What is the comprehensive approach to diagnosing and managing shoulder pain, including physical examination, differential diagnosis (DD), imaging, and treatment options, including when to consider regenerative medicine, such as platelet-rich plasma (PRP) therapy?

Comprehensive Approach to Shoulder Pain

The optimal approach to shoulder pain requires systematic physical examination focusing on specific provocative tests (Neer's, Hawkins, painful arc, empty can, and external rotation resistance tests), followed by appropriate imaging (plain radiographs first, then MRI without contrast for persistent symptoms), and treatment beginning with conservative measures (NSAIDs, physical therapy with eccentric exercises) before considering surgical options or regenerative medicine, which should only be considered after failure of standard treatments. 1

Initial Assessment and Physical Examination

History Taking

• Onset: Acute (trauma) vs. insidious (degenerative)
• Location and radiation pattern of pain
• Aggravating and alleviating factors
• Previous treatments and response
• Functional limitations
• Red flags: Night pain, weight loss, fever (possible malignancy or infection)

Physical Examination

1. Observation: Assess posture, muscle atrophy, and scapular winging
2. Palpation: Identify tender areas (AC joint, bicipital groove, subacromial space)
3. Range of Motion: Active and passive in all planes
4. Special Tests:
   • Impingement Tests:
     • Neer's test (88.7% sensitivity, 33% specificity) 1
     • Hawkins test
     • Painful arc test
   • Rotator Cuff Tests:
     • Empty can test (supraspinatus)
     • External rotation resistance test (infraspinatus)
     • Lift-off test (subscapularis)
   • Instability Tests:
     • Apprehension test
     • Relocation test
     • Load and shift test
   • Labral Tests:
     • O'Brien's test
     • Crank test
     • Biceps load test
5. Cervical Spine Examination: Essential to rule out referred pain 2
6. Neurovascular Assessment: Check for thoracic outlet syndrome and peripheral nerve involvement

Differential Diagnosis

Common Causes

• Rotator cuff disorders (tendinopathy, partial/full tears) - 10% of shoulder pain 3
• Subacromial impingement syndrome
• Adhesive capsulitis (frozen shoulder) - 6% of shoulder pain 3
• Glenohumeral osteoarthritis - 2-5% of shoulder pain 3
• Labral tears (SLAP, Bankart)
• Acromioclavicular joint pathology
• Biceps tendinopathy

Less Common Causes

• Referred pain from cervical spine 2
• Thoracic outlet syndrome 2
• Neurological conditions (suprascapular neuropathy)
• Visceral referred pain (cardiac, pulmonary, diaphragmatic) 2
• Inflammatory arthropathies
• Neoplasms 2

Imaging

First-Line Imaging

• Plain Radiographs: Minimum 3 views 1
  • Anteroposterior (AP) view
  • External rotation view
  • Axillary or scapular Y view
  • Purpose: Rule out fractures, arthritis, calcifications

Second-Line Imaging (for persistent symptoms)

• MRI without contrast: Preferred for soft tissue pathology 1
  • High sensitivity for rotator cuff tears and muscle pathology
  • Moderate sensitivity for labral tears

Advanced Imaging (when indicated)

• MR Arthrography: Gold standard for labral tears (86-100% sensitivity) 1
  • Particularly valuable in patients under 35 years
  • Best for subacute or chronic settings
• CT Arthrography: Alternative when MRI is contraindicated 1
• Ultrasound: Limited role for labral tears but useful for rotator cuff and biceps tendon evaluation 1

Management Approach

Phase 1: Conservative Management (0-6 weeks)

1. Pain Management:

   • NSAIDs as first-line medication (taper as tolerated) 1
   • Activity modification
   • Ice/heat therapy

2. Physical Therapy (Initial Phase):

   • Pain control measures
   • Gentle range of motion exercises
   • Proper positioning education
   • Isometric exercises if pain-free 1

3. Injections (if significant pain persists):

   • Corticosteroid injections (limit to 3-4 per year) 1
   • Consider ultrasound guidance for accuracy

Phase 2: Progressive Rehabilitation (6 weeks-3 months)

1. Advanced Physical Therapy:

   • Progressive ROM exercises
   • Light strengthening for rotator cuff and periscapular muscles
   • Scapular stabilization exercises 1

2. Functional Restoration:

   • Activities mimicking daily tasks
   • Kinetic chain strengthening
   • Proprioception and neuromuscular control exercises 1

3. Reassessment: Clinical evaluation at 6 weeks to assess progress 1

Phase 3: Advanced Rehabilitation and Decision Point (3+ months)

1. Advanced Rehabilitation (if improving):

   • Progressive resistance training
   • Advanced scapular stabilization
   • Sport or activity-specific training 1

2. Surgical Consideration (if not improving):

   • Repeat imaging or surgical consultation if symptoms persist after 3 months of appropriate treatment 1
   • Consider earlier surgical referral for:
     • Patients under 30 years
     • High-demand or contact sport participants
     • Evidence of significant Hill-Sachs lesion or Bankart tear 1

Surgical Options (when indicated)

• Arthroscopic subacromial decompression
• Rotator cuff repair
• Labral repair
• Capsular release (for adhesive capsulitis)
• Arthroplasty (for advanced glenohumeral arthritis)

Regenerative Medicine Considerations

Regenerative medicine options should only be considered after failure of standard treatments and when surgery is not indicated or desired. Current evidence is still evolving, but these approaches may be considered in specific scenarios:

• Platelet-Rich Plasma (PRP): May be considered for:

  • Partial rotator cuff tears
  • Rotator cuff tendinopathy resistant to conventional therapy
  • Post-surgical augmentation

• Stem Cell Therapy: Limited evidence but may be considered for:

  • Degenerative rotator cuff disease
  • Early osteoarthritis

Follow-up Protocol

• Initial follow-up: 1-2 weeks after treatment initiation 1
• Clinical reassessment: 6 weeks 1
• Rehabilitation progress evaluation: 3 months 1
• Consider repeat imaging or surgical consultation if symptoms worsen or don't improve by 3 months 1

Common Pitfalls and Caveats

• Failure to assess the cervical spine can lead to missed diagnosis of referred pain
• Isolated anterosuperior labral tears are difficult to diagnose clinically and often missed 1
• Relying on a single special test rather than a combination of tests reduces diagnostic accuracy
• Overuse of corticosteroid injections can lead to tendon weakening 1
• Persistent shoulder pain without discernible musculoskeletal abnormalities should prompt investigation for non-musculoskeletal causes 2