Authors of section

Author

Tomas Guerrero

Executive Editor

Amy Kapatkin

General Editor

Noel Moens

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Parallel K-wires

1. Principles

In cats, this type of fracture can be treated using internal fixation with parallel K-wires.

Although a lag screw and antirotational pin fixation is preferred for this type of fracture, screw fixation is not always possible in cats and parallel K-wire can provide satisfactory fixation.

31 B1

2. Patient positioning

This procedure is performed with the patient in lateral recumbency.

combined treatment options

3. Approach

A craniolateral approach is performed. If further visualization is needed for fracture reduction, it is combined with a dorsal approach.

craniolateral approach combined with a dorsal approach

4. Surgical technique

Implant selection

Three small K-wires are used to carry out the fracture fixation.

K-wire insertion in the femoral neck

The K-wires are started at a point slightly distal and just cranial to the third trochanter. The wires are directed dorsally and slightly cranially to follow the direction of the femoral neck and avoid the trochanteric fossa.

lag screw fixation

Three K-wires are pre-inserted in the femoral neck. The K-wires are placed parallel to one another with the points visible at the fracture surface.

The wires can be driven in a retro or normograde fashion. Retrograde fashion ensures easier positioning of the pins within the femoral neck but requires a more aggressive exposure of the proximal femur to expose the fracture surface.

The use of an aiming device can also ensure accurate placement.

parallel k wires

Reduction

The fracture is reduced and secured with pointed reduction forceps. The K-wires are driven into the femoral head without penetrating the articular surface.

parallel k wires

The lateral ends of the pins are bent and cut short.

parallel k wires

Validation of fixation

Postoperative orthogonal radiographs are taken to assess fixation.

31 B1

5. Case example

7 year old domestic shorthair cat with a B1 fracture from an unknown trauma.

parallel k wires

The fracture was repaired using 3 parallel K-wires.

parallel k wires

Postoperative radiographs at 1.5 months. One pin backed out after healing of the fracture.

parallel k wires

6. Aftercare

Activity restriction is indicated until radiographs indicate bone healing of the fracture.

Phase 1: 1-3 day after surgery

Aim is to reduce the edema, inflammation and pain.

Integrative medical therapies, anti-inflammatory and analgesic medications.

Note: Nonsteroidal anti-inflammatory medications can be toxic in the cat and should only be used as labeled for the cat.

Phase 2: 4-10 days after surgery

Aim is to resolve the hematoma, edema and control pain, and prevent muscle contracture.

Anti-inflammatory (see nonsteroidal warning) and analgesic medications may still be needed. Rehabilitation and integrative medical therapies can be used.

Special attention should be given to patients less than 1 year of age with a femoral fracture. Rehabilitation is strongly recommended to help prevent quadriceps muscle contracture.

If the cat is not starting to use the limb within few days after surgery, a careful evaluation is recommended.

10-14 days after surgery the sutures are removed.

Radiographic assessment is performed every 4-8 weeks until bone healing is confirmed.

Implant removal

Implants may cause discomfort of the adjacent soft tissue. If this occurs, implants can be removed after bone healing is observed. In case of infection, implants must be removed after healing.

If there is no implant failure or infection, there is no need for implant removal.