First of all: There is no miracle cure for navicular inflammation! The treatment process is long lasting and can only be achieved through consistent measures in hoof trimming, horse keeping and equestrian use / training.
The ailment known as “navicular syndrome” is actually called podotrochlosis and continues to raise concerns, particularly within the realms of dressage, western riding, and other sport-related equestrian activities. It appears to be more prevalent in these disciplines compared to, for example, leisure horses.
This condition impacts the navicular apparatus nestled within the hoof capsule. Comprising the deep flexor tendon, the navicular bone, and the navicular bursa, this intricate mechanism collaborates with the navicular bone to facilitate smooth movement of the deep flexor tendon across the hoof joint.
Inflammation within this area isn’t solely agonizing, but it also induces a noticeable alteration in the horse’s gait and conspicuous changes in their resting stance.
While standing and resting, it’s noticeable that affected horses often exhibit a distinctive behaviour of intermittently extending one leg forward. This action is taken to alleviate discomfort by relieving pressure from the deep flexor tendon. It’s important to distinguish this from the usual staggered posture horses adopt during grazing. This relieving behaviour is commonly observed when horses are standing or dozing in the paddock. In this scenario, one leg is consistently advanced and remains unburdened, while the other leg carries the horse’s weight.
Alternatively, some horses assume a parallel stance at rest, albeit with their carpal joints slightly flexed. This posture similarly relieves pressure from the deep flexor tendon. In motion, these horses frequently exhibit shortened steps and seem reluctant to bear full weight on the ball of their foot. This is in contrast to laminitis cases, where horses typically avoid placing weight on their toes.
Navicular inflammation generally affects both sides legs, with a higher occurrence in the front legs. However, it’s not uncommon, albeit often misdiagnosed, for it to manifest in the hind legs as well. In the front, one leg is usually more affected than the other, usually the supporting leg.
For diagnostic purposes, an X-ray of the navicular bone is typically conducted. Regrettably, research has demonstrated a lack of direct correlation between X-ray results and clinical observations. This implies that a horse could exhibit alarming X-ray indications yet remain free of lameness and capable of performing its tasks throughout its life.
Conversely, numerous instances exist where X-rays show no significant anomalies, but the horse displays evident lameness and clinical indications of navicular inflammation. Since X-rays solely depict bone density and not inflammation in soft tissue, a comprehensive diagnosis must always encompass clinical observations.
Navicular syndrome can stem from various causes. Nonetheless, incorrect hoof trimming and improper load distribution from riders emerge as primary triggers. Addressing these factors forms the foundation of therapeutic interventions.
Some farriers still opt for using wedge irons on horses with navicular issues, but this practice is notably erroneous. As far back as the 1970s, studies highlighted the detrimental effects of this approach: the hoof’s blood supply diminishes. Essentially, the horses experience a sensation akin to feet falling asleep. This leads to a deceptive appearance of lameness-freedom, as the horses no longer feel pain. However, the inflammation persists, and the compromised blood circulation inhibits effective healing.
This compromised approach often culminates in a recurrence of lameness a few years post the initial episode. By this juncture, the chronic inflammatory process has frequently affected or even destroyed additional regions. Similarly, the practice of performing nerve cuts follows a comparable trajectory: pain perception is stifled, and lameness dissipates. The horse resumes bearing weight, only to encounter renewed lameness a few years later when the nerve regenerates. This time, however, the destruction within the hoof area might be even more advanced due to the intervening years of compromised health.
Instead of resorting to expensive shoes, opting for a barefoot approach often proves more logical in many cases. Allowing the horse to go barefoot enables the natural hoof mechanism to function normally again. Subsequently, giving the horse a restorative period of 6-12 months on a pasture or paddock is highly beneficial (while adhering to regular barefoot trimming intervals). When removing the specialised shoes that may have been previously used, it’s common for the horse to experience a pronounced lameness initially. Throughout this phase, it’s essential to avoid administering potent painkillers, or if necessary, do so with cautious dosages. Pain, after all, serves as a vital bodily signal against overexertion.
During this regenerative period, it’s recommended that the horse moves independently and of its own accord. This means refraining from integrating it into the herd during this phase or any similar activities. An optimal approach is to offer a fenced meadow within view of other horses or with a calm, friendly companion horse. It’s advisable to avoid utilising stony, asphalt, or gravel paths. If feasible, situate shelter within the meadow or, if a paved area exists, furnish it with sand or wood chips.
Over the span of approximately 3 months, a notable improvement in gait typically transpires, often mitigating acute lameness. Within about 6 months, the lameness completely disappears in most instances.
However, to prevent regression, it’s imperative not to commence training prematurely. In the long run, these horses frequently experience enhanced well-being when housed in an open yard or track system compared to being stabled, as unrestricted movement bolsters hoof circulation.
The root causes within the equestrian sphere often stem from a tendency towards “excessive and hasty”. This pattern is particularly evident in western riding, where early training initiation—sometimes as early as 2-3 years old—is deemed “routine”. Similarly, the practice of initiating training in dressage horses is increasingly observed at younger ages to accommodate performance goals.
Back in the day, training towards the medium level wasn’t embarked upon until a horse reached 6-8 years of age. In modern times, it’s not uncommon to witness horses at this age range executing advanced manoeuvres. This trend even affects traditionally late-developing breeds like Icelandic horses, which are increasingly being introduced to saddles at 3-4 years of age, as opposed to the earlier norm of 6-7 years.
However, nature’s course cannot be manipulated at will. Regardless of whether it’s a pony or a warmblood, every horse undergoes bony growth in height until around 6 years old. Subsequently, for the following two years, growth primarily manifests in width, marked by substantial muscle mass accumulation until the age of 8. By the time a horse reaches its 8th to 9th year, its natural development is essentially “complete”.
The final epiphysis, or growth plate, takes shape between the 5th and 6th year of a horse’s life. The last of these occurs in the sacrum, a bone that shapes the rear portion of the spine preceding the initiation of tail vertebrae.
Most of the muscles necessary for a horse to collect itself and bear weight with its hindquarters attach to this sacrum. As long as the sacrum hasn’t fully ossified, a horse anatomically remains incapable of effectively bearing weight with its hindquarters, resulting in automatic weight distribution toward the forehand. If exercises are demanded that necessitate hindquarters engagement before the sacrum is completely ossified, these horses essentially “cheat” by relying on muscle tension to navigate through such exercises.
It’s no coincidence that impeccably executed piaffes are rarely witnessed today. The walk in many horses has shifted towards a pacing gait. Icelandic horses, in particular, grapple with profound back issues, to the point where some struggle to even trot, instead being promoted as “natural tölters”.
In western horses, you also have the problem of being burdened by the weight of a rider at a much too young age. These horses are often relatively small and delicate compared to their riders, particularly when they start working the saddle at the age of 2 to 2.5 years. The combined weight of the rider and their saddle frequently prompts the closure of growth plates on the front legs, particularly those along the front cannon bones, prematurely.
Subsequently, the horse’s growth primarily progresses in the hindquarters, with restricted advancement in the forequarters. This imbalance arises from the elongation of the cannon bone, which undergoes the most pronounced lengthening in this region and concurrently bears the brunt of the load during movement that emphasises the forehand. Consequently, horses ultimately mature with a downhill build, characterised by a croup that stands taller than the withers.
A horse with such a conformation encounters heightened challenges in bearing weight with its hindquarters, exacerbating its predisposition for forehand predominance. Furthermore, horses initiated into training at such a premature stage acquire incorrect movement patterns as a means to compensate for the deficient hindquarters engagement. Rectifying these patterns requires significantly more time and effort compared to instilling proper training techniques later on.
The aftermath of excessively early training initiation and particularly premature performance demands frequently manifests as an excessive burden on the forehand’s structures, which can precipitate chronic issues with navicular syndrome.
The trend of early retirement in sport horses holds significance for a reason – western horses frequently bow out between 6 and 8 years of age, a time when they should ideally just be reaching full maturity and embarking on their careers. Even in disciplines like dressage and show jumping, spotting a horse over the age of 10 performing at a high level is increasingly rare.
This training approach affects Icelandic horses as well, potentially curtailing their longevity, and in some instances, they don’t reach the legendary age typical of their breed. Instead, they prematurely display signs of wear and tear due to training that starts too early and often neglects proper activation of their backs. Navicular issues are more prevalent in these early-started, demanding training regimens.
Each additional year given to a horse for growth and development in its formative years reaps rewards in the form of a healthier musculoskeletal system and an extended period of performance capability.
