1 Note on illustrations topenlarge
Throughout this treatment option illustrations of generic fracture patterns are shown, as four different types:
A) Unreduced fracture
B) Reduced fracture
C) Fracture reduced and fixed provisionally
D) Fracture fixed definitively
2 Principles of modular external fixation topenlarge
The modular external fixator is optimal for temporary use. It is rapidly applied without need for intraoperative x-rays and can be adjusted later.
Details of external fixation are described in the basic technique for application of modular external fixator.
Specific considerations for the tibial shaft are given below.
AO teaching video: Modular external fixator
3 Patient preparation topenlarge
This procedure is normally performed with the patient in a supine position.
4 Safe zones for pin placement topenlarge
For safe pin placement make use of the safe zones and be familiar with the anatomy of the lower leg.
The pin in the distal tibia should be placed far away from the extensor tendons on the medial side.
5 Pin insertion (tibial shaft) topenlarge
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.
Alternatively, in order 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.
6 Frame construction / reduction and fixation (tibial shaft) topenlarge
Reduction and fixation
Restore length with a bolster behind the knee to give slight flexion.
Plating of the fibula
In order to add further stability to the reduction, a fractured fibula may be plated.
Pearl: Prevent plantar flexion contracture
In patients with severe soft-tissue involvement, it may be helpful to add a pin in the foot (one of the tarsal or metatarsal bones) to maintain the ankle at a 90° angle and prevent a plantar flexion contracture.
The pin may be inserted in either the navicular bone, in one of the cuneiforms, in the first metatarsal base, or in the first and fifth metatarsal base, and connected with a rod to the tibial external fixator. Care should be taken to insert the pin bicortically and to avoid the intra-articular spaces.