Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon

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Monteggia Fracture

  • Because the radius and ulna are bound by ligaments and an interosseous membrane, a displaced fracture of the ulna often is accompanied by dislocation of the radial head, a combination termed a Monteggia fracture.
  • The diagnosis sometimes is missed because the dislocation can be overlooked.
  • Reduction of both the fracture and the dislocation must be achieved.
  • Bado classification:
    • Most commonly used system
    • Based on the direction of the dislocation of the radial head, which is the same as the direction of the apex of the ulnar fracture
    • 4 types:
      • I: Anterior dislocation of the radial head (most common type)
      • II: Posterior dislocation of the radial head
      • III: Lateral dislocation of the radial head (2nd most common pattern in childhood)
      • IV: Anterior dislocation of the radial head in combination with a proximal radial fracture
Fracture occurrence is distributed evenly between males and females.
  • Relatively uncommon
  • Peak incidence: Ages 4-10 years
  • However, this fracture may occur at any age, including adulthood.
  • Most common in children: Bado type-I fractures, with plastic deformation of the ulna.
  • Most common in adults: Bado type I and type II fractures
Risk Factors
Any child or adult with a fracture of the proximal or middle of the ulnar shaft should be considered at risk for this fracture.
  • The ligamentous connections between the radius and ulna cause the radial head dislocation to occur when the ulna fractures, or vice versa.
  • Type I fracture mechanism: Hyperpronation or hyperextension
  • Type II fracture mechanism: Axial loading of a partially flexed elbow
Signs and Symptoms
  • Signs:
    • Swelling in the forearm and elbow
    • In cases diagnosed late, a bump may be present over the elbow at the time a cast is removed for treatment of an ulnar fracture, indicating the dislocated radial head.
  • Symptoms:
    • Acutely, tenderness over the elbow and deformity
    • If diagnosed late, the unreduced radial head could block the full range of flexion or extension or cause clicking with pronation and supination.
Physical Exam
  • In acute cases, diagnosis should be made primarily by radiography showing both the ulnar fracture and the radial head dislocation.
  • In chronic cases, a prominence of the radial head is visible when the arm is out of the cast.
    • This prominence represents the dislocated radial head and may be compared with the opposite side.
  • Radiography:
    • Plain radiographs are sufficient for diagnosis.
    • All forearm fractures should include visualization of the elbow and wrist joints.
    • These radiographs should be true AP and lateral views.
      • If they cannot be obtained on the same film, separate films of these regions should be ordered.
      • The physician should be available to help in positioning, if needed.
  • MRI is not required for diagnosis.
Pathological Findings
  • At the time of injury, the annular ligament of the radius is torn and becomes infolded.
  • If the radial head remains unreduced for several years, it degenerates because the cartilage wears away.
Differential Diagnosis
  • An isolated ulnar fracture may occur without radial head dislocation.
  • The status of the radial head may be determined by drawing a line on the radiograph through the radial shaft.
    • This line should fall in the center of the capitellum of the distal humerus.
  • An isolated radial head dislocation may occur, but it is rare.
  • Congenital dislocation of the radial head does occur.
    • May be distinguished by changes in the shape of the radial head: Overgrowth and loss of the normal concave reciprocal articular surface.
General Measures
  • For children, closed reduction usually is successful for treating both the dislocated radial head and the ulnar fracture.
  • The mechanism used to reduce the ulnar fracture also is used to maintain reduction of the radial head fracture.
    • Type I fractures: The forearm should be in supination to midposition, and the elbow should be in flexion of >110°.
    • Type II fractures: The elbow should be in extension.
  • In both type I and type II fractures, the radial head may require a push to place it properly.
  • An above-the-elbow cast should be applied, and a bivalved cast should be used if substantial swelling is present.
  • A radiograph should be obtained after reduction to confirm that alignment is satisfactory.
  • Unstable or displaced fractures after reduction:
    • In children: Require open reduction and fixation
    • In adults: Require open reduction and internal fixation
  • Follow-up in 1 week
  • Late detection of a Monteggia fracture:
    • 1-3 weeks after injury, the radial head may require open reduction, even in children.
    • >3 weeks after injury, reconstruction of the annular ligament of the radial head may be necessary.
Special Therapy
Physical Therapy
  • Adults often need therapy to regain optimal motion.
  • In children, physical therapy is not needed because parents can do the necessary exercises with them.
  • If the ulnar fracture cannot be maintained or reduced, open reduction and internal fixation should be performed, which usually causes the radial head to become and remain reduced.
  • If it is not reduced, then an open reduction of the radial head should be performed.
  • In a child, internal fixation of the ulna may be done with an intramedullary nail if closed reduction has failed.
  • In adults, a Monteggia fracture should be treated directly with open reduction and internal fixation (rigid plate and screws) of the ulna.
    • Radial head reduction only if needed
  • Late reconstruction of the annular ligament of the ulna is done using the Bell-Tawse technique.
    • A strip of triceps fascia is used to reconstruct the ligament and is anchored to the ulna.
  • In children, immobilization is continued for 6 weeks.
  • In adults, because of a greater risk of stiffness, carefully supervised ROM may be started earlier.
Issues for Referral
Monteggia fractures should be referred to an orthopaedic surgeon promptly to ensure timely and adequate reduction.
  • With careful reduction and follow-up, the prognosis is good.
  • Stable injuries in children have an excellent prognosis with closed treatment.
  • Bado type I injuries are thought to have a worse prognosis.
  • Injuries that are associated with coronoid or radial head fracture also have poorer outcomes.
  • Patients with missed injuries have a poorer prognosis.
  • Results of late reconstruction are unpredictable.
  • Redislocation
  • Stiffness
  • Proximal radioulnar synostosis
  • Elbow instability
  • Nerve injury (usually radial) at time of radial head dislocation
Patient Monitoring
  • The patient should be seen 1 week after injury to rule out redisplacement.
  • Additional follow-up should be continued until ROM is satisfactory.
  • 813.03 Closed Monteggia fracture
  • 813.13 Open Monteggia fracture
Patient Teaching
  • At the time of initial consultation, patients should be counseled about the risk of redislocation.
  • Such counseling helps encourage compliance with follow-up care and exercises.
Q: What is the prognosis of a Monteggia fracture in a child?
A: The prognosis of stable fractures treated without surgery is excellent. Missed fractures that are displaced have a much poorer outcome.

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