Authors of section

Author

Tomas Guerrero

Executive Editor

Amy Kapatkin

General Editor

Noel Moens

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Plate fixation

1. Principles

The goal with this fracture is to achieve direct bone healing through anatomic reduction and rigid stabilization.

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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.

craniolateral approach combined with a dorsal approach

4. Surgical technique

Plate selection

The plate is perfectly contoured over the lateral aspect of the greater trochanter to allow placement of at least three screws in the proximal fragment.

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 fixation

Reduction

Bone holding forceps are applied to the proximal and distal fragments to allow reduction of the fracture.

plate fixation

Anatomical reduction is carefully checked.

Temporary stabilization can be achieved using temporary K-wires or bone holding forceps.

plate fixation

Plate placement

Weight bearing forces along the mechanical axis cause bending forces on the femur. These bending forces cause tension on the lateral surface of the bone. Tension forces are converted into compressive forces by placing the plate on the lateral surface of the bone.

The plate should be positioned as proximal as possible to maximize the number of screws that can be placed into the short proximal fragment.

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.

plate fixation

Plate application

Following contouring, the plate is applied to the lateral surface of the bone and secured with at least two bone holding forceps.

Note: It is important to use plate holding forceps to ensure the plate does not shift when drilling and placing the screws, causing loss of reduction at the fracture site.

plate fixation

If a locking compression plate is used temporary k-wires through drill guides can be inserted in the proximal and distal fragments instead of bone holding forceps to achieve temporary plate stabilization.

With this temporary fixation in place, the plate position and anatomical reduction are checked thoroughly, and adjusted if required. Orientation of the plate is critical if a locking screw is used to secure the femoral neck, as the orientation of the screw cannot be altered.

plate fixation

Screw insertion

A screw is inserted after drilling with the neutral or load guide through the plate, on one side of the fracture line. The screw is not fully tightened.

Note: Compression plates must be slightly over bent to produce a 1-2 mm gap between the plate and the bone at the fracture site. This will ensure even compression across the fracture line.

plate fixation

A second screw is inserted after drilling with the load guide on the other side of the fracture. The screws are tightened in an alternating fashion, generating compression across the fracture line.

plate fixation

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

plate fixation

All remaining plate screws are inserted in a neutral mode.

plate fixation

Validation of fixation

Postoperative orthogonal radiographs are taken to assess fixation.

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Fixation with locking plate

If locking screws are used, perfect positioning of the plate on the bone is required to ensure that the locking screw aligns with the femoral neck axis.

plate 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.