Foot Abcess
Foot abscesses tend to be painful with the horse reluctant to stand on the foot. The infection may even result in soft-tissue swelling in the lower limb.

Although foot abscess may be signaled by a strong, throbbing pulse in the foot, they are often difficult to locate and require treatment by someone skilled with hoof testers and knife.

abscess.jpg The object of treating a simple subsolar abscess is to open and drain the infection. The opening should be of sufficient size to allow drainage but not so extensive as to create further damage. Establishing drainage is the most important aspect of therapy. Preferably, this is done at the onset of lameness before the infection ruptures at the coronet. The offending tract or fissure is opened on the hoof wall side of the white line using a 2 mm bone curette or other suitable probe. A small opening is sufficient to obtain proper drainage and care must be taken to avoid exposing solar corium, as it will invariably prolapse through the opening and create an ongoing source of pain. The draining tract is kept soft and drainage is enhanced by the application of an Animalintex® poultice for the first 48 hours. This is a self-contained, medicated poultice, which is commercially available through Dr. Garfinkel. In most cases, this eliminates the need for continued foot soaking. The horse should show marked improvement within 24 hourshoof_full.jpg.

The hoof is kept bandaged with a suitable antiseptic such as Betadine® ointment or 2% iodine until all drainage has ceased and the wound is dry. At this point, a small gauze plug is used to fill the opening of the tract and is held in place with super glue. This keeps the affected area clean and prevents the accumulation of debris within the wound. The shoe is replaced when the horse is sound. Many times the painful tract can be located but drainage cannot be established at the white line. In this case, the infection has migrated under the sole away from the white line.

Under no circumstances should an opening be created in the adjacent sole. This only leads to a persistent, non-healing wound and increased susceptibility to bone infection. Instead, a small channel should be made on the hoof wall side of the white line in a vertical direction following the tract to the point where it courses inward. Drainage can be established here in a horizontal plane. Tetanus immunization status of the horse should be determined. Use of systemic antibiotics is optional and based on the needs of the individual horse.

A shoe and pad may help return the horse to work while the wound continues to strengthen.

The tetanus status should always be checked on each puncture patient, since Clostridium tetani, an anaerobic bacterium, can grow in the wounds.

If a horse is found with a nail still in place in the foot, don’t remove it. Call Dr. Garfinkel who can radiograph the foot with the nail in place to determine which structures are involved.

Prevention is achieved through proper hoof care and centers around promoting a strong, solid white line which resists penetration by debris. Excessive toe length increases the bending force exerted on the toe, leading to a widening and weakening of the white line. This, along with toe cracks and hoof wall separations, is the most common cause of foot abscesses.

To prevent abscesses it is important that the foot be trimmed in a manner that accentuates a strong healthy foot. A few basic principles can be used when trimming to create a strong foot and strengthen the white line. First, the bars of the foot are left untouched and the heels are trimmed back toward the widest part of the frog, or as far back as possible. This allows a large amount of weight bearing to occur in the posterior portion of the foot and not the toe area. Sole is only removed adjacent to the white line to identify excess hoof wall to be removed. It is not necessary to concave the sole as this occurs naturally. The toe is then backed up from the dorsal surface (front) of the hoof wall and/ or the breakover is set back accordingly. This assures that there is no excessive toe length. A good rule of thumb to use when trimming the foot is to leave the last few rubs on the bottom of the foot. When applying shoes, fitting the shoes hot may be helpful to seal the sole wall junction. The use of hoof hardeners (Keratix®) and bedding the horse on shavings or sawdust may be useful to harden the feet during extremely wet weather or when the horse is being washed frequently such as during horse shows. During dry weather, a hoof dressing such as a combination of cod liver oil and pine tar (mixed in a ratio of 3:1) painted on the entire foot may help to contain moisture.

Preventing indirect penetration through the white line is therefore dependent on providing adequate protection to the underlying sensitive structures. The hoof capsule has a natural ability to provide such protection and it is imperative that we strive to enhance these strong features through proper trimming. Excessive removal of protective horn is a common practice, as emphasis is often placed on eye appeal instead of functional strength.

If you have any concerns or questions on Foot Abscesses contact us at 619-659-1180.