Tension band

Avulsion of the greater trochanter can be effectively stabilized using the tension band technique.

The principle of a tension band device is to convert distractive forces generated by the muscle pull into compressive forces across the fracture line.

To take advantage of this resultant force, the pins should be oriented perpendicular to the fracture plane.

This procedure is performed with the patient in lateral recumbency, and through the craniolateral approach.

The fracture or osteotomy is reduced and secured with pointed reduction forceps.

Two K-wires are driven perpendicular to the fracture line and parallel to each other.

Insertion starts at the dorsal ridge of the greater trochanter. The pins are anchored distally in the medial cortex of the femur.

A hole is drilled from the lateral aspect of the femur below the fracture line for anchorage of the wire. A pin or small drill bit can be used for that purpose.

The hole is made below the fracture plane at an equal distance from the point of insertion of the K-wires to the fractures.

The wire is passed through that hole and around the pins creating a figure-of-eight pattern.

A loop is created in the long arm of the wire. The free ends of the wire and the “loop” are alternately tightened, so that both arms of the wire are twisted equally.

It is important for the wire to be in contact with the pins and underneath any muscle or tendon. Placing the wire above the tendon would result in necrosis of the tendon and loosening of the tension band.

The pins are bent to sit close to the bone, and cut short. This avoids soft tissue irritation.

Postoperative orthogonal radiographs are taken to assess fixation.

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

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.

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.

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.