Trauma and injury to the feet of horses is very common because they often encounter foreign objects at pasture. Partially
buried wires, cables or other obstacles lurk in deep grass, mud or below the surface of streams and ponds. Running through
these areas often results in injury. Horses that kick out while in the barn, trailer or stall can lacerate their distal legs
or hooves on metal walls, wood or other unyielding objects. Many important structures can be involved in this type of injury,
and these wounds can present special problems that make treatment difficult and challenging for veterinarians.
Regional antibiotic perfusion for a laceration to the caudal pastern allows the delivery of high levels of antibiotics to
specific areas of the body, which increases the chances of successful healing.
Dr. Andy Parks, recent inductee into the International Podiatry and Veterinary Hall of Fame and surgeon at the University
of Georgia College of Veterinary Medicine, reminds veterinarians that hoof wounds heal in the same four phases as wounds in
different areas of the body.
"The stages of inflammation, debridement, repair and maturation occur in hoof and foot wounds just as they do in other wounds,
though the specific characteristics of the hoof wall can make these various stages harder to identify and follow," Parks says.
This heel bulb laceration in a young horse continues through the coronary band and involves the navicular bursa, resulting
in a poor prognosis.
Correct treatment and monitoring of wound progression, however, is necessary for optimum healing.
Laceration to the palmar/plantar aspect of the pastern and heel bulbs is a commonly occurring event. Damage to the digital
synovial tendon sheath, deep digital flexor tendon, proximal and distal interphalangeal joints, and navicular bursa all can
occur with injuries to this anatomical area. Involvement of any of these structures greatly worsens the prognosis for recovery
and return to function. Therefore the first step in management of hoof or foot wounds in the horse is to perform a thorough
examination of the injury. This examination may require local or regional anesthesia in order to fully access the damage to
deeper structures. Use of a soft flexible wire probe can be helpful in determining extent and direction of penetrating wounds.
Radiographs sometimes are needed to evaluate the underlying bone or collateral cartilage of the hoof. Lavage with a polyionic
saline solution can be helpful in cleaning the area and determining the type and extent of injury. Dirt, debris and severely
damaged tissue should be removed, taking caution to avoid being overzealous or too aggressive in such debridement. Removing
too much tissue might damage sensitive deeper structures and actually slow wound healing.
This severe incomplete hoof wall avulsion is an example of how the hoof wall can fracture with trauma. The hoof wall fragment
remains attached along one side. Many deeper structures can be involved, including the collateral cartilage, deep digital
flexor tendon and distal interphalangeal joint. A complete examination, including joint lavage, will be necessary to assess
the extent of the damage and the prognosis.
Mild antibiotic solutions may be used to flush and clean the wound, but Parks cautions against using strong products, such
as iodine scrubs and solutions because iodine itself can coagulate protein and damage deeper tissue in the hoof. Parks advocates
the use of no stronger than 0.1 percent to 1 percent povidone iodine or 0.05 percent chlorhexadine solutions. The evaluation
of synovial structures and tendon sheathes requires the infusion of sterile saline solution at a point far removed from the
trauma. If the saline solution is noted to be leaking from the wound, then the joint or tendon sheath has been compromised
and should be considered infected. If the infused saline is not seen leaking from the original injury, then no damage to the
joint or tendon sheath is suspected.