Page 110 - January 2019

Dealing with Ringbone
“Ringbone is an osteoarthritic condition that can be caused by an acute injury to that region, with cartilage damage or instability of supportive ligaments of the joint, or it can be due to chronic repetitive use such as continual concussion and wear.”
Heather Smith Thomas
by Heather Smith Thomas
Ringbone is the common term for osteoar- thritis of the pastern joint or the coffin joint. Todd Allen, a farrier in Vandergrift,
Pennsylvania, has dealt with many cases of ring- bone, and says this problem occurs most often in the front limbs, and can be very painful if it is articular (in the joint). “When I am working with a horse that has ringbone, the first thing to deter- mine is whether it is articular or non-articular. Is it in the joint, or near or next to the joint? Does it affect the joint, or not?” he asks.
“If it does not affect the joint, I don’t worry about it in terms of soundness, and consider it a blemish,” he continues. “The bony growth or calci- fication deposit may grow and expand, but if it isn’t causing pain and lameness, it’s not much concern.”
If it affects the joint, however, the horse needs medical help from a vet and mechanical help from a farrier to alleviate the pain and lameness as much as possible. “The veterinarian will take x-rays, since that’s the only way to know exactly where
it’s located and what’s going on. From a shoeing standpoint, I need to know what I am dealing
with and how bad it is.” The veterinarian can also recommend treatments that might help reduce the pain and lameness.
If ringbone is in the joint, where it is located can make some difference in how the farrier can help the horse move more comfortably by means of special trimming and shoeing.
“Age of the horse can also be a factor, but the bottom line is that ringbone is ringbone,” says Allen. “I do my best to figure out how to deal with it and find comfort for the horse. If the horse is lame, we do what we can to relieve that discom- fort. The best thing we can do as farriers is work with the vet and what he/she finds, whether it’s high ringbone, low ringbone, etc., and the exact location, and then see what we can do to make the horse more comfortable in its movement.”
CAUSES
Dr. Troy Herthel of Alamo Pintado Equine Medical Center in Los Olivos, California, says high ringbone involves the pastern joint, whereas low ringbone involves the coffin joint. “High ring- bone seems to be more common and can develop from a number of different causes. Ringbone is
an osteoarthritic condition—a degenerative joint disease that can be caused by an acute injury to that region, with cartilage damage or instability of supportive ligaments of the joint, or it can be due to chronic repetitive use such as continual concus- sion and wear. Other issues, such as pastern joint subchondral bone cysts or chronic subluxation of the joint, can also lead to ringbone,” he says.
“Chronic repetitive trauma is a common cause, especially in horses that perform in athletic careers,” says Herthel. All breeds are susceptible to pastern injuries that could lead to ringbone. Conformation, such as straight, upright pasterns or toed-in stance, may play a role in whether or not the joint has more stress. Regardless of pastern angle, however, any active athletic horse can suffer injury.
“Any increase in concussion and pressure can lead to joint trauma. Over time this cumula-
tive effect may damage the cartilage and lead to arthritis. Another cause, which is less common,
is anatomical abnormalities which could lead to juvenile arthritis in a young horse,” says Herthel. “The joint may not be developed appropriately, and we may start to see lameness or pastern joint swelling in a weanling or yearling with early-onset ringbone. The young horse may also have devel- opmental abnormalities within the joint cartilage, such as OCD (osteochondrosis dessicans), that may lead to ringbone.”
FUSED PASTERN JOINT
“Whenever the pastern joint is disrupted
and develops severe arthritis, the body tries to immobilize the joint to halt the instability and pain,” Herthel says. “This process produces a significant amount of bony reaction around the joint, which produces the ring-like appearance to the lower limb, hence the name ringbone. Some horses, especially those not being used for athletic purposes, can be allowed to self-heal and fuse that joint themselves. This is called ankyloses and some of them do surprisingly well, but this process can take a long time and most horses would have some degree of observable lameness.” It is amazing what the body can do to heal itself.
Horses in which the joint has fused either surgically or naturally, may travel sound and without pain, but may have an altered gait due to
106 SPEEDHORSE, January 2019
EQUINE HEALTH