Open Reduction and Internal Fixation of Monteggia Fractures in Adults

DEFINITION

This injury was initially reported by Giovanni Monteggia in 1814 as a fracture of the ulna associated with an anterior dislocation of the radial head.⁶
The term “Monteggia lesions” was coined by Bado to describe any fracture of the ulna associated with a dislocation of the radiocapitellar joint.¹
The Bado classification of Monteggia lesions,¹ with the Jupiter subclassification of type II fractures,⁴ is shown in Table 1.
Equivalent injuries in adults
- Variable pathology that is thought to be equivalent to injuries classified by the Bado system
- Equivalent injuries do not always fall within the traditional definition of a Monteggia fracture in that they do not always have a concomitant radiocapitellar dislocation.
  
  Therefore, it can be argued that these injuries are not necessarily equivalent to Monteggia fractures.
- Type I and II injuries are the only ones that have equivalent injury patterns.

PATHOGENESIS

The exact mechanism of injury for Monteggia fractures is controversial.
Proposed mechanisms of injury for type I injuries include the following:
- Direct blow to the posterior aspect of the elbow
- Fall on outstretched arm with hyperpronated hand (forearm pronation levers radial head anteriorly)
- Fall on outstretched arm
- Violent contraction of biceps pulling radial head anteriorly
Proposed mechanism for type II injuries: hypothesized to occur when a supination force tensions the ligaments that are stronger than bone
Proposed mechanism for type III injuries: direct blow to the inside of the elbow with or without rotation

PATIENT HISTORY AND PHYSICAL FINDINGS

The initial examination should systematically evaluate:
- Skin integrity
- Neurovascular status of the extremity
- Bony injury
Ulna fracture
- Injury pattern
  - Noncomminuted
  - Comminution
  - Associated injury to key structural elements of the ulna (coronoid, olecranon)
Radial head injury
- Isolated dislocation without fracture
- Radial head or neck fracture

IMAGING AND OTHER DIAGNOSTIC STUDIES

Plain radiographs (FIG 1): Orthogonal radiographs of the elbow, forearm, and wrist are required.
- Ulna fracture is easily identified.
- Radial head fracture or dislocation can be subtle, especially if radial head dislocation reduces.
Computed tomography (CT) scans can be helpful to determine the extent of the bony injury and the location of fracture fragments. They are particularly helpful in fractures involving the coronoid, olecranon, and radial head.
3D CT reconstructions provide information on the spatial relationship of fracture fragments in comminuted fractures.

NONOPERATIVE MANAGEMENT

Monteggia fracture-dislocations in the adult population are generally treated surgically.
Improved fixation methods and surgical technique have remarkably improved the results of surgery, making it a more reliable treatment option.

SURGICAL MANAGEMENT

Preoperative Planning

The timing of surgery depends on the condition of the soft tissues and the availability of necessary equipment and personnel.
The surgeon should define all injuries that need to be addressed.
Equipment requirements:
- Small fragment plates and screws or anatomic plating system
- Minifragment system
- Threaded Kirchner wires
- Radial head replacement
Bone graft (allograft or autograft)

Patient Positioning

Lateral decubitus position with the arm over a padded arm support (FIG 2)
Supine positioning is an alternative approach (although it is not preferred because of difficulty in maintaining the arm across the chest). If this approach is used, a saline bag under the ipsilateral shoulder will help keep the arm across the chest.

Table 1 Bado Classification of Monteggia Lesions, With Jupiter Subclassification of Type II Fractures

Type	Description	Illustration
I	Anterior dislocation of the radial head with fracture of the diaphysis of the ulna with anterior angulation of the ulna fracture (most common type of lesion)
II	Posterior or posterolateral dislocation of the radial head with fracture of the ulnar diaphysis with posterior angulation of the ulna fracture
IIA	Fracture at the level of the trochlear notch (ulna fracture involves the distal part of the olecranon and coronoid)
IIB	Ulna fracture is at the metaphyseal-diaphyseal junction, distal to the coronoid
IIC	Ulna fracture is diaphyseal
IID	Comminuted fractures involving more than one region
III	Lateral or anterolateral dislocation of the radial head with fracture of the ulnar metaphysis
IV	Anterior dislocation of the radial head with a fracture of the proximal third of the radius and ulna at the same level
Adapted from Bado J. The Monteggia lesion. Clin Orthop Relat Res 1967;50:717; and Jupiter JB, Leibovic SJ, Ribbans W, et al. The posterior Monteggia lesion. J Orthop Trauma 1991;5:395-402.