Executive Editor: Peter Trafton, Michael Baumgaertner

Authors: Martin Hessmann, Sean Nork, Christoph Sommer, Bruce Twaddle

Distal tibia Extraarticular, simple fracture

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Glossary

1 Principles of joint-bridging triangular external fixation top

Joint-bridging triangular external fixation in the distal tibia enlarge

A joint-bridging triangular external fixator consists of a Steinmann pin running through the calcaneal tuberosity. A rod is fixed to each end of the pin and connected to the partial frame on the tibial crest.

This triangular frame is extended into the foot to stabilize soft tissues, to fix the foot in a neutral position and to reduce the risk of secondary equinus deformity.

A joint-bridging frame is usually used for temporary stabilization but may be used for definitive treatment if necessary.

Details of external fixation are described in the basic technique for application of modular external fixator.

Specific considerations for joint-bridging triangular fixation and the distal tibia are given below.

2 Pin insertion (tibial shaft) top

Safe zones in the tibia for pin placement enlarge

Pin placement

For safe pin placement make use of the safe zones and be familiar with the anatomy of the lower leg and the foot.


Tibial pin placement enlarge

Choice of tibial pin placement

Drilling a hole in the thick tibial crest may be associated with excessive heat generation and there is a risk the drill bit may slip medially or laterally damaging the soft tissues. As the anteromedial tibial wall provides adequate thickness for the placement of pins, this trajectory is preferable. A trajectory angle (relative to the sagittal plane) of 20-60° for the proximal fragment and of 30-90° for the distal fragment is recommended.


Alternative tibial pin placement enlarge

Alternatively, to avoid the frame catching on the opposite leg, the pins may be placed more anteriorly. The drill bit is started with the tip just medial to the anterior crest, and with the drill bit perpendicular to the anteromedial surface (A). As the drill bit starts to penetrate the surface, the drill is gradually moved more anteriorly until the drill bit is in the desired plane (B). This should prevent the tip from sliding down the medial or lateral surface.

3 Frame construction (triangular external fixation) top

Tibial frame construction for triangular external fixation enlarge

Construction of tibial frame and insertion of Steinmann pin

Insert two pins in the sagittal plane and slightly medial to the anterior tibial crest at an adequate distance above the fracture zone. Connect them with a short rod and tighten the rod-to-pin clamps. Placement more proximally gives room for later definitive open fixation and avoids damaged soft tissue in the fracture zone. Place the pins far enough apart to ensure adequate stability.

Then insert a Steinmann pin, or a threaded pin, from medial to lateral through the calcaneal tuberosity. Take care to avoid damage to the posterior tibial neurovascular bundle.


Tibiocalcaneal frame construction for triangular external fixation enlarge

Tibiocalcaneal connection

Connect each end of the calcaneal pin to one of the tibial pins with a rod using rod-to-pin clamps applied loosely enough to allow reduction of the fracture. 

4 Reduction and fixation (triangular external fixation) top

Tibial fracture reduction with triangular external fixation enlarge

Reduction by manipulating the calcaneal pin

Reduce the fracture by manipulating the calcaneal pin. After checking correct reduction with image intensification, fix the reduced position by tightening all clamps.


Rod connection for stabilization of tibial triangular external fixation enlarge

Connecting the rods

To stabilize the construct, the two tibiocalcaneal rods may be connected with a short rod using rod-to-rod clamps.

Pearl: A bent Steinmann pin can be used as an alternative to a straight rod if needed.


Tibiotarsal transfixation in triangular external fixation enlarge

Tibiotarsal transfixation

To keep the midfoot in a neutral position, one or two small pins should be inserted

  • In one of the cuneiforms or cuboid
  • In the first metatarsal or
  • In the first and in the fifth metatarsal

and connected directly, or through a partial frame, with the tibial frame.


Fixation of a fibular fracture

Fixation of an associated fibular fracture adds stability and contributes to overall reconstruction. However, the possibility of additional soft-tissue injury must be considered before undertaking this step.


Alternative construct for tibial triangular external fixation enlarge

Alternative: Construct starting with a single tibial pin

To achieve a similar triangular construct, it is possible to start with one pin in the proximal third of the tibial crest instead of a partial frame.

Frame construction / reduction and fixation include the following steps:

 

  • Insertion of the tibial pin
  • Insertion of the calcaneal Steinmann pin
  • Connecting the two pins medially and laterally with two rods
  • Reduction by manipulating the calcaneal pin and fixation by tightening the clamps
  • Insertion of a stabilizing pin in the tibia proximal to the fracture through a rod-to-pin clamp on the medial rod
  • Tibiotarsal transfixation

v2.0 2018-11-12