In preparation for surgery, the hair is removed from the distal limb starting from the hoof wall and extending proximally to the mid-metatarsal/metacarpal region. The periopal and superficial hoof wall are removed with a rasp or another suitable instrument such as a electric sanding tool (here shown in lateral recumbency, which is normally not done).
The sole is carefully trimmed and all crevices removed.
2. Preparation for screw insertion - locating the drill holes
In situations, where a screw will be inserted across the fracture and no intraoperative fluoroscopy, 3D-fluoroscopy, or computed tomography is available, the location for the drill hole through the hoof wall is marked preoperatively. For that purpose 4 to 5 radiodense markers, such as lead beets, washers, or thumb tacks (see left side) are taped over the hoof wall in the region where the hole(s) across the hoof wall will be drilled.
The foot is placed on a block of wood and an exact lateromedial radiograph is taken. It may take several slightly different views to arrive at the optimal projection angle.
On the selected lateromedial radiographic view the ideal position(s) of the screw(s) to be implanted is(are) determined and marked on the radiograph.
Left a case of a distal phalangeal fracture.
For fractures of the distal sesamoid bone, the ideal position of the screw to be implanted is determined on the selected exact lateromedial radiographic view. It can then be marked on the radiograph.
The spot selected is subsequently transferred onto the hoof wall using the radiodense markers as aids. The entry point is marked with a 2 mm diameter drill hole of 2 mm depth on the hoof wall.
Left an example for a distal phalangeal fracture.
Example for a fracture of the distal sesamoid.
3. Preparation for aseptic surgery
The entire distal limb and the hoof wall are now prepared for aseptic surgery, ideally not with an iodine-containing antiseptic soap and solution because of the radiodensity of the products, and placed in a sterile bandage. To prevent contamination during the night, a rubber gloves is applied first over the hoof wall itself and another one over the bandage padding prior to wrapping it with a thick layer of elastic adhesive tape. Additional coverage can be applied if deemed necessary.
The horse is placed in lateral recumbency with the affected limb uppermost.
Some surgeons use a tourniquet to prevent intraoperative bleeding (the authors do not apply it). Left, an Esmarch bandage was applied to the distal limb.
The distal limb and the entire foot are scrubbed again for aseptic surgery and draped. The hoof wall is best draped with a sterile adhesive drape such as an Ioban® drape to facilitate good visual control of the surgical site.