Executive Editor: James Hunter General Editor: Fergal Monsell

Authors: Andrew Howard, Peter Schmittenbecher, Theddy Slongo

Pediatric proximal forearm 21u-M/6.1 Monteggia lesion

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Glossary

1 General considerations top

ESIN (Monteggia lesion) enlarge

In Monteggia lesions, reduction and stable fixation of the ulna are required to ensure stable reduction of the radial head. The most important factor is restoration of the length of the ulna.

The radial head often spontaneously reduces once the ulna is out to length.

If, after assessment of the fixation, the radial head is not accurately aligned to the center of the capitellum in the AP and lateral views, consider overcorrection of the ulna (see illustration).

2 Order of reduction and fixation top

The usual strategy to deal with a Monteggia lesion is:

  1. Stable anatomical reduction or overcorrection of the ulna
  2. Assess the radial head position and stability using image intensification.
  3. If necessary, revise the position of the ulna.
  4. If necessary, perform an open reduction of the radial head.

3 Patient preparation top

Patient preparation enlarge

This procedure is normally performed with the patient in a supine position.

4 Entry point top

ESIN - Entry point to the ulna enlarge

In the ulna use the distal medial entry point.

5 Reduction and fixation of the ulnar fracture top

The alignment of the ulna is addressed first.

The ulna needs to be fully out to length and stable. If this is not achieved, the radial head can redislocate or sublux leading to permanent loss of forearm function.

The steps for ulnar fracture fixation are described in the ESIN procedure (retrograde nail insertion).

6 Assessing the radial head position top

ESIN (Monteggia lesion) - Assessing radial head position enlarge

Reduction of radial head

The radial head will often reduce closed and remain stable once the ulna has been aligned.

Rotation of the forearm may be necessary to complete the reduction of the radial head.

After fixation of the ulna, use an image intensifier to carefully evaluate the position of the radial head relative to the capitellum.

This must be confirmed through a full range of flexion, extension, pronation and supination.

An arthrogram may be helpful, particularly in younger children with an unossified proximal radius.


ESIN (Monteggia lesion) - Revision of ulnar reduction and fixation enlarge

Revision of ulnar reduction and fixation

At this stage the ulnar reduction can be revised if required, often to an overcorrected position, which usually results in a stable anatomic reduction of the radial head.

This can be achieved by overbending and reinserting the ulnar nail. An external fixator or a plate can produce further overcorrection if needed.


Monteggia lesion with a plastic deformity of the ulna enlarge

Ulnar osteotomy for plastic deformity

There is a strong tendency for the radial head to redislocate in a Monteggia lesion with plastic deformity of the ulna.

This is due to rebound of the ulna. Correction of the ulnar deformity with a precontoured elastic nail is recommended. If this is not successful, an osteotomy of the ulna should be considered.

Both of these maneuvers should be performed before considering open reduction of the radial head.


ESIN (Monteggia lesion) - Ulnar osteotomy for plastic deformity enlarge

Osteotomy

Complete reduction with the nail may not be possible in the following cases:

  • Severe bowing
  • Bowing unresponsive to intraoperative correction
  • Narrow nail in a small medullary canal

In this situation, a small osteotome can be used to divide the bone through a small incision over the apex of the bowing.


If there is residual subluxation or instability in any position after optimization of the ulnar correction, there may be interposed tissue (usually annular ligament) in the radiocapitellar joint and an open reduction should be performed.

7 Open reduction of radial head top

ESIN (Monteggia lesion) - Approach to radial head enlarge

Approach to radial head

Perform a lateral approach and manually reduce the radial head.


ESIN (Monteggia lesion) - Removal of blocks to reduction enlarge

Removal of blocks to reduction

The annular ligament is the most common intraarticular block to reduction. In rare cases, the ligament can be gently repositioned around the radial head.

More often the ligament must be incised or excised to allow reduction of the radial head.


Reassessment of radial head position

Reassess the position and stability of the radial head by direct visual inspection and image intensification.

8 Final assessment top

ESIN (Monteggia lesion) - Final radiological assessment enlarge

Check the completed osteosynthesis with image intensification. These images should be retained for documentation.

If an image intensifier is not available, an x-ray should be obtained before discharge.

Make sure that the plate is at the correct location, the screws are of appropriate length, the desired reduction has been achieved and the radial head remains in the appropriate position.

v1.0 2019-08-28