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Wire Fencing Injuries: Heel Bulb Laceration

10/01/2013 by Dr Craig Simon, BVSc (Hons) GPCert (EqP) MACVSc (EqSurg) CMAVA

Horses frequently get their legs caught up in wire or barbed wire fences, resulting in some horrific injuries. Lacerations to the heel bulb region of the foot are one of the more common injuries seen. Treated correctly, heel bulb lacerations can have excellent functional and cosmetic results. There are, however, some important structures in this region, which can have devastating consequences if damaged.

The signs

Often, the first problem noticed is that the fence has been damaged or pulled down. Frequently, with heel bulb injuries, the horse will be lame. How lame the horse is will depend on how deep the injury is, how old the injury is, what structures are involved and the pain tolerance of the horse. 

There can be an extraordinary amount of haemorrhage apparent, because of the relatively superficial nature of the blood vessels in this area. They are only protected by the skin and a thin layer of fascia, making them very vulnerable to damage. So much blood can be lost that the horse becomes depressed and weak.

Take note of any discharge that is present. If the injury is recent and there is damage to synovial structures, there may be synovial fluid oozing from the wound. More chronic wounds may be infected and, therefore, discharging purulent material with a foul odour. These wounds are often heavily contaminated with mud and dirt from the environment, and hair from the surrounding skin. If the wound is not cleaned adequately or promptly, this can lead to infections and may compromise healing.

First Aid

Stem the bleeding: The relative proximity of the vessels to the skin can lead to substantial blood loss. The bleeding can usually be stopped by applying pressure with a clean towel. Alternatively, a pressure bandage can be applied to the limb and foot.

If possible, move the horse to a safe, well-lit area for examination of the wound. Take steps to calm the horse.

  1. Clean the wound and the surrounding area. These wounds can be lightly hosed to rid of the contamination of dirt and mud. Take care not to drive dirt deeper into the wound.
  2. Make a decision as to whether further medical treatment is required. This should be based on the depth of the wound and potential involvement of sensitive structures, such as the tendon sheath, coronary band, joints, tendons, ligaments or lateral cartilages.
  3. Bandage the wound, if possible. Apply a sterile dressing, followed by a layer of cotton wool and coplus or elastoplast. Conform the layer snugly and encapsulate the foot to prevent it from slipping up. This will help stem bleeding and also prevent further contamination from the environment.

The hidden dangers

The heel bulb area and pastern are home to some important structures that, if damaged, can be life-threatening to the horse. The synovial structures in this region include the digital flexor tendon sheath, the navicular bursa, coffin joint and pastern joint. Infections in any one of these is problematic.

The coronary band is the structure that produces the hoof wall. If damaged, hoof wall growth can be compromised, often leading to unsatisfactory cosmetic results or functional abnormalities. Other soft tissue structures in this area include the collateral cartilages, collateral ligaments and flexor tendons. These are all susceptible to damage and, in severe traumatic cases, there may also be bone damage. Bony injuries are usually detected with radiographs.

Treatment

A full assessment of the area is vital to assessing the structures involved. Palpation and visualisation may be all that is required and, in more serious cases, radiographs and an ultrasound examination may be utilised. Once evaluated, a decision can be made regarding the treatment options and prognosis for the case.

Suturing of the wound can be performed on the standing horse under local anaesthesia or with the horse under general anaesthesia. The latter is usually reserved for extensive injuries and wounds involving the synovial structures. Most injuries require the horse to be placed on antibiotics and antiinflammatories, and tetanus prophylaxis is essential.

Support of the wound will vary depending on the extent of the injury. Bandaging alone may suffice. However, cast support is usually required, especially for the deeper and more extensive wounds. Casts assist in the healing process by limiting movement in the area and, therefore, protecting the suture line. This results in a faster return to function and a more cosmetically-pleasing result.