K-wire fixation provides less stability than ESIN fixation. It needs additional cast or splint immobilization to prevent elbow movement during healing causing elbow stiffness. Other potential disadvantages include infection and cross-union.
This treatment may be used for reduction and fixation of a radial head that is severely displaced or if an image intensifier is not available.
2. Instruments and implants
The following equipment is needed:
K-wires of appropriate sizes
Drill or a T-handle for manual insertion
Wire cutting instruments
Standard orthopedic instrument set
3. Patient preparation
This procedure is normally performed with the patient in a supine position.
Protect the remaining periosteum throughout the reduction maneuvers.
Pearl: minimizing additional vascular damage to the radial head
To minimize the risk of additional vascular damage to the radial head the following procedure is recommended:
1. Attempt initial reduction of the fracture through the closed capsule.
2. If unsuccessful, perform a dorsolateral arthrotomy with irrigation of the joint. The displaced radial head can usually be seen, irrespective of the direction of displacement.
3. Digitally reduce the head fragment.
4. If the head is entrapped/displaced in an unusual direction use a dental hook or an identical shaped K-wire push/pull the radial head to an appropriate position.
After anatomical reduction the head fragment, placed between the metaphysis of the radius and the capitellum, is usually stable. Preliminary fixation is therefore not necessary.
General K-wire principles
Use K-wires with a sharp tip.
Powered insertion of K-wires generates heat in the tissues. Insert wires with a slow-running drill or by hand.
If multiple attempts are made to insert any one K-wire the bone may be weakened or the physis may be damaged. In general, only two attempts of insertion of any K-wire are advisable.
Insertion of K-wires
The K-wires must provide adequate spread at the fracture site on any view.
If the K-wire spread is inadequate, the fixation is likely to be rotationally unstable.
Pitfall: The K-wires should engage the far cortex but not protrude into the soft tissues.
Confirm the position of the K-wires on both AP and lateral views.
If the position is inadequate, adjust the K-wires.
Trimming of K-wires
Whether the K-wires are left outside the skin or cut and buried beneath the skin depends on the surgeon’s preference.
K-wires may be left protruding, but there is a risk of pin-track infection. The advantage is that the K-wires can be removed without anesthesia.
Close the wound in layers with resorbable sutures.
Final radiological documentation
Take standard x-rays in lateral and AP view.
7. Additional immobilization
K-wire fixation alone confers minimal stability. Additional immobilization is required to reduce the risk of secondary displacement.
Immobilize the arm in 90° flexion of the elbow with a cast or a splint to prevent elbow movement.
8. Aftercare following K-wire fixation and immobilization
Duration of immobilization
Radial head and neck fractures usually require 3-4 weeks of cast immobilization for adequate callus formation.
Ibuprofen and paracetamol should be administered regularly during the first 24-48 hours after surgery, with opiate analgesia for breakthrough pain.
Opiates should not be necessary after 48 hours and regular ibuprofen and paracetamol should be sufficient until 4-5 after injury or surgery.
The child should be examined if the level of pain is increasing or prolonged analgesia is needed.
The child should be examined after casting/splinting, 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 is a late phenomenon.