K-wires can be applied to many different fracture patterns. Considerations include fracture obliquity, comminution, and soft tissue status.
As K-wires cannot compress the fracture, the fracture needs to be reduced before K-wire insertion, which is particularly true for articular fractures.
The preferred K-wire configuration would be extra-articular to prevent damage to the articular surface. Axially inserted wires that break may be difficult to retrieve.
Threaded K-wires are generally not preferred as they are more challenging to extract and potentially maintain fracture gaps.
Reduction of the proximal phalanx should be anatomic when possible.
The goal of an intramedullary wire would be to secure the fracture site in a soft-tissue-friendly manner while maintaining alignment.
K-wires should be sized appropriately to the bone. Typically, wires thicker than 2.0 mm are not needed. The surgeon should be careful to cool the K-wire during insertion to reduce the risk of thermal necrosis.
Toe fractures versus long bone fractures
Toe fractures are different from long bone fractures.
The bones are very small
Fracture gaps are small
Fixation devices don't need to counter large forces
Thus, following the AO principles is less critical than for long bones, and often isolated screws or K-wires alone will work satisfactorily.
Restoration of length, rotation, and angulation are important for cosmesis.
The hallux is particularly critical due to its importance for walking.
Timing of surgery
The timing of surgery is influenced by the soft tissue injury and the patient's physiologic status.
Dislocation or injuries associated with the skin at risk requires immediate intervention regardless of the amount of soft tissue swelling.
If possible, swelling should be significantly decreased before surgery, which can take up to two weeks in some instances.
Open fractures should be promptly irrigated and debrided, and treated with antibiotics. Definitive fracture fixation may not be possible during this setting.
Forefoot fractures do not contribute to physiologic instability. If there is no soft tissue at risk, urgent intervention is not required.
Depending on the size of the fragment, more than one K-wire will provide stability to the fracture.
Both K-wires can be inserted from the medial side of the bone in a diverging pattern.
Consider inserting the K-wires outside the skin incision to prevent contamination.
3. Reduction and preliminary fixation
Grasp the digit's terminus and use a combination of axial and angular traction to exaggerate the deformity.
Realign the toe and release the traction.
When an anatomic reduction is desired, it is crucial to debride the hematoma and invaginated periosteum from the fracture site.
Restore anatomical axial rotation, length, and angulation using one or more of the techniques below.
A small, pointed reduction forceps can be used for larger fragments. Be careful not to apply excessive force as this can lead to fragmentation. If possible, apply the reduction clamp so that the forces created by the clamp are at right angles to the fracture line. This clamp placement helps in reducing the fracture and in applying compression.
K-wires can be inserted into the fragment and used as a joystick. Once reduction is accomplished, the wire may be advanced to secure the reduction.
Use image intensification to confirm the reduction.
4. K-wire insertion
K-wires are inserted percutaneously according to the preoperative plan (if not already done so using the joystick technique).
Caution should be made to prevent thermal injury when inserting a K-wire in dense bone.
Intraoperative fluoroscopy is particularly useful to aid the correct position of the K-wire.
The stability of the reduction is assessed, and if needed, additional K-wires are inserted.
When satisfactory stability is achieved, cut the K-wire so that it protrudes through the skin, about 1 cm from the tip of the toe.
With the wire placed in a finished position, clamp the portion of the wire nearest the skin with a Kocher.
Using a sucker tip that goes over the tip of the K-wire, the K-wire is bent 170°.
Assess the skin pin interface and release any excessive skin traction.
Leaving the K-wire to protrude through the skin in this way has the advantage of its being easy to remove. The disadvantages are patient discomfort and the risk of pin-track infection.
An appropriate well-padded dressing should be applied to protect the surgical incision.
The skin pin interface should be similarly well-padded but with dressings that can be readily removed to inspect for pin site infection.
Immediate postoperative treatment is rest, ice, and elevation.
The patient should be encouraged to begin early weight-bearing as permitted by the stability of the fracture. In general, patients can be weight-bearing as tolerated.
A stiff-soled shoe can be used to protect the surgical site.
Patients must exercise their ankle and subtalar joints to prevent stiffness (eg, by stretching their Achilles).
X-ray the toe at six weeks to confirm satisfactory union and remove K-wires if present. Once the fracture is united, the orthosis may be gradually discontinued.