Monteggia Fracture

Key Points:

  • Must have high index of suspicion – high incidence of missed injuries (Waters, 2010)
  • Appropriate radiographic imaging is essential to making the correct diagnosis
  • Be aware of plastic deformation of the ulna

Description:

  A Monteggia fracture involves a fracture of the ulna with disruption of the proximal radio-ulnar joint (PRUJ) and radiocapitellar dislocation (Bado, 1967).  Proximal radius dislocations in skeletally immature teenagers and children occur in the setting of a spectrum of ulnar injuries that often do not follow classic adult patterns. 

Epidemiology:

  Monteggia fractures account for 0.4% of all forearm fractures in children.  This fracture pattern was first described in 1814 by Giovanni Monteggia. They typically occur in children between 4 and 10 years of age after a fall onto an outstretched hand.  The type of fracture depends largely on the mechanism of injury (Evans, 1949).

Clinical Findings:

  Patients usually present with a history of a fall onto an outstretched hand and pain in the forearm and elbow. Forearm deformity may or may not be present and limitations in range of motion are not always obvious.  Neurologic deficit is present at presentation in 10-20% of the cases.  This includes posterior interosseous nerve (PIN) and ulnar nerve neuropraxia, typically seen with Bado III and II, respectively (Waters, 2012).

Imaging Studies:

  Appropriate imaging is essential to avoid missing this injury.  AP and lateral films of the forearm as well as the elbow and wrist should be obtained.  Radiocapitellar alignment should be checked on all views and the radial shaft should point to the center of the capitellum in all positions on any radiographic view.  Beware of plastic deformation of the ulna, which can be easily missed but still associated with radiocapitellar dislocation.  When unclear, obtaining an AP and lateral x-ray of the contralateral elbow can be helpful.  Dynamic imaging with fluoroscopy may be helpful as well. Proximal radius dislocations can also occur with mid-shaft forearm fractures.  Clinical diagnosis can be missed in the subtle ulna plastic deformation fracture and significantly displaced radius and ulna shaft fractures (Bae, 2016).  Non-pediatric orthopedic surgeons and emergency room/urgent care providers may not recognize the presence of a proximal radius dislocation because there may be no obvious ulnar fracture or all attention is focused on the more visible displaced fractures.

Etiology:

Monteggia fractures typically occur from a fall on an outstretched hand.  The classification of injury is based on the direction of radial head dislocation which follows the apex of the ulnar fracture.  The classification pattern was originally described by Bado in 1967.

 

Bado Classification System


Type I
These are the most common pattern; accounting for 70-75% of all injuries.  There is an anterior radial head dislocation with apex anterior ulnar angulation. They are usually the result of a fall onto an outstretched hand with the forearm in pronation.
Type II
These are rare in children, accounting for only 3-6% of all injuries.   The radial head dislocates posterior and there is apex posterior angulation of the ulna.  These are the result of an axial load onto a partially flexed elbow or direct trauma to a proximal supinated forearm (Penrose, 1951).
Type III
This is the second most common pattern accounting for 15-20% of all injuries.  It is characterized by lateral radial head dislocation and a varus angulated (apex lateral) proximal ulna fracture.  These occur as a result of a fall onto an outstretched hand with the forearm in pronation and an associated varus stress.
Type IV
This is characterized by an anterior radial head dislocation in the setting of proximal 1/3 transverse fractures of the radius and ulna. These are the result of a fall onto an outstretched hand with the forearm in pronation, and are usually obtained via a higher energy mechanism.

  A Monteggia fracture dislocation should be distinguished from a congenital radial head dislocation. Children may present with new trauma and elbow pain in the setting of a congenital radial head dislocation.  Radiographs will generally show a hypoplastic capitellum with a convex radial head that is usually dislocated posteriorly.  If clinical question remains about the underlying diagnosis, radiographs of the contralateral elbow may be useful as congenital dislocations are often bilateral.  Most congenital radial head dislocations will be posterior, as opposed to traumatic dislocations which are mostly anterior (Waters, 2012).

Treatment:

  There are 3 important things to keep in mind when treating a monteggia fracture.  You must correct the ulna deformity, reduce the radial head, and minimize future forces that may cause the radial head to re-dislocate.  

  Treatment is often dictated by the pattern of the ulna fracture (Ring, 1998; Ramski, 2015).  Plastic deformation and incomplete fractures of the ulna can be treated with closed reduction of the ulnar bow and cast immobilization.  If the radial head cannot kept reduced in a safe position of elbow flexion, ideally less than 100 degrees, the ulna will require stabilization. Non-surgical management of the ulna is possible but close monitoring is required the first several weeks after manipulation (Foran, 2017). Complete transverse or short oblique fractures can be treated with closed reduction +/- intramedullary Kirschner wire fixation of the ulna depending on the stability of the radial head after reduction.  Long oblique or comminuted fractures of the ulna may require open reduction and internal fixation with plates and screws.  If radial head reduction is not maintained, stable internal fixation may be safely performed up to several weeks after the injury with good outcomes.  
If the radial head remains irreducible or unstable after fixation of the ulna, it may be necessary to perform an open reduction and remove or repair any interposed soft tissues.  This can be accomplished through a Kocher or posterolateral approach.  The forearm should be kept in pronation during the approach to avoid injury to the posterior interosseous nerve.  Open reduction and reconstruction of the annular ligament are rarely needed in the acute period.

Complications:

  Complications range from mild to severe.  Failure to recognize a monteggia fracture can have severe consequences.  Late reconstruction is difficult and often results in less than perfect results (Rang, 2005).  Options for treatment include open ulnar osteotomy with rigid plate fixation with or without open reduction of the radiocapitellar joint and annular ligament repair or reconstruction (Waters 2012).  Results are less predictable when the radial head has become deformed.
  Approximately 10% of these injuries have a transient PIN neuropraxia that resolves without treatment.  
  Elbow stiffness can be a problem with prolonged immobilization and is more frequently a problem in the setting of missed injury and delayed reconstruction.  
Although not a frequent complication, compartment syndrome has been described and should be considered by anyone taking care of these injuries.

References:

  1. Bado JL. The Monteggia lesion. Clin Orthop Relat Res. 1967; 50:71-86.
  2. Bae, D. Successful strategies for managing Monteggia Injuries.  J Pedtiatr Orthop 2016; 35:S67-S70.
  3. Evans EM. Pronation injuries of the forearm, with special reference to the anterior Monteggia fracture. J Bone Joint Surg Br. 1949;31B:578-88.
  4. Foran, I., Upasani, V., Wallace, C., et.al. Acute pediatric Monteggia fractures: A 
  5. conservative approach to stabilization. J Pediatr Orthop 2017: 37(6): e335-e341.Penrose JH. The Monteggia fracture with posterior dislocation of the radial head. J Bone Joint Surg Br. 1951;33:65-73.
  6. Ramski, D., Hennrikus, W., Bae, D., et. al.  Pediatric Monteggia fractures: a multicenter examination of treatment strategy and early clinical and radiographic results. J Pediatr Orthop 2015; 35 (2) 115-120.
  7. Rang, M., Pring, M. E., & Wenger, D. R. (2005). Rang's children's fractures.
  8. Ring D, Jupiter JB, Waters PM. Monteggia fractures in children and adults. J Am 
  9.       Acad Orthop Surg 1998; 6(4):215-24. 
  10. Speed JS, Boyd HB: Treatment of fractures of ulna with dislocation of head of radius (Monteggia fracture). JAMA 1940;115:1699-1705.
  11. Waters PM. Monteggia fracture-dislocation in children. In: Beaty JH, Kasser JR, eds. Fractures in children. 7th ed. Philadelphia: Lippincott Williams & Wilkins; 2010: 446-74.
  12. Waters PM, Bae DS, eds. Pediatric hand and upper limb surgery: a practical guide. Philadelphia: Lippincott Williams & Wilkins; 2012: 351-65.

Top Contributors:

Mathilde Hupin Debeurme MD
Jennifer Powers MD