The hock is the joint that sits between the tibia and tarsal bones in a horse's leg. Hock injections are a veterinary procedure in which a long-acting corticosteroid or hyaluronic acid (or a combination of the two) is injected into the joint capsule of a horse's hock. The aim of this therapy is to reduce inflammation in the hock and increase the viscosity (density) of the synovial fluid. If you notice changes in the hock, general indications of pain, or signs of localized pain in the hock, your horse may need to have hock injections.
Steps
Method 1 of 2: Recognizing the General Signs of Pain
Step 1. Indications of pain can indicate a number of injuries
There is considerable overlap between signs of pain in the lower back, hip and hock, and a horse exhibiting some of the following symptoms should be examined for the causes of the pain. The methods described in the previous step can help determine if the pain is caused by the hock.
Step 2. Watch for behavioral signs of pain
Some horses interpret pain as something attacking them, and their instinct is to flee. So some horses become irritable when mounted, swerve at jumps, reject obstacles, or buck while before they were tame.
A sign of pain can be a change in temper, such as trying to bite the owner when he is grooming his rear, bucking, or a general bad mood
Step 3. Assess whether the horse is working hard as usual
Another common demonstration is that the horse is not working to its full potential. Try to limit the suffering by not straining, which could mean that:
- It doesn't move as fast or as easily as it used to.
- When he jumps, he does not reach his normal height.
Step 4. Notice if the horse begins to move with the weight on the front
This means your horse tries to take weight off the hindquarters and shift its center of gravity forward. When it behaves like this:
- It puts more weight on its front legs and moves harder because it has to try harder to lift its front legs.
- Pain alters the way the horse moves, ie its "gait". Pain in the hocks or in the rear causes the horse to walk in small steps with the hind legs. It transfers weight to its front legs, which gives it a hunched silhouette, with its hindquarters tucked under and its head down.
- When you mount the horse, ask a friend to stand parallel to you and film your movement. See if the horse lowers its head to counterbalance its hindquarters, and see if all legs are taking equal steps or one is taking shorter steps than the other.
- When you mount the horse, ask a friend to stand at a safe distance behind you and take a video. See if your hips move up and down equally. A horse with a sore hind leg will try to protect that leg with the result that the hip will move less.
Step 5. Notice if your horse is not using the hindquarters
For the movement to be fluid, the horse uses the energy found in the hind leg, under which it groups its hind legs to provide the forward thrust.
If the horse associates pushing on its hind legs with pain, it will be reluctant to use its hind leg, and will likely move slower than normal
Step 6. Take note of the horse's jumping ability
To jump, the horse has to shift its weight backwards and add even more load on its hind legs. If cramps or pain are present, they may try to avoid this by not using their muscles fully to push themselves up.
Your horse may soon lose height, which means it will bump into obstacles it previously jumped easily
Step 7. Notice any difficulty the horse has in landing after the jump
Landing after the jump involves tucking the hind legs under the body to provide the spring that propels the horse forward towards the next stride.
When your horse has a hind leg that hurts it, it may slip and land awkwardly
Step 8. Observe the way the horse stands upright
Hock pain or general pain in the rear end alters the way the horse stands erect. He tends to shift his weight to minimize pressure on the sore paw.
- When standing, he may preferably rest a paw.
- He may also have a tendency to stand erect with the painful leg tucked under his belly so that the hock is straight and the leg does not project any weight on it.
Step 9. See if the horse's gait has changed
Pain alters the way the horse moves, ie its "gait". Pain in the hock and rear extremity tends to cause the horse to shorten the strides with the hind legs. It transfers weight to its front legs, which gives it a hunched profile, with its hindquarters tucked under and its head low.
- Since flexing the joint is painful, the horse may not lift its leg accurately and may have a tendency to stumble.
- A useful tip is to let the horse walk and trot on the sand in order to follow the footprints of its hooves. The painful paw tends to move towards the center line, rather than following that of the corresponding front paw.
- If the hock is injured, the horse may have difficulty walking backwards in a straight line, as the sore leg takes shorter steps, which leads to a sidewardly sloping curve that causes pain.
Step 10. Look for symptoms of amyotrophy
If you notice that there is a loss of muscle mass above the thigh and hip of the sore leg, the horse may have a hock problem. This loss of muscle mass is the result of atrophy, which means that the horse protects the leg by using it less. When not used, muscles can begin to lose mass. However, be aware that amyotrophy can arise from pain in any part of the limb, not necessarily in the hock.
Step 11. Consider contacting a veterinarian for further guidance
If you are certain that the horse has a movement problem, it is a good idea to call your veterinarian and have him check the situation. If you still think you can manage on your own, try to locate the problem in the hock.
Method 2 of 2: Determine if Pain is Caused by the Hock
Step 1. Look for signs of enlargement
An injury to the hock, such as a sprain, causes damaged tissue to release hormones, such as histamine, prostaglandins, and bradykinin. These chemicals act on blood vessels and make them permeable, so that fluid builds up in the area of the injury, causing it to swell. This has a double effect: the liquid helps to isolate any harmful substance from the general circulation, and it is also rich in white cells that protect against infection.
If you are unsure whether one hock is enlarged, compare it to the other. Check to see if areas that are normally concave are swollen and full. Sometimes running a hand over the normal hock and then the injured hock can help you feel the difference immediately
Step 2. Look out for symptoms of disuse atrophy
If you notice a loss of muscle mass in the thigh and hip of the affected leg, your horse may have a hock problem. This loss of muscle mass could be the result of "disuse atrophy," which means that the horse has protected that leg and underused it. When muscles are not used, they begin to waste away.
Step 3. Check if the hock is warm
Inflammation of the hock generates heat. For this reason, you should touch it on the hock: if the area is warmer than the surrounding parts, your horse may have suffered a hock injury.
Compare the temperature of the injured hock with that of the other leg
Step 4. Perform the bending test
The basis of this test is to flex (bend) the hock to an extreme position and hold it there for a period ranging from 30 seconds to 3 minutes. The idea is that if the hock is already sore, your horse will experience an increase in lameness when you release the leg. Here's what to do to perform this test:
- Before the flex test: Stand behind the horse and let him trot out in a straight line. Try to see which of the two hips moves up and down the most.
- During the flex test: flex the hock and have the horse repeat the trot. The idea is that if the hock is sore, the lameness will be worse than before the flexion.
- The reasoning behind this flexion test is slightly flawed, as it is impossible to flex the hock joint in isolation. The action of lifting the leg and keeping it flexed also changes the position of the fetlock and hip joints. So, although most of the pressure is exerted on the hock joint, it is possible for the pain to increase in another joint, confusing the results of the flexion test.
Step 5. Have a vet do a regional nerve block test
The idea behind this test is that if the hock pain is temporarily removed, a horse that was previously lame should be fine after the block. You should wait for the vet to perform this test. Here's what to do during the test.
- First, the vet sterilizes the skin, where the needle will be inserted, with a surgical disinfectant. A 38 mm 20 or 22 gauge needle is used to inject approximately 1 ml of local anesthetic just under the skin, at the passage of the skin branch of the superficial and deep fibular nerve.
- After injecting the local anesthetic, the flexion test should be done within 15 minutes, because the anesthetic can spread to the lower extremity of the limb and numb the paw, which can also alter the gait.
- If the extremity of the limb becomes excessively numb, the horse may drag the leg and rub the back of the hoof. If this happens, it is advisable to bandage the end of the paw to reduce the risk of abrasion.
Step 6. Consider having him undergo an x-ray examination
If a flexion test and regional nerve block indicate hock pain, an x-ray is sometimes done. Radiography is useful in locating fractures, bone changes (which occur with arthritis), bone infections and cancer, joint capsule enlargement.
- To perform the x-ray, the vet will work with the horse in an upright position and use portable x-ray equipment. Two images are generally taken: a side view exposure, taken from the side (looking towards the horse), and an anteroposterior view taken in front of the hock joint, looking towards the horse's tail.
- It is possible that the X-rays do not detect anything but the horse continues to feel pain. This is because X-rays show us bone damage rather than inflammation of the joint lining. Many vets prefer to rule out any fractures before giving hock injections, because the steroid may delay bone healing if that is the underlying reason for the lameness. If the x-rays are okay but the hock is still painful, this is a strong indication for giving a hock injection.
Step 7. Seek help from a veterinarian
The vet will look for other telltale signs of discomfort, such as head swing, unusual hoof positioning, shortened steps, and weight shift. It will also try to see if the horse's weight is evenly distributed between the opposite diagonal pairs of legs. Lameness tends to be more noticeable at slower rates, such as during a simple walk or trot.
Advice
- If your horse has an injured hock, he may have difficulty walking backwards in a straight line, because the sore leg takes shorter strides and then the horse naturally moves in a curve along the affected side.
- Seek help from a veterinarian. The vet will look for other telltale signs of distress, such as head sway, unusual hoof placement, shortened strides, and weight shifts. He will also try to see that the horse's weight is evenly distributed between the diagonally opposite pairs of legs. Lameness tends to be more noticeable at slower gaits, such as walking or trotting.
