Authors of section

Author

Tomas Guerrero

Executive Editor

Amy Kapatkin

General Editor

Noel Moens

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Plate and lag screw fixation

1. Principles

Reducible C3 fractures should be anatomically reduced with lag screws and cerclage wires to reconstruct the bone column. K-Wires may be used to provide temporary or additional fragment stabilization.

A plate is used in a neutralization fashion and a lag screw is positioned into the femoral neck and head.

In some situations, it is beneficial to re-attach the femoral head and neck to the proximal fragment before securing the bone plate. This can be done by using an independent screw in lag fashion into the neck. The placement of the plate will have to be slightly modified to not interfere with the screw head.

Note: If anatomical reconstruction cannot be accomplished, the fracture will be indirectly reduced and stabilized with a bridging plate.

Read more about lag screw fixation.

plate and lag screw fixation

2. Patient positioning

This procedure is performed with the patient in lateral recumbency.

combined treatment options

3. Approach

A craniolateral approach is performed in combination with the lateral approach to the femoral shaft.

The length of the incision will depend on the extension of the fracture.

plate and lag screw fixation

4. Surgical technique

Reduction

Main fragments are reduced with the help of bone holding forceps, starting from proximal to distal.

plate and lag screw fixation

Preliminary fixation

K-wires or bone holding forceps may be used to provide temporary stabilization.

plate and lag screw fixation

Fixation of the fragments

The fragments are secured with lag screws and K-wires.

plate and lag screw fixation

Plate selection

The plate is perfectly contoured over the lateral aspect of the greater trochanter.

Note: the plate bending is difficult and needs to be well preplanned. Make sure that one screw hole is positioned to allow screw placement up to femoral head and neck.

Read more about plate preparation.

plate and lag screw fixation

Plate placement

The plate is positioned as proximal as possible to have access to more bone stock for plate fixation.

plate and lag screw fixation

Plate application

Following contouring, the plate is applied to the lateral surface of the reconstructed bone.

The plate position and contouring to the bone is checked thoroughly and adjusted, if required.

plate and lag screw fixation

An antirotational K-wire or screw is inserted in the femoral neck and head.

plate and lag screw fixation

Plate fixation

The plate is fixed in a neutralization fashion. A screw is inserted obliquely in the plate hole that was positioned specifically to engage the femoral neck and head.

The largest diameter screw that will fit the plate should be used for that purpose.

plate and lag screw fixation

A second screw is inserted on the distal part of the bone.

plate and lag screw fixation

Additional screws may be inserted through the plate holes where needed.

plate and lag screw fixation

Validation of fixation

Postoperative orthogonal radiographs are taken to assess fixation.

plate and lag screw fixation

Fixation with a locking plate

If a locking plate is used, only 2-3 locking bicortical screws per main fragment are needed. A lag screw is positioned into the femoral neck and head. One advantage of using a locking plate is that precise contouring is not necessary.

Note: If a combination of cortex and locking screws is used, the plate must be anatomically contoured at the sites of cortex screw insertion. The cortex screws must be inserted and tightened before any locking screws are placed.

plate and lag screw fixation

5. 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.