Plating is the standard technique for treating forearm fractures in adults and is therefore best considered for skeletally mature or nearly mature children.
Children with open physes have thick active periosteum favoring stability and rapid healing with the ESIN method. Where such techniques are unavailable plating may be used in younger children.
In Monteggia lesions two points are crucial for successful reduction of the radial head:
Restoration of ulnar length
Stable reduction of the radiocapitellar joint
An anatomical reduction of the ulna may not be sufficient to anatomically reduce and stabilize the radiocapitellar joint. An overcorrection of the ulna may be necessary, and this can make plating technically difficult.
Order of reduction and fixation
The usual strategy to deal with a Monteggia lesion is:
Stable anatomical reduction or overcorrection of the ulna
Assess the radial head position and stability using image intensification.
If necessary, revise the position of the ulna.
If necessary, perform an open reduction of the radial head.
Choice of approach
The ulna is exposed by the direct approach between the flexor and extensor muscle compartments.
If the radiocapitellar relationship is not perfect and stable, then the radiocapitellar joint can be explored.
Overcorrecting the ulna can be necessary to improve the stability of the radiocapitellar joint.
The ulnar shaft will hold the radius reduced through the interosseous membrane.
In children with Monteggia lesions and proximal ulnar shaft fractures, a plate can be contoured to produce an overcorrected position.
This may result in greater stability of the radiocapitellar joint than anatomically reducing the ulna.
Ulnar osteotomy for plastic deformity
A Monteggia lesion with plastic deformity of the ulna has a strong tendency for the radial head to redislocate as the ulna rebounds to the original position.
An osteotomy of the proximal ulnar shaft with overreduction can be held with an appropriately contoured plate.
In the illustrated example an apex dorsal angulation of the ulna prevents anterior redislocation of the radial head.
5. Assessing the radial head position
Reduction of radial head
The radial head will usually reduce closed and remain stable once the ulna has been aligned.
Rotational movements 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.
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 stable anatomical reduction of the radial head.
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 of this joint should be performed.
6. Open reduction of radial head
Approach to radial head
Perform a lateral approach and manually reduce the radial head.
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.
7. Final assessment
Check the completed osteosynthesis with image intensification. These images should be retained for documentation or alternatively 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.
Stabilize the elbow at the epicondyles and check the forearm rotation.
8. Aftercare following plating
Immediate postoperative care
Whilst the child remains in bed, the forearm should be elevated on pillows to reduce swelling and pain.
Casting or Splinting
Plate fixation of forearm fractures is intrinsically stable and supplementary casting or splinting is therefore not required.
Some surgeons prefer a long or short splint for 2-3 weeks postoperatively for comfort.
For Monteggia lesions treated with ulnar plating, the forearm may be immobilized in a cast in the position of maximum stability of the radial head for 2-4 weeks.
Ibuprofen and paracetamol should be administered regularly during the first 4-5 days of injury, with additional oral narcotic medication for breakthrough pain.
If the level of pain is increasing the child should be examined.
The child should be examined regularly, to ensure finger range of motion is comfortable and adequate.
Neurological and vascular examination should also be performed.
Compartment syndrome should be considered in the presence of increasing pain, especially pain on passive stretching of muscles, decreasing range of active finger motion or deteriorating neurovascular signs, which are a late phenomenon.