Authors of section

Authors

Paulo Barbosa, Felix Bonnaire, Kodi Kojima

Executive Editors

Steve Krikler, Chris Colton

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Tension band plate

1. Principles

Indication

With good bone quality, large infrasyndesmotic fragments of the lateral malleolus with a transverse fracture line can be fixed with a well-contoured plate under slight compression, functioning as a tension band.

tension band plate

Tension band principles

The tension band converts tensile forces into compression forces. The following criteria must be fulfilled for a plate to act as a tension band:

  1. The fractured bone must be eccentrically loaded
  2. The plate must be placed on the tension side
  3. The plate must be able to withstand the tensile forces
  4. The bone must be able to withstand the compressive force which results from the conversion of distraction forces by the plate.
  5. There must be a bony buttress opposite to the plate to prevent cyclic bending. The opposite cortex needs to have contact.
tension band plate

2. Patient preparation and approach

The patient may be placed in the following positions:

For this procedure a lateral approach is normally used.

lag screw and neutralization plate

3. Reduction

Do not strip the periosteum other than minimally, on either side of the fracture site, to control anatomical reduction of the fragments.

Reduce and temporarily hold the fracture with small pointed reduction forceps.

tension band plate

4. Plate preparation

Choosing length and contouring the plate

Choose the length of a one-third tubular plate as determined by preoperative planning. At least two screws must find a secure hold in each of the distal and the proximal fragments. Usually a five- or six-hole plate is used.

Before the plate is applied, it must be contoured.

Contouring is best done with the help of an appropriate aluminum template. The plate should fit the contour of the bone surface perfectly throughout its entire length.

tension band plate

Plate position

Place the contoured plate firmly onto the bone, and determine the position of the first proximal screw near the fracture site.

Remove the plate.

tension band plate

5. Fixation

Plate application

Drill a 2.5 mm hole through both fibular cortices at the planned screw site.

Measure the screw length through the plate, and tap with the 3.5 mm cortical tap in its tap sleeve.

Carefully apply the plate. Insert the first proximal screw. The screw should just penetrate the far cortex.

tension band plate

Insertion of the first distal screw

Next, insert a screw into the first distal plate hole. All distal screws are aimed towards the articular surface of the lateral malleolus. Ensure that their tips do not protrude into the joint by aiming the drill slightly posteriorly.

Carefully predrill an eccentric hole (at the distal edge of the plate hole) until the drill bit just penetrates the far cortex. Measure the length and select a cortex screw approximately 2 mm shorter. Tap threads only into the near fibular cortex and then insert the screw.

Note
In osteopenic bone, fully threaded cancellous bone screws can be used in the distal fragment.

tension band plate

Completing screw insertion

Insert the remaining screws as described above in the sequence of the preoperative plan.

The most distal screw is inserted slightly obliquely, from distal to proximal, in a posterior direction. Again, choose the screw 2 mm shorter than measured and tap the threads only in the near cortical bone.

Gently tighten all screws.

Check under image intensification in both planes to ensure that no screw protrudes into the ankle joint or the syndesmosis.

infrasyndesmotic lateral isolated fracture

6. Pearl

A one-third tubular plate molded as a hook plate can be used to fix a small lateral fragment (where there is space for only one screw), or a severely osteoporotic bone.

The sequence of the application of the hook plate differs from the procedure described above.

First, place the tip of the hook through the ligament into the tip of the lateral malleolus.

Use an impactor for anchoring the hook tip in the bone.

Insert a screw into the hole immediately above the hook to secure the plate onto the distal fragment.

Insert a proximal cortical screw in an eccentric position to obtain compression.

Complete the fixation by inserting the other screws in the planned sequence.

tension band plate

7. Postoperative treatment of infra- and trans-syndesmotic malleolar fractures

A bulky compression dressing and a lower leg backslab, or a splint, are applied, and the limb is kept elevated for the first 24 hours or so, in order to avoid swelling and to decrease pain.

In anatomically reconstructed, stable malleolar fractures, early active exercises and light partial weight bearing are encouraged after day one. In osteoporotic bone, weight bearing should be postponed.

X-ray evaluation is made after 1 week and then monthly until full healing has occurred. Progressive weight bearing is recommended as tolerated.