What is the differential diagnosis (DDX) and management for a patient with restricted range of motion (ROM) of the shoulder with pain for over 6 weeks?

Differential Diagnosis for Restricted Shoulder ROM with Pain >6 Weeks

For shoulder pain and restricted range of motion persisting beyond 6 weeks, the primary differential diagnoses are adhesive capsulitis (frozen shoulder), rotator cuff pathology (tendinopathy or tear), subacromial impingement syndrome, glenohumeral osteoarthritis (if >50 years), and acromioclavicular joint arthritis. 1

Key Differential Diagnoses

Adhesive Capsulitis (Frozen Shoulder)

• Hallmark finding: globally restricted passive range of motion in all planes, particularly external rotation and abduction 1
• Diffuse shoulder pain that is typically worse at night 1
• Strong association with diabetes mellitus and thyroid disorders—screen for these conditions 1
• Critical pitfall: This develops in up to 72% of patients with prolonged immobilization, so early mobilization is mandatory 2

Rotator Cuff Pathology (Tendinopathy or Tear)

• Pain specifically with overhead activities 1
• Clinical decision rule for rotator cuff tear: positive if pain with overhead activity + weakness on empty can test + weakness on external rotation test + positive impingement sign 1
• Painful arc between 60-120° of abduction/flexion is pathognomonic for subacromial pathology 2
• Most common clinical diagnosis in primary care physiotherapy (48% after history, 39% after examination) 3

Subacromial Impingement Syndrome

• Pain during overhead movements, particularly in the 60-120° arc 2
• Positive impingement signs (Neer or Hawkins-Kennedy tests) 1
• May coexist with rotator cuff tendinopathy 3

Glenohumeral Osteoarthritis

• In patients >50 years: presents as gradual pain with progressive loss of motion 1
• In patients <40 years: consider glenohumeral instability with history of dislocation/subluxation events and positive apprehension/relocation tests 1

Acromioclavicular Joint Arthritis

• Superior shoulder pain localized to AC joint 1
• Tenderness directly over AC joint on palpation 1
• Positive cross-body adduction test (pain when arm is brought across chest) 1

Cervical Radiculopathy

• Must be excluded: cervical spine pathology can cause both shoulder pain and restricted ROM that mimics intrinsic shoulder disorders 4
• Look for neck pain, paresthesias, dermatomal sensory changes, or reflex abnormalities 4

Diagnostic Algorithm

Step 1: Initial Imaging

Obtain three-view radiographs immediately: AP in internal rotation + AP in external rotation + axillary or scapula-Y view 2

• Must be performed upright (supine positioning misses malalignment) 2
• The axillary or scapula-Y view is essential—dislocations are frequently missed on AP views alone 2
• Plain radiographs help diagnose massive rotator cuff tears (superior humeral head migration), shoulder instability, and arthritis 1

Step 2: Advanced Imaging (If Diagnosis Unclear or Conservative Management Fails)

• MRI without contrast: appropriate for rotator cuff pathology when conservative management is planned 2, 1
• MR arthrography: gold standard for labral tears, SLAP lesions, and partial rotator cuff tears 2, 1
• Ultrasound: acceptable alternative for rotator cuff evaluation 1, 3
• CT without contrast: reserved for complex fracture characterization 2

Management Approach

Conservative Management (First-Line for Most Diagnoses)

Initiate NSAIDs, ice, and early mobilization immediately for soft-tissue injuries 2

For Adhesive Capsulitis:

• Passive and active-assisted range of motion exercises focusing on external rotation and abduction 5
• Gentle mobilization and stretching exercises 5
• Analgesics (acetaminophen or ibuprofen) if no contraindications 5
• Corticosteroid injections combined with physical therapy 6

For Rotator Cuff Pathology/Impingement:

• Physical therapy emphasizing rotator cuff and scapular stabilizer strengthening 7, 6
• Corticosteroid injections for pain control 6
• Progressive active ROM as alignment improves and strength returns 5

For AC Joint Arthritis:

• NSAIDs and activity modification 6
• Corticosteroid injection into AC joint 6

When to Refer for Surgical Evaluation

• No improvement after 3-4 weeks of conservative management 2
• Unstable or significantly displaced fractures on radiographs 2
• Joint instability (dislocation) 2
• Massive rotator cuff tears may require expedited surgical timeline for optimal outcomes 2
• If physiotherapy shows no benefit after 12 weeks, refer back to orthopedic surgeon 3

Critical Pitfalls to Avoid

• Never immobilize the shoulder for prolonged periods—this causes adhesive capsulitis in up to 72% of cases 2
• Do not rely on AP radiographs alone—dislocations are frequently missed without axillary or scapula-Y views 2
• Always consider cervical radiculopathy in the differential—it can mimic intrinsic shoulder pathology 4
• Screen for diabetes and thyroid disease in patients with adhesive capsulitis 1
• If treatment shows no benefit, do not continue indefinitely—41% of patients in primary care were still receiving treatment at 12 weeks without improvement 3