Last summer, researchers at the Western College of Veterinary Medicine (WCVM) experimented with a way to stop laminitis in its tracks, using a single screw to prevent coffin bone rotation.
The term laminitis refers to the inflammation of sensitive structures within the hoof called lamellae. There are numerous causes, and depending on the trigger, a horse may recover fully or the condition may become chronic, leading to founder.
When a horse founders, the lamellae that bind the hoof wall to the underlying coffin bone become inflamed. During this very painful process, the coffin bone loses support at the front of the hoof, begins to separate from the hoof wall and rotates, or sinks, within the hoof.
During the initial, or acute, inflammation stage, the goal of care providers is to reduce the inflammation with medication or ice in order to prevent the coffin bone from rotating.
Last summer, fourth-year veterinary student Kathryn Carmalt, worked with equine surgeons Dr. David Wilson and Dr. James Carmalt, along with other veterinarians at WCVM, to develop a new way to halt coffin bone rotation.
“All of the current treatments for laminitis are medical in nature, but the problem is quite physical,” said Kathryn Carmalt. “The bone is rotating within the hoof, so why not stop it mechanically? Why not physically prevent it from rotating, similar to what’s done when stabilizing a fracture?”
The team investigated the possibility of preventing coffin bone rotation in cases of acute laminitis by placing a single screw through the hoof wall and into the bone. After 48 to 72 hours – once the initial inflammation has subsided – the screw can be removed.
Carmalt said so far the outlook for this new treatment is promising. “We have performed biomechanical testing at the University of Saskatchewan’s College of Engineering and proven that a single screw in the coffin bone is strong enough to withstand the forces likely to be placed upon it by the deep digital flexor tendon [during a bout of laminitis].
“Additionally, we’ve developed and tested a technique in normal, live horses. The animals tolerated the screw placement procedure without showing undue discomfort post-operatively. These horses could be managed without the levels of painkillers that are usually necessary in clinical laminitis cases.
“The screws could also be removed, while the horses were standing, without desensitizing their feet – a further indication that the presence of the implant was well tolerated.
“We need to do more development and testing, but this new technique could be a significant advance in treating the disease.”