Subacromial impingement

Two types

Outlet Subacromial Impingement

  • Outlet impingement is the first stage of rotator cuff disease which is a continuum progressing from partial to full-thickness to massive rotator. cuff tears, and finally to rotator cuff tear arthritis


  • Symptoms
    • insidious onset of pain exacerbated by overhead activities
    • night pain
      • poor indicator of successful nonoperative management
  • Physical exam
    • impingement tests


  • Radiographs
  • MRI
    • useful in evaluating the degree of rotator cuff pathology


  • Nonoperative
    • physical therapy, oral anti-inflammatory medication, subacromial injections
      • Techniques
        • aggressive rotator cuff strengthening and periscapular stabilizing exercises
        • an integrated rehabilitation program is indicated in the presence of scapular dyskinesia which aims to regain full shoulder range of motion and coordinate the scapula with trunk and hip motions
  • Operative
    • Arthroscopic subacromial impingement and acromioplasty
      • indications
        • subacromial impingement syndrome that has failed a minimum of 4-6 months of nonoperative treatment

Internal Subacromial Impingement

  • Internal impingement refers to pathology on undersurface of rotator cuff
    • in contrast to subacromial or “external” impingement which occurs on bursal side of rotator cuff)
    • internal impingement covers a spectrum of injuries including
      • fraying of posterior rotator cuff
      • posterior and superior labral lesions
      • hypertrophy and scarring of posterior capsule glenoid (Bennet lesion)
      • cartilage damage at posterior glenoid


  • Nonoperative
    • posterior capsule stretching physiotherapy for 6 months
      • indications
        • most internal impingement can be treated non-operatively
      • technique
        • posterior capsule stretching with sleeper stretches
        • rotator cuff stretching and strengthening
  • Operative
    • arthroscopic debridement  and/or repair of rotator cuff tear and labrum 
      • indications
        • failed nonoperative treatment
        • partial thickness rotator cuff tear (PASTA) compromises the integrity of the rotator cuff
          • partial rotator cuff tears >50%