Saturday, July 30, 2011

Transsyndesmotic fibular fracture, with medial lesion Simple, with fracture of the medial malleolus


Fracture of the fibula
    A simple, oblique fracture occurs at the level of the syndesmotic ligaments, and is displaced.
Medial lesion
    Transverse, or oblique, fracture of the medial malleolus.
Anterior syndesmosis
    A ligamentous rupture, or avulsion fracture, of the anterior syndesmotic ligament, either at its fibular (Le Fort / Wagstaff), or tibial (Tillaux-Chaput) insertion.

Operative treatment

Preparation

   The patient is positioned supine on a radiolucent table with a sandbag under the ipsilateral buttock and with the knee slightly flexed.

Approach

   The lateral incision is the standard approach for most fibular fractures.
Fixation
   Lateral bridging plate

Reduction

   In multifragmentary fractures, care must be taken to avoid excessive stripping of the periosteum as well as devascularization of the fragments.
  Indirect reduction usually is obtained by longitudinal traction, either on the foot, or of the main distal fragment using a bone hook.
If the distal fragment is large enough, insert one or two K-wires to hold the reduction.
The correct length, rotation and alignment must be checked under image intensification.

Plate preparation

Contouring the plate

   Choose the length of the one-third tubular plate as determined by the preoperative plan, so that at least two screws find a secure hold in each of the distal and the proximal fragments. Usually a six-hole plate is used.
Before the plate is applied, it must be contoured.
Contouring is best done with the help of the appropriate aluminum template. The plate should perfectly fit the bone contour throughout its entire length.

Plate position

   Position the plate firmly by hand and plan the position of the first proximal screw near the fracture.
Remove the plate.

Fixation

Insertion of first proximal screw

   Drill a 2.5 mm hole through both fibular cortices at the planned screw site, 3 mm proximal to the fracture.
Measure the length through the plate, tap with the cortical tap and tap sleeve.
Carefully apply the plate. Insert the first proximal screw.
The screw should just penetrate the far cortex.

Insertion of 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.
Predrill carefully until just reaching the far cortex. Measure the length and select a 3.5 mm cortex screw approximately 2 mm shorter. Tap threads only in the near fibular cortex, and insert the selected screw.
In osteopenic bone, fully threaded cancellous screws can be used.

Completing screw insertion

   Insert the remaining screws as described above in the sequence determined by the preoperative plan.
The most distal screw is inserted slightly obliquely from distal to proximal  in a posterior direction.
Again choose a screw 2 mm shorter than was measured and tap the threads only in the near cortex.
Gently tighten all screws.
Check under image intensification in both planes and ensure that no screw protrudes into the ankle joint or the syndesmosis.
After fixation of the lateral malleolar fracture, reduce and fix the medial malleolus. Consider fixation with lag screws or tension band wiring.

Fixation with tension band wiring

Insert the first K-wire

   Drill a 1.6 mm K-wire through the posterior colliculum as perpendicularly as possible to the fracture plane.
Take special care not to cross the fracture line too closely to the joint.

Avoid penetration of the ankle joint, or the lateral tibial cortex.

Insert a second K-wire

   A second 1.6 mm K-wire is inserted into the anterior colliculum of the medial malleolus, parallel to the first wire.
These two K-wires stabilize the fracture against rotation and will be used to anchor the figure-of-eight wire distally.
Check the reduction under image intensification.
Care must be taken to avoid intraarticular positioning of the K-wires.

Wire insertion

   Drill a 2.5 mm hole, with the protection of a drill sleeveinto the tibia
Insert the wire.

Wire application

   Prepare the 0.8 -1.0 mm wire by making a loop at approximately one third along its length.
Pass the shorter segment of the wire close to the bone around the two K-wires.
Pass the longer segment of the wire (bearing the loop) around the screw between bone and washer, forming a figure-of-eight.
Twist the free ends together.

Wire tigthening

   The wire twist is loosely prepared ensuring that each end of the wire spirals equally - the twist should not comprise one spiral around a straight wire.
The wire is tensioned by pulling on the twists.
The slack is then taken up by further twisting. Repeat this until the desired tension is achieved. Both loops must be tightened at the same time and in the same direction, in order to achieve equal tension on both arms of the wire.
Tighten the screw carefully. Trim the twisted wire and turn both ends towards the tibia in order not to irritate the soft tissues later.

In osteopenic bone care must be taken to avoid excessive tensioning.

Finishing fixation

   Cut the 2 K-wires obliquely, approximately 1 cm from their insertion points and, with the help of a bending iron and forceps, bend through 180 degrees.
The K-wires are then driven home, sinking their curved ends into the bone in order to prevent backing out and skin injury.
   Take final x-rays in both planes to check the results.