Horse Hock Injuries

Lameness

A Pain in the Hock
Diagnosis and Treatment of Hock Lameness

Does you horse seem to be under performing? Does he show any of the symptoms listed below? Problems in the hock may be a contributing cause to your horse's behavior. The hock is quite complex. The hock joint is on the lower rear leg just below the stifle. Each hock has ten bones and four joints. However, often these are not the culprits. Instead, inflammation may be the root of the problem. Addressing the reasons for that inflammation may really help with hock lameness problems.

• Reduced stopping ability
• Difficulty in turning
• When jumping knocks down rails
• Refuses jumps
• Problems picking up the correct leads
• Horse appears to have soreness in his back
• Swelling or heat on the inside of the hock joint
• Pain if pressure is applied in above area
• Lame or off on hard ground
• Is your horse sickle hocked?
• Visually from the back does your horse keep his back legs in toward the midline as he travels? Does he put his back legs down in an outward direction (with a pronounced motion) just before they touch the ground? When exercising in a circle, take note. Does one leg have a shorter stride than the other. As the horse moves in a circle the affected leg usually has a shorter stride when on the outside of the ring.
• The hock does not flex freely. Usually a horse will drop on his sound side if he is lame in or below the hock. If a horse is lame above the hock he will drop his lame side.

The hock does not flex freely. Usually a horse will drop on his sound side if he is lame in or below the hock. If a horse is lame above the hock he will drop his lame side. There are a number of causes of hock lameness. Not all are mentioned above and below. However, this is a good start.

• Wounds and injuries
• Capped Hock - when acute-Horses may suffer from "capped hock," which is caused by the creation of a false bursa, a synovial sac beneath the skin. Capped hock is usually caused by trauma such as kicking or slipping when attempting to stand. In the absence of a wound, it does not require immediate veterinary attention and is usually only of cosmetic significance. On the other hand, a wound into the calcanean bursa is a serious problem. A capped hock is extremely unlikely to be a cause of lameness, even if severe. Osteochondrosis dissecans, or OCD is a developmental defect in the cartilage or of cartilage and bone seen in particular locations on the surface of the tarsocrural joint. This condition is typically discovered when the horse is young, and is one cause of bog spavin.

• Sprain - Sprung Hock
• Thoroughpin - (Bursal enlargement) There are two fluctuating swellings above the hock on either side of the Achilles Tendon. There is not always lameness with this.
• Bog Spavin - This is a distension of the true hock joint capsule. There is inflammation. There is swelling in the front of the joint. There may be severe pain, lameness and fever. Distension of the tibiotarsal joint with excessive joint fluid and/or synovium is called bog spavin.
• Bone Spavin - Exostosis on the lower and inner part of the hock. The hock does not flex properly. The toe drags. Most horses will go lame if turned sharply. Lameness often decreases with exercise. Degenerative joint disease of the tarsometatarsal or distal intertarsal joint is referred to as bone spavin. An X-Ray will confirm bone spavin. After surgery to remove bone and cartilage fragments most horses can often return to full work.
• Occult Spavin - Same as bone spavin without exostosis. (A benign bony growth projecting outward from a bone surface)
• Curb - Ligament sprain at the back of the hock. This can usually be found about 5 inches from the point of the hock. There will be a hard swelling, lameness, and difficulty in extending the hock. Curb, or tarsal plantar desmitis, is traditionally considered a sprain of the plantar ligament, which runs down the back of the hock, serving functionally as a tension band connecting the calcaneus, the fourth tarsal bone and the fourth metatatarsal bone. Recent work has shown that curb can be caused by damage to one of many soft tissue structures in this region.
• DOD, OC,OCD, and SBC Medical DOD, etc.

Some of these cases are very subtle and to determine the cause of the pain requires a careful exam by your vet and x-rays. Multiple treatments are available for arthritis of the hocks, including cortisone injections, so if your horse is not performing up to par, contact your local equine vet for an exam.

Hock

The hock of the horse is equivalent to the human ankle. Although the tarsus refers specifically to the bones and joints of the hock, most horsemen refer to the hock in such a way to include the bones, joints, and soft tissue of the area. The hock is especially important in equine anatomy, due to the great strain it receives when the horse is worked. Jumping, and movements that require collection, are some of the more stressful activities.

Hock's Primary Joints and Bones

• Tibiotarsal or Tarsocrural joint
• Proximal Intertarsal joint or Talocalcanealcentroquartal joint
• Distal Intertarsal joint or Centrodistal joint
• Tarsometatarsal joint
• Talocalcaneal joint
• Talus
• Calcaneus
• Central tarsal bone
• 3rd tarsal bone
• 3rd metatarsal bone
• 4th tarsal bone
• Fused 1st and 2nd tarsal bone

Conformational Defects

Because the hock takes a great deal of strain in all performance disciplines, correct conformation is essential if the horse is to have a sound and productive working life. Common conformational defects include sickle hocks, post-legged conformation/straight hocks, cow hocks, and bowed hocks. Depending on the use of the horse, some defects may be more acceptable than others. I would also like to note here, that many "gaited" horses tend to have sickle or cow hocks. The four-beat gaits that they perform are smoother and the horse is able to get "under himself" better with this sort of conformation. They move differently than horses that are not gaited and are used for different purposes. I have never had a gaited horse with hock problems. However, gaited horses may have hock problems just like any other horse.

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