Equine Suspensory Ligament Injury

A horse's suspensory ligament consists of a band of connective tissue that lies along the back of the lower leg and connects the horse's knee to the ankle (fetlock joint). "The primary function of the suspensory ligament is to prevent excessive extension of the fetlock joint during the weight-bearing, or stance, phase of the stride," say equine vets at the Veterinary Medical School of the University of California-Davis. Because this injury can potentially end the career of many sport horses, including racing Thoroughbreds and those animals involved in the jumping, eventing, cutting and reining disciplines, knowing what to look for and how to treat this particular disorder concerns most horse owners.

  1. Causes

    • "One thing that predisposes a horse toward this type of injury is poor hoof balance, with more stress and strain on certain parts of the leg," says Dr. Van Snow of Santa Lucia Farm in Santa Ynez, California in a 2002 article in the "Thoroughbred Times." He states that hoof balance is important as well as making sure the horse is well-conditioned and worked on firm footing. Horses need long-term, physical preparation and stretching of their tendons and ligaments prior to work that requires speed and endurance in order stay healthy and injury free. They also work better in footing that allows for hoof-to-base contact, rather than soft footing where the chances of twisting a hoof or leg are better.

    Types &Symptoms

    • Symptoms of suspensory injury vary depending on the seriousness of the condition. A horse with a pull, bruise or strain may present with mild to severe lameness on the affected leg that comes and goes over a period of days or weeks. Acute (recent) injuries often present with inflammation, heat and pain around the injured area. Chronic (long term) cases result in persistene lameness and thickening of the ligament that can be seen with the naked eye. A horse that has a ligament rupture, or tear, will immediately drop the affected fetlock to the ground when required to bear weight on that leg, says Dr. Ronald Riegel in his book "The Illustrated Atlas of Clinical Equine Anatomy and Common Disorders of the Horse." These animals suffer acute pain and inflammation.

    Diagnosis

    • Equine veterinarians typically use several diagnostic tools to confirm suspensory injuries in their patients. Palpation (deep feeling) of the affected area typically causes a pain response in the horse with the vet able to feel a thickening of the ligament. Many vets require ultrasound imaging and radiographs to confirm the diagnosis because they are able to see enlargement of the ligament branches and any degeneration of the surrounding joint and bone tissue. In her practice, Dr. Janice Young, who is also a certified farrier at Northern Virginia Equine in Marshall, Virginia, also uses thermography, which shows heat in affected tendons, and nuclear scintigraphy, also known as nuclear bone scanning, in making her diagnoses.

    Treatment

    • Treatment of a pulled or strained ligament begins with controlling the inflammatory reaction within the horse's tissues by using cold therapy, usually an immediate application of ice. The ice constricts the blood vessels, slows hemorrhaging and reduces pain. Most veterinarians administer NSAIDs (non-steroidal anti-inflammatory medications) at this point and remove the horse's shoes to lower the heel and straighten the fetlock joint. This relieves pressure on the suspensory ligament.

      Horses with a tear or rupture require surgical repair of the ligament.

    Rehabilitation

    • Dr. Riegel states that stall rest after injury is essential for several weeks to several months with cold therapy alternating with massaging and stretching the injured area. Owners will be able to hand-walk their horse after several weeks of rest while continuing therapy; recheck ultrasound exams will be needed to assess recovery every 60 days. Once the horse is relatively sound, warm, moist heat therapy will increase blood flow to the ligament, speed healing and increase its flexibility. Many horses recuperate when owners comply with veterinary recommendations, but may not be able to return to full, performance levels after this type of injury. Those with a ruptured tendon cannot return to full working potential even after surgery.