Arthritis in the small joints of the horse hock is a very common condition affecting all types of horses.  It is not just a disease of old horses; in fact, we regularly see this in horses around seven or eight years old, and it is often picked up in the autumn as the weather gets cold and miserable, and when horses are not worked as frequently.

The hock joint, or tarsus, is equivalent to the human heel, and has an important role in hind-limb movement.

The horse hock is made up of four joints. The upper joint is responsible for extensions and the majority of the hock mobility. The small joints below this are low motion joints that barely flex during movement.

During collected movement, when a horse’s centre of gravity is shifted backwards, the hind limb is placed further forward and under the horse, which increases hock loading and joint compression. All the hock joints can be affected by this.

Here’s an interesting fact:  Did you know that arthritis in horse hocks cannot be linked to a specific breed?  Instead, breeds that are taken out of their historical use are more susceptible to hock injuries and problems.

Signs of Arthritis in Horse Hocks

With hock problems ailing all breeds, it’s important to keep an eye out for signs. What is lameness shouldn’t be mistaken for laziness. While not preventable, when noticed and treated early enough, hock problems can be addressed, and your horse can be made more comfortable by relieving the pain associated with arthritis in horses.

Here are a few common signs of hock problems in horses¹.

Stiffness

More specifically, this refers to stiffness at the start of a ride that eventually goes away. When a horse is suffering from a hock problem, all of the ligaments in the joint tense up and become tighter, trying to protect the joints and bones.

This tightness will eventually be worked out as your horse stretches and moves.

Shifting Their Weight

With arthritis present in your horse’s hocks, your horse would want the weight off of their bad hock even when standing.

It’s natural to change weight on and off a leg while standing and shifting weight while standing isn’t always a sign of hock problems. However, if you notice your horse always takes the pressure off a particular leg, it’s worth checking out.

Changes in Gait

Pain alters the movement of any animal. With pain in the back legs, horses will shorten their gait to take weight off their back. If the pain is severe, they may even shift more weight onto their forelegs, ending up in a hunched position.

Less Spring in Their Jump

When approaching a fence, horses shift their weight into their hind end, allowing them to spring off of the ground and clear the fence.

Horses with hock problems are reluctant to do that. In developing injuries, they may still jump, but with less spring. Keep an eye out if your horse gradually begins hanging their back legs and catching rails.

With horses in severe pain from arthritis in their hocks or a hock injury, they may start refusing. If your horse wasn’t in the habit of stopping before fences and you cannot figure out why they are starting to, take a look at their hocks.

Changes in the Appearance of Their Hock Joint

The hock joint has a particular, recognizable anatomy, and one of the most apparent signs of hock problems is a change in the hock’s appearance. If you notice any deviations from this or notice swelling, tenderness or heat at the hock, it’s time to call your vet.

Your farrier’s feedback

Your farrier may comment on the fact your horse is wearing down the outside of his hind feet and/or spreading the shoe which, again, is the horse using his hindlimbs differently to avoid pain. Your farrier may also notice the horse becoming more difficult to shoe the hind feet as flexing the hock will be painful.

Diagnosing arthritis in horse hocks

What to expect from a clinical examination:

• a flexion test whereby stress will be put on the joint. This should intensify the lameness.
• injecting local anaesthetic into the joints. If this makes the horse sound it will indicate that the source of the lameness has been found.
• x-rays.

X-rays often only reveal very mild changes as the result of bones adapting to on-going inflammation and damage in an attempt to stabilise the joints and stop the pain.  The inflammation generally reduces as the joints adapt more. This process is called fusion.

Fusing hocks are not necessarily a bad thing and can almost be looked at as a cure. Once the hocks are completely fused the joint is no longer painful and will no longer require joint injections to manage the pain.

In most instances, a fused lower hock does not affect the movement or gait of the horse.

Treating arthritis in horse hocks

Specialised shoeing

Remedial shoeing to support the joint and encourage correct foot fall comes recommended.

Steroid injections

The most common form of treatment is the injection of steroids into the joints.  This will significantly reduce the inflammation in the joint and slow the progression of the arthritis, hopefully reducing the chance of extreme changes.

After a few days of rest the horse starts a work regime, gradually increasing the amount of work over two weeks. Exercise is critically important during this time. It depends on the individual horse as to how many times the hocks need injecting, many horses are treated only once, others need injecting every six months.

NSAIDs

Sometimes using anti-inflammatories alone (such as bute), combined with exercise for a period of time, will help to get the horse through the inflammatory stages of the disease and many older horses stay on a low dose of bute for life.

However, the chronic use of anti-inflammatories carries its own risks:

“Side-effects that we see include gastric ulceration, kidney and liver damage…”

Sussex Equine Hospital

Additional pain treatment

• Rely on aggressive cooling as the primary method of inflammation and pain control during acute flare-ups.
• Avoid activities that overstress the hock during periods of acute flare-ups.
• Maximize turn out and minimize stall confinement.
• Use neoprene or magnetic hock wraps overnight for horses that obviously have early morning stiffness.
• Apply brisk massage with an ointment, a thorough warm-up on the flat when beginning exercise, and the regular use of cooling wraps post-exercise.
• Use a joint supplement

The information provided on this site is for information purposes only and is not intended as a substitute for advice from your physician, veterinarian, or other healthcare provider.

Diagram credit: http://racingfactions.com/equine-anatomy-part-110-horses-vs-humans/
¹ https://www.phdveterinaryservices.com/post/signs-hock-problems-horse
² https://pubmed.ncbi.nlm.nih.gov/25371599/