Rotator Cuff Injury

Snapshot

• A 50-year-old woman reports shoulder pain that has worsened over the past year. She states that she has difficulty sleeping at night on the right side and experiences significant pain in the right arm when reaching over her head. On physical exam, the empty can test is positive. She is referred for physical therapy and given ibuprofen for pain management.

Introduction

• Clinical definition
  • injury to one or more of the rotator cuff muscles
    • injury is typically due to tear or tendinopathy
    • rotator cuff muscles, which are all innervated by C5 and C6, are the SITS 
      • Supraspinatus
        • innervation
          • suprascapular nerve 
        • function
          • initial abduction of the arm (0-15°)
      • Infraspinatus
        • innervation
          • suprascapular nerve
        • function
          • lateral rotation of the arm
      • Teres minor
        • innervation
          • axillary nerve 
        • function
          • adduction and lateral rotation of the arm
      • Subscapularis
        • innervation
          • upper and lower subscapular nerves
        • function
          • adduction and medial rotation of the arm
• Epidemiology
  • incidence
    • the supraspinatus muscle is most commonly injured
  • demographics
    • adults
  • risk factors
    • older age
    • smoking
    • repetitive overhead reaching
• Pathogenesis
  • acute avulsion injuries
    • typically following trauma
  • chronic degenerative tears
    • repetitive overhead motions
    • tendon weakening due to degenerative changes and chronic impingement
• Associated conditions
  • biceps tendinopathy
  • osteoarthritis
• Prognosis
• re-tear may occur

Presentation

• Symptoms
  • shoulder pain
    • exacerbated by
      • sleeping on the affected shoulder
      • reaching overhead
  • limited function of the shoulder
• Physical exam
  • severe focal tenderness at the insertion of supraspinatus (anterolateral shoulder)
  • decreased active elevation with normal passive range of motion
  • Hawkins impingement test 
    • passive internal rotation of the shoulder with the patient seated and elbow flexed 90°
    • test is positive if there is pain
  • Neer impingement test 
    • passive elevation of the arm while internally rotated with the patient standing
    • test is positive if there is pain
  • painful arc sign 
    • pain with active abduction between 60° and 120°
  • empty can test  
    • patient with arm elevated to 90° with elbow extended and thumbs down
      • clinician applies a downward force on the arm while patient resists
    • test is positive if there is pain
• 90% specificity for supraspinatous pathology

Imaging

• Radiographs
  • indication
    • for all patients as initial imaging
  • finding
    • loss of subacromial space, due to upward migration of humeral head
• Magnetic resonance imaging (MRI) 
  • indications
    • if radiography is normal but there is suspicions for rotator cuff injury
    • not indicated for all patients
• most accurate test

Studies

• Making the diagnosis
• most cases are clinically diagnosed

Differential

• Adhesive capsulitis 
  • distinguishing factor
• active and passive range of motion are limited

Treatment

• Conservative
  • physical therapy
    • indication
      • for all patients
• Medical
  • nonsteroidal anti-inflammatory drugs (NSAIDs)
    • indications
      • for all patients
      • pain management
  • steroid injections
    • indication
      • for patients who fail NSAIDs as pain management
• Operative
  • surgical repair
    • indications
      • for patients with complete tears
• for patients who fail all other more conservative management of 3-6 months

Complications

• Functional limitations
• Adhesive capsulitis