Hock problems are an extremely common lameness in any active horse, regardless of discipline, because of their complexity. Afflictions range from mild “strain” to bursitis to degenerative arthritic conditions. It’s also a relatively common site to find OCD.
The hock is a complicated joint, involving five levels of bone — tibia, three rows of tarsal bones, metatarsus/cannon — and the four joint spaces between them. The joint between the tibia and the upper tarsal bone travels through a wide range of motion, allowing the hock to flex, and resembles the elbow in many ways. The lower joints have much less movement and look more like the knee, but they don’t open and close to the extent the knee joint does.
The bones are connected by an intricate system of tiny ligaments inside the hock joint, which is then encased in the joint capsule. The tendons of various muscles run beside or attach to the hock from the outside and one, the cunean, crosses the front of the hock, with a large bursa located underneath this tendon.
Causes Of Pain
Hock pain can originate from a problem in any of the structures we just described. Basically anything that requires exaggerated flexion and/or weight bearing on the hindquarters stresses the hocks. However, certain activities are particularly stressful on the hock joint, including:
• Turns on the haunches, especially at speed
• True collected gaits
• Breeding (stallions)
In addition, some common conformation faults result in the hocks being loaded unevenly, predisposing to them to injury.
• Sickle-hocks: The hind cannon bones run forward at an angle rather than being directly perpendicular with the ground. This forces the front edges of the bones closer together.
• Cow-hocks: A horse that is unusually wide behind tends to overload the inside of the hock joint, a common place for arthritis (bone spavin) to develop.
• Overly straight hind leg: This usually causes more problems with the stifle than the hock, but a horse with a straight hind leg has higher concussive forces on all the leg joints. Horses with this conformation may be more prone to cunean bursitis.
Hock Pain Symptoms
Differentiating hind-limb lameness sources takes some skill and experience. Some symptoms are fairly general and only indicate that there’s pain somewhere in the horse’s hind end. These include:
• Uncharacteristic aversion to work
• Heavy on the forehand
• Reluctance to engage behind
• Jumping in a flat frame
• Refusing jumps
• Collapsing or slipping behind on turns and when landing after jumps• Less muscular definition behind or on one side
• Stabbing toes when he moves
• An exaggerated twisting motion to the hocks, especially when first moving off
• The foot placed downward toward the center of the body rather than in the line of the front print
• Reluctance to negotiate inclines
• Preferentially unloading one hind leg when at rest, or frequently shifting weight between hind legs at rest
• Hip pain, which may be a primary problem but often is a complication of hock pain
• Lumbosacral-area back pain.
There are no therapeutic trimming or shoeing techniques for hocks, beyond restoring the foot to a good functional shape and configuration. However, shoes with excessive holding action, including grabs and caulks, should be avoided. If possible, allow the horse to go barefoot during the treatment. This allows the horse to choose for himself the most comfortable way to move, land and break over.
• Strain/Sprain: Soft-tissue sprain/strain in the hocks is common but difficult to diagnose. Lameness will be relatively mild, more a “stiffness” than an actual “limp.” An X-ray won’t show the problem, but the hocks may feel warmer than normal — or one warmer than the other, if one hock is affected. Increased fluid in the joint is possible but may be difficult to detect with certainty.
Treatment: With a strain, avoid formal exercise for a few days but allow the horse to move around on turnout to keep stiffness to a minimum. If hocks are obviously hot, cooling boots or cold-water hosing should be used until the temperature returns to normal. Mild liniments at night and before work will help alleviate any stiffness/soreness when the horse is being returned to work, but while the area is still actively inflamed we would recommend using Sore No-More liniment (www.equilite.com 800-942-5483) or DMSO.
• Cunean Bursitis: This is inflammation of the bursa that sits between the cunean tendon and the hock, located along the lower and inside aspect of the joint. If the foot is held just slightly off the floor, weight shifted to the opposite leg so that the side being examined is unloaded with the hoof only in toe-touch position, you will be able to identify the crossing tendon easier and can check for a feeling of fullness under the skin above and below the course of the tendon. Inflammation may be a primary problem or in association with strain or bone spavin/arthritis.
Treatment: Rest, cooling and a short course of anti-inflammatories is indicated until the heat, pain and swelling resolves. If your veterinarian confirms bursitis in this location, a local injection of a low-dose corticosteroid may be recommended. If the horse has recurrent problems, definitive treatments include:
Cunean tenectomy, which is the surgical removal of a portion of the cunean tendon where it crosses the hock. It’s also called “cutting the jacks.” This relieves pressure on the bursa underneath without causing any gait disturbances. Lay up is minimal and light exercise often recommended soon after the procedure to avoid any problems with restrictive scar tissue developing.
Cryotherapy (“freeze firing”), which involves freezing several points in the area deeply to reduce pain. It may also obliterate the bursa. Freeze firing is effective when done properly, but the frozen spots will have permanently white hairs. Lay-up time is minimal.
• Bog Spavin And OCD: Bog spavin is an old term that refers to horses that have an accumulation of excessive joint fluid, leading to an obviously swollen hock. It might occur with fracture or a severe strain, but most cases have an underlying OCD (osteochondritis dessicans ) problem. Basically, OCD occurs as a defect in the connection between bone and cartilage, forming cysts, cracks or a cartilage flap.”
The increased joint fluid is a physiological response to irritation, usually from an OCD fragment. While it looks terrible, many horses with bog spavin are actually sound because of the increased lubricating effect of the fluid.
Treatment: Large, free fragments may need to be removed surgically. Injections of the joint with corticosteroids or hyaluronic acid (HA) usually don’t help much and, when they do, indicate ongoing active irritation that requires surgery. Lay-up time averages one to two weeks in the stall, followed by gradual resumption of activity for four to six weeks.
• Bone Spavi n And Arthritis: Arthritis of the hocks is common and may involve either the lower joint or the joint between the rows of tarsal bones.
The area of the joint underlying the cunean bursa and tendon is a common spot for arthritis to develop. Advanced cases may develop fusion, a bridge of bone that connects adjacent rows of tarsal bones and prevents movement.
Treatment: Early cases of arthritis are treated like arthritis anywhere, with a combination of joint nutraceuticals, local injection and sane exercise. In advanced cases, it often becomes a balancing act between keeping the horse comfortable enough to perform and encouraging enough inflammation to result in fusion/bridging.
Odd as it may sound, hock fusion is desirable in these cases, since the involved joints normally have limited movement anyway and fusion keeps movement, therefore further irritation, to a minimum. Although you’ll often hear that once it fuses the joint will be sound, in reality this rarely happens, and a variety of chemical and surgical techniques have failed to produce complete fusion.
Frankly, once your horse has symptoms of hock arthritis, you’re going to have to deal with it for the rest of the horse’s life. That sounds discouraging, but with proper management many horses continue to work and compete successfully with hock problems.
Your veterinarian may suggest that an intra-articular injection will benefit the horse. Joint injections performed under appropriate sterile conditions have a low risk of adverse reactions and effectively control inflammation and pain.
Some veterinarians prefer corticosteroids, others hyaluronic acid, and others use a combination of both. When combined, usually it’s corticosteroids in the lower joint and HA in the upper joint, where there is more movement. Not all horses require intra-articular therapy, though, and we believe you can get better results if you stretch out the intervals between needed injections with proper management.
You’ll need to work closely with your veterinarian to both diagnose and then treat your horse’s hock problem. Our information should help you communicate at a productive level in determining the course of action.
Control of a hock problem requires proper management and constant surveillance of the changes. Your farrier is important in keeping the trims balanced and the hoof properly positioned under the leg.
Most hock problems will benefit from some TLC in the form of a cooling/warming boot. Our dream hock-cooling boot would be lightweight and secure enough to stay in place without support from below, and have extended cooling time.
The Cold One Universal Hock/Knee Wrap fits the bill closely and at a good price. It can also double as a neoprene/warming wrap for horses with hock stiffness, which impresses us. However, it’s only available in one size, which we found too small for a large-boned horse.
For those with larger horses, we suggest the comparably priced Professional’s Choice Hock Boot. Although it wasn’t as lightweight or form-fitting as other boots, it does stay in place better than most. It, too, can double as a neoprene warming boot and is durable enough to serve as a hock protector during shipping.
For Best Buy, it’s Reitsport, from Horse Tech. This boot is of a moderate weight and achieves good levels of cooling.