What is the best course of action for an adult patient with a history of physical activity, presenting with shoulder pain upon abduction and external rotation, radiating down to the middle of the forearm?

Shoulder Pain with Abduction/External Rotation and Forearm Radiation

Begin with standard three-view shoulder radiographs (AP in internal rotation, AP in external rotation, and axillary or scapula-Y view) to rule out fracture or dislocation, then proceed to MRI without contrast if radiographs are negative, as this presentation suggests rotator cuff pathology with possible nerve involvement. 1, 2

Initial Diagnostic Approach

Mandatory Radiographic Evaluation

• Obtain upright radiographs with three standard views as the first imaging study, since radiography effectively identifies fractures and shoulder malalignment that require immediate intervention 3, 1
• The axillary or scapula-Y view is non-negotiable—glenohumeral and acromioclavicular dislocations are frequently misclassified when only AP views are obtained 3, 1, 2
• Upright positioning is essential because supine radiographs underrepresent shoulder malalignment 3, 2

Advanced Imaging When Radiographs Are Normal

• If radiographs show no fracture or dislocation, proceed directly to MRI without contrast (rated 9/9 appropriateness) to evaluate suspected rotator cuff pathology, which is the most likely diagnosis given your clinical presentation 2, 4
• MRI without contrast is superior for detecting rotator cuff tears, tendinopathy, and associated soft tissue injuries that cause pain with abduction and external rotation 2
• Ultrasound is an acceptable alternative if local expertise is available (also rated 9/9), though MRI provides more comprehensive soft tissue evaluation 2

Clinical Reasoning for This Presentation

Why Rotator Cuff Pathology Is Most Likely

• Pain during abduction with external rotation is the classic presentation for rotator cuff dysfunction and secondary impingement syndrome 3, 4
• The radiation down to the middle of the forearm suggests either referred pain from rotator cuff pathology or possible nerve involvement (C5-C6 radiculopathy or suprascapular nerve irritation) 5
• Rotator cuff injuries commonly present with focal weakness and decreased range of motion during abduction with external or internal rotation 3

Key Physical Examination Findings to Document

• Assess for focal weakness specifically during abduction and external rotation maneuvers 3
• Evaluate shoulder motion, flexibility, and strength to characterize the severity 3
• Test for pain location—anterior or anterolateral shoulder pain suggests impingement or rotator cuff pathology 3
• Document whether pain occurs during specific phases of arm movement (elevation, deceleration) 3

Management Algorithm

Conservative Treatment (First-Line)

• Most soft-tissue injuries including rotator cuff tears can undergo conservative management before considering surgery 3
• Initiate rest from aggravating activities until asymptomatic 3
• Prescribe physical therapy focused on rotator cuff and scapular stabilizer strengthening 3
• Consider NSAIDs for pain control and potentially subacromial corticosteroid injections if conservative measures provide insufficient relief 5
• Rehabilitation should restore range of motion and re-establish proper shoulder mechanics over 1-3 months depending on severity 3

Indications for Urgent Surgical Referral

• Unstable or significantly displaced fractures identified on radiographs require acute surgical management 3
• Joint instability confirmed on imaging necessitates urgent orthopedic evaluation 3

Critical Pitfalls to Avoid

• Never skip the axillary or scapula-Y view—over 60% of posterior dislocations are initially missed without proper orthogonal views 1
• Do not attempt any reduction maneuvers without radiographic confirmation, as this could worsen fracture-dislocations 1
• Avoid ordering CT as the initial study—it is inferior to MRI for soft-tissue shoulder injuries and should be reserved for characterizing complex fracture patterns when surgical planning is needed 3, 2
• Do not dismiss the possibility of cervical radiculopathy—sharp or burning pain is commonly radicular in origin, whereas rotator cuff tendinitis produces dull, diffuse, aching pain 5
• In older patients, maintain high suspicion for complete rotator cuff tears that may require earlier surgical intervention rather than prolonged conservative management 1