The hock is the joint located between the tibia and tarsal bones in a horse’s leg and is the equivalent of the human ankle joint. Hock injections are a veterinary procedure in which a long-acting corticosteroid, or hyaluronic acid, is injected into the joint space of a horse’s hock in order to decrease inflammation within the joint and to increase the viscosity (thickness) of the joint fluid. By reducing inflammation, pain is reduced and it allows the horse to keep moving, and less inflammation means less risk of chipping or damaging the delicate lining of the joint and causing permanent damage. Your horse may need hock injections if you notice changes in the hock, general signs of pain, or signs of localized pain in the hock. The first thing to do is to determine if your horse has a lameness problem and the next is to localize the issue to the hock.
Identifying Lameness Problems
1. Understand that signs of pain can point to a number of injuries. There is considerable overlap between signs of pain in the lower back, hip, or hock, however a horse that shows any of the following symptoms should be investigated to find the cause of the pain. The methods described in the previous step can help to determine if the pain is caused by the hock.
2. Notice behavioral signs of pain. Some horses interpret pain as something that is attacking them and their instinct is to flee away from it. Thus some horses become cranky when ridden and charge at jumps, or refuse fences, or buck when they were previously mild-mannered.
3. Consider whether or not your horse is working as hard as normal. Another common presentation is that the horse does not work to his full potential.
4. Notice if your horse begins riding heavy on the forehand. This phrase means that your horse tries to take weight off his hind quarters and shifts his center of gravity forward.
5. Take note if your horse is not engaging his back end. For fluid movement, the horse uses the power in his back end and bunches his hind legs beneath him to provide forward impulsion.
6. Keep track of your horse’s ability to jump. Jumping requires the horse to shift his weight backwards and place a considerable extra load on his hind legs. If soreness or pain is present, he may try to avoid this discomfort by not fully using his muscles to propel himself upward.
7. Note any challenges your horse has with landing after he jumps. Landing after a jump involves tucking the hind legs beneath the body so as to provide the spring to push the horse forward onto his next stride.
8. Look at the way your horse stands. Hock pain or general hind end discomfort alters the way a horse stands. He tends to shift his weight so as to minimize stress on the sore leg.
9. Assess whether your horse’s gait has changed. Pain alters the way the horse moves, which is referred to as his "gait". Hock and back end pain tends to make the horse "mince" or take shortened strides with his hind legs. He transfers weight onto his forelegs, which gives him a hunched silhouette with his hind quarters tucked under and head carriage low.
10. Watch for symptoms of disuse atrophy.
11. Consider contacting a vet to further the assessment. If you're sure your horse has a mobility issue, it is a good idea to call in the vet to give the horse a thorough check over. If you wish to continue the assessment yourself, localize the problem to the hock.