Generally, reduction is closed and the implants are placed through stab incisions. If required, a short incision over the fracture site can be performed to aid in reduction. Correct articular reduction can partially be evaluated arthroscopically. Potential small loose articular fragments can be removed under arthroscopic supervision.
In foals the fracture typically extends through the distal medial physis of the tibia and is under tension by the medial collateral ligaments. The use of a transphyseal bridge composed of cortex screws and a 1.25 mm figure-of-8 wire are appropriate for fixation. A single transphyseal bridge is usually sufficient, but multiple bridges or wires may be applied depending on the size of the horse.
3. Reduction and Fixation
The borders of the medial malleolus are identified with radiographic markers (needles or drill bits). Based on the location of the markers, a stab incision is made in the distal fragment.
Placement of the first screw
A 4.5 mm cortex screw through a washer is placed in a distoproximal direction across the fracture site into the parent tibia using lag technique. Care is taken to avoid penetrating the axial border of the medial malleolus and entering the tarsocrural joint. The screw is not completely tightened. No countersink is required.
A second 4.5 mm screw is placed across the medial cortex of the distal tibial metaphysis approximately 70 mm proximal to the distal screw, through a separate stab incision. The screw is not completely tightened. A 20 cm length of 1.25 mm cerclage wire is cut and bent into a figure-of-8 pattern. The wire is passed subcutaneously through the stab incisions using a hemostat and placed around the screw heads. The free ends of the wire should exit the proximal stab incision. The wire ends are tightened, twisted, cut and pressed against the medial tibia. Both screws are subsequently tightened. The stab incisions are closed with one or two single interrupted sutures.
Care should be taken during recovery to prevent disruption of the repair. Use of a splint (arrow) or cast-bandage is recommended to protect the tarsus during recovery. These devices can be removed immediately postoperatively and a bandage can be applied. The horse is confined in a stall for 12 weeks with hand walking in weeks 9-12 followed by pasture turn-out for 4 weeks. Younger animals may require less time of confinement. Radiographic evaluation is recommended at 8-16 weeks. Implant removal is not required, except in growing animals. Implant removal will improve the cosmetic appearance.