Bones of the Forearm (humananatomywiki101.com)

Definition

  • Monteggia Fracture: Fracture of the ulnar shaft with associated radial head dislocation
  • Galeazzi Fracture: Fracture of the radial shaft between middle and distal third with associated distal radial-ulnar joint (DRUJ) disruption
  • Mnemonic: MUGR: Monteggia- Ulnar fracture, Galeazzi- Radius fracture

Mechanism

  • Monteggia
    • Fall onto outstretched and hyper-pronated hand
    • Direct blow to ulna or hyperextension injuries
  • Galeazzi
    • Direct trauma to the wrist
    • Fall onto outstretched and pronated hand

Epidemiology

  • Adults: Estimated 60% of forearm fractures involve both bones, 25% fracture of only the ulna, 15% fracture of only the radius (Sonin 2000, Smith 1957)
  • Exact incidence of Monteggia and Galeazzi fractures unknown
    • Galeazzi estimated to account for 3-7% of forearm fractures
    • Galeazzi fracture more common than Monteggia
  • Monteggia more common in children, peak incidence 4-10 years old

Physical Exam

  • Perform complete neurovascular exam in all patients concerning for either fracture
    • Monteggia: Most common nerve injury posterior interosseous nerve  (weakness with thumb extension)
    • Galeazzi: neurovascular injury is rare
  • Common to both fracture patterns are pain, elbow swelling, deformity, crepitus, painful and limited elbow ROM- especially pronation/supination
  • Assess compartments for signs of increased compartment pressure
  • ROM:  assess for pain or limited ROM in supination and pronation as a sign of possible instability in both fractures
  • DRUJ stress test: (for assessing for DRUJ instability in possible Galeazzi fractures)

X-Ray Findings

  • Monteggia
    • Ulna fracture is usually obvious. Avoid being distracted by this injury and missing the radial head dislocation
    • Check radio-capetellar line
        • Should intersect the capitellum regardless of angle of flexion/extension
        • If it does not, indicates radial head dislocation

Radiocapetellar Line (Normal + Abnormal)

(http://www.wikiradiography.net/)

  • Galeazzi
    • Radius fracture usually obvious
    • Check DRUJ
        • The distal radioulnar joint is normally 1-2mm, wider suggests ligamentous injury 
        • Look for associated ulnar styloid fracture which can also suggest DRUJ injury

(http://www.wikiradiography.net/)

Bado Classification for Monteggia Fractures (Case courtesy of Dr Benoudina Samir, Radiopaedia.org. From the case rID: 39720)

Fracture Classification System

  • Monteggia: Bado classification based on displacement of radial head
    • Type I: Ulnar shaft fracture with anterior dislocation radial head
    • Type II: Ulnar shaft fracture with posterior/posterolateral dislocation radial head
    • Type III: Ulnar shaft fracture with lateral/anterolateral dislocation radial head
    • Type IV: Ulnar shaft fracture with proximal shaft radial fracture at same level
  • Galeazzi:
    • Type I: Apex volar (dorsal displacement of distal radius)
    • Type II: Apex dorsal (volar displacement of distal radius)

Galeazzi Type I + II Fractures (Atesok 2011)

ED Management

  • General Care
    • Provide analgesia
    • Open fractures require immediate orthopedic consultation in the ED
    • All cases should be discussed with an orthopedist
    • If discharging from ED after reduction, all need close follow-up with orthopedics (within 1 week)
  • Monteggia Fracture-Dislocations
    • Pediatric Patients
      • Priority is closed reduction of radial head, often made difficult by associated plastic/greenstick deformity
      • Ensure anatomic alignment of the ulna and place in supinated long arm splint
      • Inability to reduce radial head: Discuss with orthopedics for prompt consultation in ED vs admission for OR vs transfer to pediatric orthopedic referral center
      • Usually managed conservatively if successful initial reduction.
    • Adult Patients
      • Priority is closed reduction of the radial head with attention to anatomic alignment of ulna with application of long arm splint
      • If unable to reduce radial head, orthopedic consult in ED
      • Managed with ORIF  <1 week follow-up with orthopedics necessary
  • Galeazzi Fractures
    • Pediatric Patients
      • Closed reduction of radius fracture and splinting with long arm splint in supination
      • Managed conservatively, if non-reducible or unstable may require ORIF
    • Adult Patients
      • Closed reduction of the radius followed by reduction of the ulna in the DRUJ, with application of long arm splint
      • If unable to reduce, orthopedic consult in ED
      • “Fracture of necessity”
        • Requires ORIF for acceptable outcome because of loss of stability at DRUJ and pull of forearm muscles causes loss of proper alignment in cast,
        • High (up to 90%) complications rates seen if treated nonoperatively (Perron 2001, Hughston 1957)

Prognosis

  • Misdiagnosis/ delayed diagnosis can lead to DRUJ instability, malunion, limited forearm ROM, chronic wrist pain, osteoarthritis, nerve injury
  • Better long-term outcomes seen in children compared to adults
  • Even with appropriate treatment, complications can include: PIN neuropathy (usually resolves), malunion, compartment syndrome, DRUJ subluxation

Take Home Points

  • Always suspect a Monteggia/ Galeazzi injuries when a forearm fracture is seen as missed diagnosis can lead to very poor outcomes
  • Radius Fracture: check for DRUJ injury
  • Ulna Fracture: check for radial head dislocation

Read More

Ortho Bullets: Galeazzi Fractures

Ortho Bullets: Monteggia Fractures

Radiopaedia: Bado Classification of Monteggia Fracture-Dislocations

Core EM: Compartment Syndrome

References

Atesok KI et al. Galeazzi Fracture. J Am Acad Orthop Surg 2011; 19(10): 623-33. PMID: 21980027

Delpont M et al. Monteggia injuries. Orthop Traumatol Surg Res. 2017. PMID: 29174872

Egol KA et al. Handbook of Fractures 4th ed. Lipincott 2010: 261-268

George AV, Lawton JN. Management of complications of forearm fractures. Hand Clin. 2015; 31 (2): 217-33. PMID: 25934198

Hughston JC. Fracture of the distal radial shaft: mistakes in management. J Bone Joint Surg Am 1957; 39:249-264. PMID: 13416321

Johnson NP, Smolensky A. Fracture, Galeazzi. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2017 Jun-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470188/ PMID: 29262123

Perron AD et al. Orthopedic pitfalls in the ED: Galeazzi and Monteggia fracture-dislocation. Am J Emerg Med. 2001;19(3):225-8. PMID: 11326352

Smith H, Sage F P. Medullary fixation of forearm fractures.  J Bone Joint Surg 1957; 39 91-98. PMID: 13385267

Sonin A. Fractures of the elbow and forearm. Semin Musculoskelet Radiol. 2000; 4(2): 171-91. PMID: 11061700