diagnostic Imaging: When to Order

Obtain ultrasound imaging after 6 weeks of persistent symptoms to exclude rotator cuff tear. 2

• Ultrasound is the recommended first-line imaging modality to evaluate for rotator cuff pathology 2
• MRI without contrast is equivalent to ultrasound for evaluating bursitis and tendinopathy when local ultrasound expertise is available 1
• The Can test (empty can test) is sensitive but not specific for supraspinatus impingement, similar to Hawkins' (92% sensitive, 25% specific) and Neer's tests (88% sensitive, 33% specific) 1

Additional Modalities with Limited Evidence

The following interventions lack sufficient evidence for routine recommendation:

• Therapeutic ultrasound, ESWT, iontophoresis, and phonophoresis have weak or inconsistent evidence 1
• TENS, massage, and other physical modalities cannot be recommended based on current evidence 3
• Orthotics and braces are safe and widely used but lack definitive evidence of effectiveness 1

Surgical Referral: When Conservative Treatment Fails

Refer to orthopedic surgery if pain persists despite 3-6 months of well-managed conservative treatment. 1, 3

• Surgical intervention (typically arthroscopic subacromial decompression) should only be considered after failed conservative management 1
• Important caveat: There is no convincing evidence that surgical treatment for subacromial pain syndrome is more effective than conservative management 2
• If a full-thickness rotator cuff tear is identified and conservative treatment including prior steroid injections has failed, surgical repair becomes the primary treatment option, with 81% of surgical patients reporting excellent results versus only 37% with non-surgical treatment 3

Critical Pitfalls to Avoid

• Do not perform surgery for asymptomatic rotator cuff tears 3, 2
• Avoid opioids as first-line treatment—reserve strictly for rescue analgesia 3
• Do not rely on the Can test alone for diagnosis; use a combination of clinical tests 2
• Do not skip the 6-week conservative trial before considering injections or advanced imaging 2