1 General considerations top
Definitive nonoperative treatment with a cast is only exceptionally indicated for distal tibia fractures. Nonoperative treatment may, however, be adequate for stable, minimally displaced fractures. Exceptionally, high surgical risk may be an indication for nonoperative treatment in spite of incomplete reduction. Cast immobilization may occasionally be used for initial management until soft tissues recover for ORIF. In highly unstable fractures, a cast may not provide adequate reduction and stability. These fractures should be stabilized with an external fixator.
Always confirm presence of posterior tibial and dorsalis pedis pulses. Check for skin integrity.
2 Indications topenlarge
Split cast as initial temporary treatment
- Simple fractures without displacement and without soft-tissue damage
- As initial treatment until soft-tissue swelling decreases, or for patient transport
- Open fractures
- Fractures with severe soft-tissue compromise (caution: Swelling can increase significantly in the first hours after injury!
- Fractures with compromise of neurovascular structures
- Significant deformity after reduction attempts
- Temporary reduction and immobilization of the fracture
- Allows further imaging (eg, CT) to plan definitive treatment
- May be satisfactory for transfer to care elsewhere
- Limited stability
- Soft-tissue evaluation is difficult
- Risk of compartment syndrome
Temporary joint-bridging external fixation provides higher stability and allows better evaluation of the soft tissues. Therefore external fixation is usually the procedure of first choice for initial fracture reduction and immobilization.
3 Reduction topenlarge
In undisplaced fractures reduction is not necessary. Displaced fractures should be reduced as soon as possible with anesthesia as necessary. The lower leg should be positioned on a pillow so that the heel is slightly elevated from the table.
Hold the foot around its middle from plantar and medial. Grasp the heel with the other hand. Reduction is achieved by gentle traction and by alignment of the foot to match the axis of the lower leg, also correcting rotation.
After reduction, reconfirm presence of palpable pedal pulses.
4 Cast application topenlarge
Once the fracture has been reduced satisfactorily, reduction must be maintained during cast application by gentle manual and/or gravity traction.
Apply abundant cast padding. This should not be too tight, but may include very gentle compression.
Progressive local soft-tissue swelling must be expected during the first days after injury. Therefore, a closed circular cast is usually contraindicated. The cast may be split and spread anteriorly, or “bivalved” with medial and lateral cuts. Make sure that the splitting provides room for swelling, that the padding is not too tight, and that all bony prominences are decompressed.
Plaster of Paris or fiberglass cast tape can be used. With plaster, the cast must be allowed to harden before splitting is possible.
Be aware that a compartment syndrome can occur even after a cast is split. Make sure the split cast is sufficiently stable to support the fracture.
Landmarks for cast application and the importance of adequate padding
Proximally, the edge of the cast lies distal to the popliteal fossa. An easy landmark is 3-4 fingerbreadths below the popliteal crease. All toes should be visible dorsally. The common peroneal nerve, superficial to the proximal fibula, may be compressed by the top of a below-knee cast. Adequate padding, and cast molding (posterior flattening and apex anterior angle) help to minimize this risk.
After application of the cast, the fracture alignment should be documented radiologically.