Hind-limb flexion
EAG might be able to help veterinarians make more accurate and specific osteoarthritis diagnoses in horses. | Alexandra Beckstett/The Horse

Healthy cartilage is vital for equine joint health, allowing joints to move freely and painlessly by reducing friction between bones and distributing loads during movement. Untreated damage to horses’ cartilage from injury or wear and tear leads to osteoarthritis.

Electroarthrography in Horses

“Electroarthrography (EAG), a new technology, has the potential to transform the detection of equine joint disease and improve horse welfare,” said Adele Changoor, PhD, staff scientist at the Lunenfeld-Tanenbaum Research Institute and assistant professor at the University of Toronto, in Ontario, Canada.

When horse loads a joint, the cartilage produces electrical signals, called streaming potentials, that provide information about cartilage composition, structure, and load-bearing properties. Veterinarians can use EAG to measure these streaming potentials with electrodes placed on the skin surrounding a joint, Changoor explained. “So, by measuring EAG signals, we can get an idea of how healthy the cartilage is,” she added.

“In our study, which consisted of two separate experiments, we investigated relationships between externally measured electroarthrography in limbs of live and deceased horses and measurements of cartilage streaming potentials made by directly compressing cartilage in weight-bearing areas of the equine fetlock joint,” said Changoor.

In the first experiment, researchers performed EAG on the fetlock joints of three live horses. In a separate experiment they measured streaming potential on horse joint explants (tissue removed from an animal and stored frozen until testing) from cadaver limbs on which they simulated joint loading in the laboratory. The researchers then opened the joints to directly measure cartilage streaming potentials using a handheld probe to compare with the external EAG results.

“EAG is well tolerated in live horses,” said Changoor. “It is more sensitive to early cartilage degeneration than radiography and could enhance a typical lameness examination and the diagnosis of joint disease.” She reports that EAG is not only more affordable than arthroscopy (exploring the joint surgically with a small camera) and MRI but also noninvasive and can be performed by veterinarians on the farm, making it readily available and convenient.

Take-Home Message

“Our study’s findings support further work on electroarthrography to develop it into a tool that could be extremely useful for diagnosing and managing joint disease in equine veterinary medicine,” said Changoor. “In addition, this technology could potentially help monitor cartilage changes resulting from the treatment of osteoarthritis in horses.”