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Protect Horses from Temporohyoid Joint DiseaseBy Kentucky Equine Research Staff · June 12, 2017

When horse owners purchase joint supplements, we frequently think of supporting high-motion joints: knees, ankles, stifles, and hocks. But even small joints, like the temporohyoid joint in the skull, can have a huge impact on a horse’s overall health.

The temporohyoid joint is the junction between the skull and the hyoid apparatus—a series of small bones that supports the horse’s throat. Like any joint, which is simply a connection between two bones, inflammation can incite a cascade of events that ultimately leads to osteoarthritis (OA). Instead of lameness, OA of the temporohyoid joint can result in even more serious clinical signs, such as dysfunction of the facial or vestibulocochlear nerves (resulting in facial paralysis or head tilt), head tossing, difficulty swallowing, bit avoidance, ear rubbing, and seizure-like activity.

Diagnosing OA of the temporohyoid joint can be achieved via standard radiography (X-rays), computed tomography, or standard endoscopy with the endoscope inserted into the guttural pouch to directly visualize the joint. Once diagnosed, two treatment options exist: surgical or medical.

Two surgical procedures are possible, both with pros and cons. Both procedures, one called a partial stylohyoid ostectomy (PSHO) and the other called a ceratohyoid ostectomy (CHO), aim to reduce stress on the temporohyoid joint in order to avoid severe neurological issues. To determine if one of the surgical procedures was more effective than the other and how medical management weighed in, one research team* reviewed medical records of 53 horses diagnosed with temporohyoid joint OA treated either surgically or medically. The researchers found the following:

  • Medical therapy, consisting of antioxidants, anti-inflammatories, and/or antibiotics, was significantly associated with a negative outcome;
  • Survival time was significantly shorter for the medical group compared to the two surgical groups;
  • No significant difference in survival occurred between the two surgical groups; and
  • The older the horse at time of diagnosis, the less likely for survival.

“Based on these results, the study authors suggested that surgery results in longer survival times, a better outcome, and a higher rate of return to previous use. The study did not include horses administered a joint supplement, though an ounce of prevention is worth a pound of cure, as the saying goes,” noted Kathleen Crandell, Ph.D., a nutritionist for Kentucky Equine Research (KER).

Crandell added, “KER offers several quality joint supplements, including KER•Flex that contains both glucosamine and chondroitin sulfate; Synovate HA, a high molecular weight hyaluronic acid; and EO•3, a marine-derived fish oil supplement with both DHA and EPA.”

Australian horse owners should also look for Glucos-A-Flex.

*Espinosa, P.M., J.E. Nieto, K.E. Estell, et al. Outcome after medical and surgical intervention in horses with temporohyoid osteoarthropathy. Equine Veterinary Journal. In press.