Monteggia Fracture - Pediatric - Pediatrics

Introduction

Definition
- radial head dislocation plus
- proximal ulna fracture or
- plastic deformation of the ulna without obvious fracture
Epidemiology
- 4 to 10 years of age is peak incidence
Treatment differs from adult Monteggia fractures

Classification

Bado Classification
Type I	Apex anterior proximal ulna fracture with anterior dislocation of the radial head
Type II	Apex posterior proximal ulna fracture with posterior dislocation of the radial head
Type III	Apex lateral proximal ulna fracture with lateral dislocation of the radial head
Type IV	Fractures of both the radius and ulna at the same level with an anterior dislocation of the radial head (1-11% of cases)

Presentation

Symptoms
- pain, swelling, and deformity about the forearm and elbow
Physical exam
- must palpate over radial head with all ulna fractures because spontaneous relocation of radial head is common
- must examine for plastic deformation of the ulna if there is a presumed isolated radial head dislocation
  - isolated radial head dislocations almost never occur in pediatric patients

Imaging

Radiographs
- obtain elbow radiographs for all forearm fractures to evaluate for radial head dislocation
  - assess radiocapitellar line on every lateral radiograph of the elbow
    - a line down the radial shaft should pass through the center of the capitellar ossification center
- obtain forearm radiographs for all radial head dislocations

Treatment

Nonoperative
- closed reduction of ulna and radial head dislocation and long arm casting
  - indications
    - Bado Types I-III with
      - radial head is stable following reduction
      - length stable ulnar fracture pattern
  - reduction technique
    - reduction technique uses traction
      - radial head will reduce spontaneously with reduction of the ulna and restoration of ulnar length
      - for Type I, elbow flexion is the main reduction maneuver
  - immobilization
    - Type I 110° of flexion and full supination to tighten interosseous membrane and relax biceps tendon
    - Type II fulll extension.
    - Type III full extension and valgus mold
Operative
- plating of ulna + reduction of radial head ± annular ligament repair/reconstruction
  - indications
    - Bado Types I-III with
      - radial head is not stable following reduction
      - ulnar length is not stable (unable to maintain ulnar length)
    - acute Bado Type IV
    - open fractures
    - older patients ≥ 10y if closed reduction is not stable
  - technique
    - annular ligament reconstruction almost never required for acute fractures
    - open reduction of radial head through a lateral approach if needed in chronic (>2-3 weeks old) Monteggia fractures where radial head still retains concave structure
    - symptomatic individuals (pain, loss of forearm motion, progressive valgus deformity) who had delayed treatment or missed diagnosis
- ORIF similar to adult treatment
  - indications
    - closed physes

Complications

Neurovascular
- posterior interosseous nerve neurapraxia (10% of acute injuries)
  - almost always spontaneously resolves
Delayed or missed diagnosis
- common when evaluation not performed by an orthopaedic surgeon
- complication rates and severity increase if diagnosis delayed >2-3 weeks