Introduction
  • Represent 1% of elbow fractures
    • occur in coronal plane
    • very little soft tissue attachment so they often displace
  • Mechanism
    • fall on outstretched hand
Classification
  • Bryan and Morrey classification
    • Type I: (Hahn-Steinthal fracture)
      • complete fracture of capitellum
    • Type II: (Kocher-Lorenz fracture)
      • Superficial osteochondral fracture fragment
    • Type III
      • comminuted
  • McKee modification
    • Type IV
      • coronal shear fracture including capitellum and trochlea
      • "double bubble" seen on lateral radiograph representing the capitellum and trochlea
Presentation
  • Symptoms
    • elbow pain, swelling, and stiffness
  • Physical exam
    • may have mechanical block
Imaging
  • Radiographs
    • best demonstrated on lateral radiograph
  • CT
    • obtain CT scan to delineate fracture anatomy
Treatment
  • Nonoperative
    • posterior splint immobilization for 3 weeks
      • indications
        • nondisplaced (< 2mm) Type I fractures
        • nondisplaced (< 2mm) Type II fractures
  • Operative
    • open reduction and internal fixation
      • indications
        • displaced Type I fractures
        • Type IV fractures
      • technique
        • screw fixation (may use headless Herbert screw)
        • avoid disruption of the blood supply that comes from the posterolateral aspect of the elbow
      • fixation should allow early ROM
    • fragment excison
      • indications
        • displaced (>2mm) Type II fractures
        • displaced (>2mm) Type III fractures
      • contraindicated if other injuries that may create instability
Complications
  • Complications of operative treatment
    • nonunion (1-11% with ORIF)
    • ulnar nerve injury
    • heterotopic ossification (4% with ORIF)
    • AVN of capitellum