Last Updated on February 19, 2022 by Allison Price
These critical joints can be damaged by wear and tear. These are the most recent targeted treatments to prevent hock problems in horses.
Your horse is leaning against the bit, refusing to let his hind end up under him or use his hindquarters while he moves. He doesn’t push through a fence with the force you know he has. Are his skills slipping? Is he regressing in his training Oder is it hock issues?
Your horse’s hind-end driving mechanism relies on the hocks. Jumping and performing collected gaits are particularly hard on the hocks. Tight turns and small circles are also problematic as they load the hocks unevenly, and use twisting force. Horses can develop hock problems when their joints become worn out over time.
This is the bad news. But there’s also good news. Even if your horse has hock problems, you can still take steps to help him work comfortably and prolong his career. We’ll show you what to do and how to fix it.
Hocks, Health and Not
The hock connects the bones of the lower leg (the two splint bone bones along with the cannon bone) to the tibia in the upper leg. But it’s more complicated than that. It is a complex assembly of about half a dozen bones that are designed to absorb shock and flex when the horse puts his hind legs underneath his body. This allows him to propel himself forward.
The tibiotarsal joint is where most of the extension and flexion takes place. The ridge at the end of the tibia runs from front to back and fits into the groove of the squat bone below (the Talus). The working surfaces are covered with slick cartilage. They slide along the groove while your horse extends and flexes the joint. The largest hock bone, which is approximately equivalent to your heel, rises behind the talus. It serves as a brace and prevents the joint’s overextension.
Two small, flat bones (the central and third tarsals) are located below the talus. They are placed on top of each other like pancakes. A few other small bones are located behind the calcaneus, the cannon, and splint bone. This lower (distal), part of the hock has a limited range of motion. They’re designed to absorb shock with thick cartilage pads. The strong ligaments at the sides keep everything in line, so that the hock doesn’t move to one side.
Problems with the hock joints can develop gradually and early signs may not be obvious.
- Horses may experience a fluctuating degree of lameness with or without visible heat or swelling.
- He might seem stiff at first but he will “work it out” as he warms.
- He might resist backing away from the trailer or going downhill.
- His hocks may be in pain from the overtime he does.
The problem often improves when the person is resting but then returns to work. The soreness gets worse over time. He walks slowly behind him, taking short strides or dragging his hind toes.
Mild hock lameness can be detected with a flexion test. You can ask a friend to help you ride your horse or guide it. Standing at your hindquarters facing forward, lift the lower leg just above the fetlock. You should raise it as close to your upper leg as possible, flexing your hock and holding it there for 60 seconds. Next, place the foot on the ground and ask your assistant to immediately start trotting the horse. Your horse may be more lame if it has a problem with its hocks.
These symptoms can indicate trouble but they do not tell you the exact cause. To find out what’s happening, your veterinarian may perform a complete lameness exam and take X-rays.
The Prime Suspect: DJD
Although there are many conditions that can affect the hock joints, it is more common in adult horses (especially those who are performance horses) to have degenerative joint disease (DJD) or arthritis. DJD usually develops in the lower joints and hocks, which are often subject to a lot of stress while your horse is working. Congeniton can play a role. Flaws like cow hocks or sickle hocks (see further) can put uneven pressure on the joints. Post-legged postures cause the joints to flex less to absorb shock. This increases the chance of injury and makes it more difficult for the joint to absorb impact.
Injuries or wear and tear to joints can lead to a series of destructive events. Inflammation of the inner membrane of the joint that produces the viscous liquid that fills it occurs. The fluid that lubricates cartilage surfaces becomes thinner and more watery. The cartilage becomes squeezable and begins to wear away. New bone growth appears where bones have been irritated. This happens most often at the lower hock’s inner side, where small tarsal bone fragments are compressed. This condition, bone spavin, affects both the hocks but is usually more severe on one side.
It won’t stop once bone spavin is present. You can manage the condition and slow down its progression if you catch it early. It is important to reduce joint inflammation, which can reduce pain and joint degeneration. The severity of the condition, the level of pain and the demands placed on your horse’s work will determine what you do.
Management and training program changes can make a difference. To make him more mobile, increase his turnout. Reduce the amount of work that you do, especially if it stresses the hocks. Give him longer warm-ups. Light activity improves circulation and keeps the joint fluid moving. This helps to nourish cartilage. Rocked toes (where the front of the shoe is rolled up at an angle) can help reduce breakover. It is possible to raise the heel or reduce the toe to improve hoof angle. Avoid heel extensions. These are where the heels of the shoes extend beyond the trailers. Extensions can affect the landing and path of the foot and put uneven pressure on your hocks.
Rest and cold hosing (or any other cold therapy) may be helpful if symptoms become severe. Nonsteroidal anti-inflammatory drug (NSAIDs), such as phenylbutazone, can also be helpful. However, soreness can return when horses go back to work. Long-term treatment with NSAIDs could have dangerous side effects. There are many better options available, some both new and old.
The most common and effective treatment for horses with problems in their lower hock joints is joint injection. This injection injects anti-inflammatory substances directly into the joint space.
Corticosteroids or HA: Joint-injection agents are typically corticosteroids. They have powerful anti-inflammatory properties. They can be used in combination with hyaluronic (HA), which is a natural component of cartilage, and joint fluid. It’s the substance that makes fluid viscous. Here are some things to look out for:
- Your horse will usually rest for a few days after the procedure, then resume work. The full effect may not be apparent for two weeks.
- Dependent on the severity of the problem and how hard your horse works, benefits can last from weeks to one year. The effects may be extended by combining injections with other methods. Some people report longer-lasting effects from Surpass?, a topical anti-inflammatory Surpass?. However, there is no data.
- Side effects are very rare. Although rare, infection is possible. After the injection, be aware of increased swelling, heat, and pain.
- Prices vary. Costs for both hocks will vary depending on where you live, how many sites you need injections and what you pay.
- Recurrent corticosteroid injections have been shown to cause progressive joint damage. There is less risk with certain steroids than others, and it is lower in low-motion joints such as the lower hock than high-motion joints such as the stifle. However, this is something to be aware of. Horses that have received only one injection are unlikely to experience a problem. However, horses who receive multiple injections every few months may be at risk.
- Injections do not prevent DJD, but there is no evidence. It is sensible to inject horses with a problem. If he does not have a problem, it may be more dangerous.
IRAP therapy: IRAP injections are an option for horses who have not responded to traditional joint injections. The initials of IRAP therapy are interleukin-1 antagonist protein. This substance is derived from horse blood. IRAP targets interleukin-1, an inflammatory substance that plays a critical role in the destruction of cartilage. Although the therapy is new, it is now available in a growing number clinics. These are the basics.
- A special syringe with glass beads is used by the veterinarian to draw blood samples from your horse. The glass beads attract white blood cells, which then begin to produce anti-inflammatory proteins. After a 24-hour incubation, the sample is spun in the centrifuge to separate serum (the liquid portion) from the blood. Next, the serum is packed with anti-inflammatory protein and is injected into the affected joints for three to five weekly treatments.
- Side effects are very unlikely because the serum is made from horse blood.
- This treatment is not for everyone. The cost of the treatment is more expensive than traditional injections, at $1,300 per series. Although there have been some reports of success with hock treatment, it has not been proven to be effective in high-motion joints.
The Whole Horse Option
The second method involves administering medication to horses’ systems. It is hoped that the medication will travel to the joint and reduce inflammation.
Systemic injections: How about HA (Legend?) intravenously and polysulfated glycosaminoglycan, (Adequan) is injected. i.m.) into muscle. Adequan is claimed to have a protective effect upon cartilage. This makes it a good choice for those with evidence of cartilage damage. (Polysulfated Glycanoglycan, also known as PSGAG, is an important component of cartilage.
- People often combine hock injections and systemic Adequan or Legend. This is a good idea if your horse has arthritis in other joints than his hocks. The systemic product might also help these joints. Injecting the joints directly is the best option if the problem is limited to the hocks.
- There are many responses. There are a variety of responses. Some horses respond better to Adequan while others prefer Legend. Others may do better with a combination of both.
- Shots are generally given on an ongoing basis at intervals of six to seven weeks depending on the horse’s needs.
- These medications are not associated with any particular dangers. Although they are not prescribed as preventive medications, they are often used with this in mind.
- Adequan is listed at $70 per dose, while Legend costs about twice as much (not including administration costs). You can save significant money by ordering from a mail-order provider if you have a prescription from your veterinarian.
Nutraceuticals: There are dozens of non-prescription liquid, powdered and pelleted joint supplements. Many of these supplements contain chondroitin and/or glucose, which are believed to be building blocks for cartilage. Other ingredients include hydrolyzed collagen (a processed form of collagen, the protein that forms the framework of bone and cartilage), oral HA, methylsulfonylmethane (MSM contains sulfur; sulfur bonds are essential structural features in all connective tissues), omega fatty acids and more. These are some of the things to keep in mind as you shop.
- DJD can’t be solved by a supplement. These products can be used as adjuncts or preventives for joint problems in the early stages of DJD. They won’t cause any harm.
- It is not clear from the research which ingredients are most beneficial for horses and in what amounts. A combination of chondroitin and glucosamine (Cosequin) has been shown to be effective in some cases. It was found to protect the joints from degenerative injury. Recent research at Colorado State found that soybean unsaponifiables and avocado, which are small amounts of oils from these plants, slow down the breakdown of cartilage in horses. Other ingredients are still being researched.
- These products are not required to comply with licensing standards, unlike drugs. Therefore, manufacturers don’t need to conduct clinical trials to prove that their products are effective. Furthermore, no agency enforces product quality standards. The National Animal Supplement Council seals products as voluntary commitments to quality control standards.
- You can expect to pay anywhere from $20 to $80 per month for horse care.
To use his leg, your horse doesn’t really need his distal hip joints. The DJD process is advancing, and the bones may fuse naturally. This can make your horse more comfortable.
In extreme cases, it may be possible to fuse the affected joint. To stimulate bone growth, there are a variety of techniques available, including surgical procedures and injections of irritants. Each option has its pros and cons. Talk to your veterinarian about the possibilities.
Fusion is not a panacea. Fusion is a treatment that can improve the health of 60 to 80 percent. It may be more sensible to consider rethinking your career if your horse is no longer able to tolerate joint injections or other treatments. He might still be able to do light work or be ready for retirement.
Gary M. Baxter is a professor of surgery at Colorado State University’s College of Veterinary Medicine. He holds the VMD, MS and DACVS designations. His interests include lameness, performance-horse injury, development bone diseases in young horses, and treatment for arthritis.