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Anterior Glenohumeral Instability  

Pathology

Bankart lesion

  • Inferior & middle glenohumeral ligament labral avulsion
    • First described by Perthes (1906) & popularised by Bankart (1938)
  • Bony avulsion may be present
    • > 85% TUBS have Bankart lesion (Rowe, 1978)

Bony involvement

  • Glenoid Rim Avulsions
      • Usually part of Bankart lesion
      • Management
        • Reattach if large
        • Ignore if small
      • May see erosions with repeated dislocations
  • Hill Sachs Lesion
    • Osteochondral lesion in posterosuperior humeral head
    • Impaction of humeral head against the glenoid rim in anterior dislocation
    • Reverse lesion seen anteriorly with posterior dislocation
    • Result of initial dislocation
    • May produce subsequent dislocations as defect lies in glenoid cavity when shoulder abducted & externally rotated

Muscle

  • Uncommon cause of instability
  • Cuff Tears
    • Subscapularis may be torn & contribute to instability
    • Cuff tears seen with dislocations in older age groups
      • > 40 years 30%
      • > 60 years 80%
  • Present as pain or weakness
  • Rotator interval may be ↑
  • Between Supraspinatus & Subscapularis
  • Tends to open up with AMBRI