Authors of section

Authors

Fergal Monsell, Dalia Sepulveda

General Editor

Chris Colton

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Open reduction; K-wire fixation

1. Introduction

These fractures are often caused by direct blow. The direction of displacement is determined by the direction of the blow.

open reduction k wire fixation

2. Patient preparation

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

closed reduction short or long arm cast

3. Approach

Ulnar approach

For this procedure an ulnar approach is normally used.

open reduction k wire fixation

Anatomy to the distal forearm

A thorough knowledge of the anatomy of the wrist is essential.

The additional material gives a short introduction.

closed reduction short or long arm cast

4. Reduction

If closed reduction is not possible, this may be due to soft tissue interposition with structures including the ulnar nerve, flexor carpi ulnaris or rarely extensor carpi ulnaris.

Open reduction may be necessary with a direct approach to the subcutaneous surface of the ulna.

Care should be taken to avoid the dorsal sensory branch of the ulnar nerve.

open reduction k wire fixation

Open reduction

For irreducible fractures, initially, any soft tissue structures that are preventing reduction are identified and cleared.

open reduction k wire fixation

Reduction is performed under direct vision.

This may require using a K-wire either as a joystick or as a lever.

Posteriorly displaced fractures are reduced with forearm pronation. Anteriorly displaced fractures are reduced with forearm supination.

open reduction k wire fixation

5. K-wire fixation

A single smooth 1.6 mm K-wire is inserted through a protective sleeve into the ulnar styloid, through the physis, then engaging the lateral cortex of the ulnar diaphysis.

The wire should be inserted with an oscillating drill and cooled with saline solution to prevent thermal injury.

The wire may also be inserted by hand using a T-handle.

open reduction k wire fixation

Ideally, wire insertion is monitored using image intensification in order to check the trajectory of the wire and to ensure engagement of far cortex without penetration of soft tissues.

The K-wire is left protruding through the skin, bent and cut. The skin is protected with sterile padding prior to application of a cast.

The illustration demonstrates the use of a small section of plastic tubing over the cut end of the protruding wire. This adds further protection for the skin.

Note: Excessive pressure should be avoided between dressing and skin to prevent skin necrosis.

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6. Long arm cast

General considerations

Once the fracture displacement has been reduced and fixed with a K-wire, the arm is splinted in a reduced position with a long arm cast to control forearm rotation.

The purpose of the cast is to maintain reduction by preventing forearm rotation and protect the fixation.

The long arm cast is applied according to standard procedure:

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Splitting of the cast

If a complete cast is applied in the acute phase after injury, it should be split over the full length of the cast. The split of the cast must be full thickness and expose the underlying skin.

closed reduction long arm cast

7. Aftercare

Tight cast

Further swelling in a restricting cast can cause pain, venous congestion in the fingers and occasionally a compartment syndrome.

For this reason any complete cast applied in acute phase should be split down to skin.


closed reduction short or long arm cast

Parents/carers should be instructed how to detect circulatory problems by pressing and releasing the fingertips and watching if the blood flow/color returns to normal (capillary refill), compared to the opposite hand.


closed reduction short or long arm cast

Compartment syndrome

Compartment syndrome is an unusual but serious complication after the application of a complete cast and can be difficult to diagnose, especially in younger children. Neurological signs appear late and the main sign is excessive pain on passive extension of the fingers.

It is important to make sure that the parents/carers are aware of the risk of compartment syndrome.


closed reduction short or long arm cast

The parents/carers and patient should be informed to take note of increased pain and/or unresponsiveness to normal painkillers.

They should know that this may indicate serious complications. It is important for them to detect these signs as early as possible and report them urgently to the surgeon/nurse by telephone, or to attend the Emergency Room (ER) without delay.


closed reduction short or long arm cast

Nerve compression is an occasional complication and the signs include:

  • Sensory deficits (numbness)
  • Weakness of active finger movement
  • Paresthesia

Infections

See also the additional material on postoperative infections.

Cast care

If a normal plaster of Paris cast is used, it is important to keep the cast clean and dry in order to maintain the reduction.

When the swelling has reduced, the cast can become loose. The loss of support can result in loss of reduction.

In this circumstance, the parents/carers are advised to return to the healthcare provider.

Follow-up x-rays

Depending on the fracture pattern, the age of the child and the method of treatment, the patient has to return for follow-up x-rays to monitor the fracture position.

X-rays taken for fracture position can be taken with cast in place. Any x-rays to assess the state of bone healing must be taken without the cast and correlated with clinical examination.

In most cases, it is conventional to obtain follow-up x-rays after reduction to ensure that the position is maintained.

In general, in the child below 5 years of age, the follow-up is usually about 4-5 days after reduction. In the older child with a potentially unstable fracture, an x-ray would normally be taken at 7-10 days.

Further follow-up x-ray is a matter of clinical judgement, the responsibility of the treating surgeon, and tends to be longer in older children (see also Healing times).

For complete fractures of the metaphysis, redisplacement after reduction is not uncommon. It is therefore, important to take early follow-up x-rays in order to detect a possible redisplacement.

See also the additional material on posttraumatic growth disturbances.

K-wire removal

The K-wires can be removed without sedation in the clinic after approximately 3 weeks (depending on the age of the child).