That old horseman’s saying “no foot, no horse” never rings more true than when your favorite equine starts turning up lame too often—and for no apparent reason. When your veterinarian starts mentioning “changes” to certain bones or joints, a sinking feeling is almost sure to follow.
Once upon a time, the diagnosis of “navicular syndrome” was an automatic career-ender for many working horses. The prognosis for ringbone cases was often dire, as well.
The good news is that thanks to advances in veterinary technology and farrier science, your favorite hunter, jumper or dressage horse needn’t necessarily be retired due to these two common conditions. While not considered curable, both conditions can be managed successfully in some cases with a consistent focus on the horse’s comfort.
What Are They?
Navicular syndrome is an umbrella term for a painful condition associated with the navicular bone and/or related structures in the equine foot (such as the navicular bursa, navicular ligaments or even the deep flexor tendon—called the podotrochlea). Though the cause is generally unknown, damage to the navicular bone itself is often hypothesized to be from trauma or an interruption in the blood flow to that area. There is also some evidence that a genetic component exists in some breeds, and that heritable conformation traits might predispose an individual to development of abnormalities of the podotrochlear apparatus.
This syndrome affects one or both front feet. It causes a slow, progressive lameness that might be intermittent but which sometimes becomes more obvious and more consistent when the horse is worked on hard ground or turned in a small circle.
The term ringbone describes the bony calcification that can develop on or around the pastern and/or coffin joints when arthritis develops in the joints. This can occur due to normal wear and tear or following injury and/or inflammation. This condition can occur in any foot (or even multiple feet).
Since different factors can be involved, veterinarians stress that one cannot make broad generalizations about the changes that occur in these conditions. Every case is different.
Perhaps Stephanie S. Caston, DVM, DACVS–LA, put it best when she said that although ringbone and navicular syndrome affect different parts of the foot, “both are chronic conditions that usually get progressively worse over time.”
An associate professor of Equine Surgery at Iowa State University’s College of Veterinary Medicine, Dr. Caston has written about research on navicular issues and fusion of the pastern joint affected by ringbone. “The term ‘ringbone’ refers to the bony swelling that can occur with arthritis of either the coffin [low ringbone] or pastern [high ringbone] joints,” she explained. “Arthritis can occur in horses due to normal wear and tear but can also occur secondary to infection or a single traumatic event (e.g., an injury). When arthritis is present, there is inflammation and pain. Eventually, restricted range of motion can occur in more advanced arthritis.”
Dr. Caston went on to point out that the term navicular syndrome basically refers to lameness originating in the heel region. “It is also sometimes referred to as navicular disease or caudal heel pain,” she offered. “While problems with the navicular bone itself may be the cause of lameness in such cases, we know that there are many other structures in the region in addition to the bone that can cause lameness. Some of these are soft-tissue structures such as tendons, ligaments and the navicular bursa.”
So how are these two conditions best diagnosed? Different veterinarians sometimes have slightly differing opinions.
Craig S. Lesser, DVM, CF, is well acquainted with navicular syndrome and ringbone through his work with the Podiatry Department at Lexington, Kentucky’s Rood & Riddle Equine Hospital. “The first step [in diagnosis] is a thorough lameness exam by your veterinarian including flexions and local anesthesia,” he explained. “Depending on localization of the lameness, radiographs [X-rays] are often the first tool recruited in diagnosing these condition. However, with advances in imaging, MRIs have become the gold standard in determining the exact cause of lameness, especially in regard to navicular syndrome.”
Another veterinarian (one who also trained as a farrier) is Tracy Turner, DVM, MS, Dipl. ACVS, ACVMR, of Turner Equine Sports Medicine and Surgery in Stillwater, Minnesota. He confirmed that diagnosing either ringbone or navicular syndrome requires “careful examination of the hoof and distal limb, including flexion tests, hoof tester examination, wedge tests and nerve blocks. Typically, navicular syndrome pain is eliminated by a palmar digital nerve block, whereas ringbone requires a higher (more proximal) nerve block to eliminate or reduce the pain.
“However, imaging is where the final diagnosis will come,” he stressed, adding, “Radiography is the most important. Ringbone requires the finding of signs of arthritis of either the distal interphalangeal [coffin] joint or proximal interphalangeal [pastern] joint. Computed tomography or magnetic resonance imaging will give higher detail imaging but are not necessary to make a diagnosis. Navicular syndrome is more complex, and while radiographic changes within the navicular bone are commonly seen, they are not necessarily pathognomonic [meaning decisively characteristic or indicative of the disease].”
Like Dr. Caston, Dr. Turner was quick to note that the old term “navicular disease” was changed to “navicular syndrome” as the veterinary profession realized there were multiple factors that could cause the pain associated with the condition. “With the advent of MRI use in veterinary medicine, the soft tissues could be evaluated, which proved that this is a syndrome and pathology may be in any structure around the podotrochlea [navicular bone, bursa, joint, ligaments and deep flexor tendon],” he said.
Dr. Caston expanded upon the ways in which MRIs can be used to help both pinpoint and confirm these conditions. “Radiographs, or ‘X-rays,’ will allow diagnosis of cases of arthritis that have bony change. However, very early cases of arthritis may not yet have changes visible on the radiographs, as some structures in the joint such as cartilage, synovium and joint capsule do not show up on radiographs. In such cases, other diagnostic imaging such as MRI may be helpful in confirming the diagnosis.”
It Takes a Team
Because every case is different, there is no one-size-fits-all treatment for either navicular syndrome or ringbone. However, successful treatment and management often depend on assembling a team of professionals who will collaborate with both the horse owner and each other. As Dr. Lesser summarized, “Working with your veterinarian and farrier, a combination of medical and mechanical treatments can be initiated to ensure your athlete is comfortable for years to come.”
For his part, Dr. Turner emphasized, “Hoof care is of utmost importance in any management program. This will improve mechanics of the hoof, relieve stress on different aspects of the hoof, ease breakover, etc.” However, he added, “Anti-inflammatory therapy is necessary; this may be mild as phenylbutazone, firocoxib or other oral anti-inflammatory. It may require intra-articular injection.”
Ringbone in particular is treated most commonly “with intra-articular corticosteroids with or without hyaluronic acid,” Dr. Turner said. “But these days, there are a myriad of other intra-articular products that can be of help including IRAP, hydrogels, alpha-2 macroglobulins, etc. This would also be a good use of Adequan® to help slow the arthritis.”
In navicular syndrome management, “therapy to reduce inflammation and pain is paramount,” Dr. Turner stressed. “Bisphosphonates [Tildren, OsPhos] are useful if bone remodeling is an issue. Stem cell or PRP therapy may be necessary or helpful for tendon and ligament issues. Shockwave can be useful for some aspects. In the later stages, neurectomy (surgical cutting of the palmar digital nerve) may be necessary to control the pain.”
If this all sounds terribly technical, it’s true that modern veterinary medicine offers a dizzying array of options for addressing these conditions. However, there’s a reason treatment often centers on those tried-and-true anti-inflammatories. This is because reducing inflammation and pain can often reduce or eliminate lameness, possibly improving the horse’s movement or even allowing him to return to work. “Anti-inflammatories are often used both systemically and by injection into a joint or bursa,” Dr. Caston confirmed.
As for horses with arthritis of the pastern joint, or “high ringbone,” they can be treated by fusing the joint, Dr. Caston noted. “Fusing the joint can be accomplished with a surgery called arthrodesis that removes any remaining cartilage, then stabilizes across the joint with a plate and screws.
“Another method to promote fusion of the joint is via repeated injections with ethyl alcohol to kill remaining cartilage,” she continued. “This is called ‘facilitated ankylosis,’ and it helps speed the progression of arthritis until the joint fuses across with bone on its own. Procedures to fuse a joint can be performed in other joints, but because the pastern joint is very low-motion, the horse may function normally and return to work without lameness or gait abnormalities once the joint is fused. This is not the case for higher-motion joints.”
A Matter of Management
By this point, you may be wondering whether your equine patient is destined to be a pasture ornament or light trail mount—or whether he might safely return to competition. As you’ve probably guessed, the answer depends on various factors.
“A horse with a diagnosis of navicular syndrome or ringbone has a wide range of prognosis, depending on severity of disease,” Dr. Lesser explained. “We consistently are getting better at medically and mechanically treating the horses; however, the key to longevity is early diagnosis and intervention.”
As for whether any one discipline is more likely to cause or aggravate these conditions, it’s important to consider the individual horse and the type of physical activity being asked of him. “Every discipline has its common lameness issues, and horses with heavy concussion on the distal limb are at risk of developing either of these,” Dr. Lesser said, adding, “Poor conformation and genetics can also predispose horses to either of these conditions.”
When discussing the outlook for an affected horse, other contributing factors Dr. Turner mentioned included the extent of the pathology, the stoicism of the horse, the dedication of the owner and the quality of the farrier work. “I prefer to discuss with owners that this is a management issue,” he said. “This is teamwork between veterinarian, farrier, owner, rider, barn manager, etc. This is to constantly keep the hooves in good condition to reduce stress on the pathology, therapy to keep inflammation minimal and add any therapy to help the horse.
“In my opinion, if one of my patients with either of these conditions was turned into a pasture ornament, I would consider that a failure,” Dr. Turner continued, adding, “My goal is to return the horse to its previous level of competition. This can be a difficult task; speed [and] jumps are factors that put extra stress on the structures. Horses that perform at high levels place tremendous strain on these structures, and they require constant vigilance to continually manage issues as they occur.”
In the end, Dr. Caston underscored the fact that the prognosis for both of these conditions can vary greatly from horse to horse. “It really depends on the severity of the condition, the individual horse and the discipline,” she explained. “For example, if a horse is very lame as a result of either navicular syndrome or arthritis, it may be more difficult for the horse to be successful in the hunter show ring or in the dressage ring even if the lameness is improved with treatment.
“Conversely, if the horse is primarily used for trail riding, it may be able to function normally and have a good quality of life, even if there is a degree of lameness remaining after treatment,” Dr. Caston added.
Surfaces and Such
If your horse has been diagnosed with ringbone or navicular syndrome, you might wonder about the types of footing or surfaces on which it is safest to ride him.
At the risk of stating the obvious, it is essential to first determine (with professional assistance) whether it’s advisable to ride your horse at all—and, if so, how much. “Many horses with proper care can still be ridden at the same or a slightly lower level of competition,” Craig S. Lesser, DVM, CF, acknowledged. “But I would consult your veterinarian and farrier to determine how much work your horse can truly handle.”
Once you get the all-clear to ride, our experts advise consulting your support team about acceptable footing given your horse’s specific circumstances. “There is no single riding surface that is best or worst for horses affected by navicular syndrome or arthritis,” explained Stephanie S. Caston, DVM, DACVS–LA. “Some horses have a soft-tissue component causing the lameness. In such cases, the horses may have a harder time in softer, deeper footing. For other cases, hard ground or varied terrain may cause more pain. The best strategy is to evaluate each individual case and work with your veterinarian to determine how to best manage the horse.”
Tracy Turner, DVM, MS, Dipl. ACVS, ACVMR, concurred that there is no ideal surface for horses affected by ringbone or navicular syndrome. However, “For competition, avoid excessively hard or uneven surfaces,” he counseled. “My advice to my clients is and has always been: If you don’t like the surface, walk away from the competition.”
Jondolar’s Story: Mild to Moderate Navicular Changes
There’s a limit that conscientious horseman must respect when it comes to jumping in particular. As Shana Johnson put it, “With all jumping horses, the question in the back of one’s mind is ‘How many jumps does this horse have in him?’ One thousand, two thousand, ten thousand, maybe more?”
But, as the Scituate, Rhode Island, resident noted, “A navicular horse owner asks this question every day before riding.”
She should know. Johnson owns a 24-year-old Selle Français gelding named Jondolar de la Monteleon who was diagnosed in 2007 with mild to moderate navicular changes. Yet, despite this diagnosis, she was able to compete him successfully in the Adult Equitation 2-foot-6 division in Rhode Island and Massachusetts for many years.
Their story might sound familiar to anyone who’s owned a horse with a similar diagnosis. “I rode Jondolar for two years before purchasing him (without a pre-purchase exam),” Johnson recalled. “Two months following this date, Jondolar started with intermittent lameness. He’d be sound going straight and sometimes off on the longe line, going to the right. I brought him several times to a local veterinarian [at] Massachusetts Equine, and they finally suggested scheduling an MRI at Southshore Equine in Massachusetts. The results were mild to moderate navicular changes in his right front hoof.
“I was devastated,” she continued. “I thought this was the end of Jondolar’s jumping career at 9 years old. However, my friends talked me off the edge and advised a consultation between my veterinarian and blacksmith. X-rays were used to project the angle of the lifts/wedges that were put under Jondolar’s shoes. From here I kept a strict schedule of his shoeing every five weeks—sometimes four in the summer—in order to maintain an exact angle.”
On the veterinary side, Johnson said she addressed Jondolar’s navicular symptoms with nonsteroidals “… to help keep the blood flowing through the navicular bones.” Her regimen goes something like this: “Phenylbutazone: 1-2 grams a day around jumping lessons and pre/post horse shows. Icing and/or DMSO/MagnaPaste his front feet post competition and making sure he had plenty of turnout to keep the blood flowing, as the key to keeping him sound.
“I own a small farm, so Jondolar is outside many hours a day,” she continued. “Extremely important! He is also on Farrier’s Formula [a feed supplement] to help strengthen his feet.”
Besides veterinary assessment, corrective shoeing and appropriate medication, Johnson credits a trainer who put her horse first, keeping jumping to a minimum, for much of their success. “We were very picky about surfaces for jumping. Is the footing too hard or too muddy or too slippery?” she recalled. In addition, she said, “There have been certain times where [Jondolar] lived at home for the winter, and I would have his shoes pulled when he was not being ridden … I believe the time to rest was a good thing.”
The day finally came when Jondolar could not move up with Johnson to the 3-foot division. But, as she reflected, her horse knew his job and still had plenty to teach. “We started to look for lease options for him,” she explained. “I am very choosey; this horse owes me nothing. He can only go to a professional facility where I can trust the lessee and trainer NOT to over-jump him.”
This article originally appeared in the Fall 2021 issue of Practical Horseman.