Alan J. Ruggles
First Aid Care of Limb Injuries
Orthopedic injuries in the horse are potentially life threatening, and proper understanding and application of first aid techniques to protect the limb from further injury can be life-saving. The veterinarian’s understanding of proper immobilization and transport techniques will give the horse the best chance for a good outcome. In addition, orthopedic injuries in the horse are severely distressing to both the horse and its human companions. The veterinarian’s ability to control the situation and provide relief to the horse and clear advice to the client will improve patient outcomes and can make a difficult situation much easier for the patient and owner.
Preparation
A proper first aid program begins with preparation. Experienced practitioners either carry versatile bandage or splint material in their vehicle or have quick access to these materials when an orthopedic injury is encountered. Splints made of wide, thick polyvinyl chloride (PVC) pipe (cut from at least 4-inch diameter pipe) are useful to have on a practice vehicle or at the practice office. Commercial splints, such as the Kimzey Leg Saver Splint or Trauma Boot,1 are versatile first aid devices for injuries up to the level of and including the metacarpophalangeal or metatarsophalangeal joint. Splints can be either premade or custom made with a standard hardware-grade saber saw and PVC pipe. Broom handles, fencing planks, or twitch handles also make adequate splinting material when needed. Sterile and nonsterile bandage material and adhesive bandage tape and duct tape are useful to have quickly available. Casting material is also occasionally used to cast limb injuries or to augment splint application. Lightweight and strong materials that are readily available make appropriate materials for splints (Box 5-1).
Assessment
When confronted with an equine orthopedic emergency, it is important to recognize the complete or potential extent of the injury so that clients can be properly informed of the horse’s status and of their treatment options. Although it is natural to focus on the most obvious or serious injury at some point before transport and referral, a complete physical examination should be conducted to ensure that important additional injuries do not go unrecognized. Assessment should include the overall cardiovascular status of the horse, including blood loss, dehydration, or shock. A high heart rate is typical in orthopedic injury because of pain, but loss in intravascular blood volume as a result of blood loss, sweating, or inadequate drinking can also cause an increase in heart rate and should be assessed and corrected if needed. A horse with an unstable limb will often be in a state of distress. The distress can generally be alleviated by splinting of the limb and providing a means for partial weightbearing. Palpation of the unstable limb may give some indication of the location and extent of the injury, but complete assessment of the injury is best achieved by radiography. If a horse is under great distress from an unstable limb, it may be best to provide support first and then assess radiographically after splint application. Soft tissue injuries of the most seriously affected limb and the other limbs should be assessed. It is important to determine whether soft tissue injuries associated with fractures constitute minor or major complications to fracture repair. Abrasion and puncture wounds from the bone ends of type I open fractures may have a negative effect on fracture repair outcome. However, this risk is relatively low if definitive therapy is to be performed relatively soon. Severe soft tissue injuries in type II or type III open fractures or injuries that cause loss of vasculature often significantly affect decision making and outcomes in fracture repair, and should be recognized and discussed with the owner at the time of examination. Classification of open fractures is summarized as follows:
Control
The equine health care professional should gain control of the emergency situation as it pertains to both the injury the horse has sustained and the emotional distress the owner and associated persons are under. Sedation of the injured horse is necessary in most circumstances to enable evaluation of the injury, perform diagnostic tests, and apply first aid. Sedation should be used judiciously and with an understanding of any associated abnormalities, such as blood loss or shock, that may affect the amount of drug needed. Because of their excited state and associated pain, injured horses respond less predictably to sedation than do noninjured horses. Sedation with an α2-receptor agonist such as xylazine is usually sufficient to allow assessment and first aid. Care must be taken to avoid oversedation, which could make it difficult for the horse to remain standing or complicate transport. A xylazine dose of 0.4 to 0.5 mg/kg is usually appropriate for initial examination. If the horse is trapped or has a limb trapped and is recumbent, heavier sedation or sometimes short-term anesthesia may be necessary to free the horse with a reduced level of risk for the horse and for persons attending the horse. Opioid agonist-antagonists such as butorphanol enhance pain relief and can be given in combination with xylazine. Repeat sedation may be given as needed.
Diagnostic Tests
The attending veterinarian must evaluate the situation to determine what first aid is required. Careful visual and physical inspection of any injured area is essential. A wound that enters a synovial structure may be obvious by visual inspection or may be detected by observing synovial fluid in the wound. Puncture wounds into synovial structures may not be obvious, and detection may necessitate joint aspirates of the affected wound (see Chapter 186). These are not usually performed as first aid procedures but rather are done at a referral center or when clinical signs consistent with synovial inflammation become obvious. Ultrasound is not typically performed on the limbs, but assessment of the thoracic or abdominal cavities to identify any comorbidities involving these areas can be performed if indicated. Radiographic assessment generally gives definitive information about the degree of injury and helps determine possible therapies. The ready availability of direct radiography, instant stall-side evaluation, and ease of electronic transfer of images to referral centers make both assessment and treatment plans more accurate.
