Rigid Flatfoot Deformities: Flatfoot Reconstruction With a Subtalar Fusion Using Screws

Rigid Flatfoot Deformities: Flatfoot Reconstruction With a Subtalar Fusion Using Screws

This video will provide a demonstration of a subtalar fusion with the use of compression screws on a cadaveric specimen for the treatment of a rigid flatfoot deformity. In review, joint fusion procedures are often required for rigid flatfoot deformities that have progressed to include deformity or collapse of the back of the foot. A fusion of the joint between the talus and the calcaneus may be indicated in this condition, also known as a subtalar fusion.

The surgeon will start by marking out the placement of the incision to the outside of the left foot. An incision will be made overlying the subtalar joint. Once the soft tissues are exposed, a retractor will hold open the surgical field. The surgeon identifies several important structures in this area: the peroneal tendons, the sural nerve, and the C F L, or calcaneofibular ligament. The surgeon will carefully protect these structures during the surgery.

The surgeon will use an instrument to distract or pull the subtalar joint open to prepare the joint for fusion. This allows the surgeon optimal viewing of the joint. The surgeon will use a tool to remove the thin, protective layer of cartilage from the bone ends. The cartilage must be removed for the joint to fuse. This is the joint after the cartilage has been removed.

The first of 3 wires will be placed as a guide for the incoming compression screws. The first wire is shown already placed across the joint. The surgeon is now placing a second wire. This x-ray shows the 2 wires across the joint. Multiple x-rays will be taken from different angles to confirm their placement. And finally, a third wire will be placed in a new plane to provide further support.

A depth gauge will be placed over the first wire to measure the length of the first screw. Then a specialized drill bit, called a profile drill, will be used to make the initial path in the bone for the incoming screw. The profile drill will be removed, and a drill bit will be used over the wire to create the full path for the screw. X-rays will continue to be used to verify the safe placement of the instruments.

The drill bit will be removed, and the initial wire will remain in place. A cannulated or hollow-bodied compression screw will be placed over the wire and placed across the joint, first with a power drill, then completed with a hand driver. An x-ray will be done to check placement. The exact process will be completed for the next screw. Here, the 2 screws are shown. For the final wire, the process will be completed with a smaller size screw. The final x-ray shows all 3 screws in place. The incision will now be closed, and the surgery is complete.