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
The modular external fixator is optimal for temporary use. It is rapidly applied without need for intraoperative x-rays and can be adjusted later.
The joint-bridging modular external fixator for fractures of the malleoli consists of two partial frames, one along the tibia and one medial on the calcaneus or calcaneus and talus.
Details of external fixation are described in the basic technique for application of modular external fixator.
Specific considerations for joint-bridging modular external fixation, the distal tibia and the foot are given below.
Inserting percutaneous instrumentation such as pins or transfixion wires through safe zones reduces the risk of damage to neurovascular structures.
For safe pin placement make use of the safe zones and be familiar with the anatomy of the lower leg and the foot.
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, 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.
For the construction of the partial frame of the foot the following three options are used most frequently:
Reduce the fracture by manipulating the partial frame of the foot and ligamentotaxis. After checking correct reduction with image intensification, fix the reduced position by tightening all clamps.
External fixation of distal tibial fractures is often extended to include the foot, to avoid an equino-varus deformity. Otherwise consider a splint to support the foot and ankle.
Proper pin insertion
To prevent postoperative complications, pin-insertion technique is more important than any pin-care protocol:
Various aftercare protocols to prevent pin tract infection have been established by experts worldwide. Therefore no standard protocol for pin-site care can be stated here. Nevertheless, the following points are recommended:
Pin loosening or pin tract infection
In case of pin/wire loosening or pin tract infection, the following steps need to be taken:
Before changing to a definitive internal fixation an infected pin tract needs to heal. Otherwise infection will result.
The timing and how much weight may be taken through the fracture will be influenced by:
See patient 7-10 days after surgery for a wound check. X-rays are taken to check the reduction.
Once the fracture is deemed to be sufficiently stable for the external fixator to be removed, the surgeon may choose to apply a cast or functional brace before leaving the ankle completely unsupported.
At 3 months, if there are symptoms of lateral instability, either inversion stress x-rays or MRI can be used to investigate lateral ligament integrity.