Improvements in diagnostics and individualized treatment can help keep this condition from being career-endingRadiographs (X rays) have been the common imaging approach to help diagnose podotrochlosis, but they lack the ability to reveal soft tissue structures that might also be affected. | Courtesy Dr. Amy RuckerPodotrochlosis, commonly known as navicular disease, remains a challenging condition, but what was once a dreaded career-ending diagnosis can now be diagnosed and treated with improving success.The biggest step forward in recent years involves a deeper understanding of navicular disease in horses. This outdated term lacks context without further clarification, says Ben Flakoll, DVM, an associate veterinarian and podiatry team member at Rood & Riddle Equine Hospitals Saratoga, New York, location.When someone tells me their horse has navicular or was diagnosed with navicular syndrome, that tells me the horse probably had caudal (toward the rear) heel pain that resolved after a palmar (digital nerve) block, he says, referring to injection of a local anesthetic over these nerves in the low pastern area of one limb. The problem with this is that there are a lot of structures in the heel that can cause pain.Previously, the industry used navicular as a catchall term to describe pain in the horses foot. As diagnostics have advanced, veterinarians have been able to assess the inside of the hoof more accurately.Over the longer term, shifting the focus from just degenerative processes and remodeling of the bone itself to more of a complex of processes, injuries, and soft tissue structures in the heel region has been the biggest shift in understanding heel pain, says Megan Williams, DVM, Dipl. ACVS, assistant professor of equine surgery at Oklahoma State University, in Stillwater.Todays understanding of podotrochlosis, a term that accurately captures the complexity of the condition, offers new opportunities for successful management and a return to work based on the severity of a case and the response to treatment.As the definition of the condition has evolved, so too have the approaches to confirming it. Diagnostic technologies once limited to assessing bone now reveal the complex interplay of soft tissue and joint structures within the hoof.Diagnostics for PodotrochlosisAdvances in imaging, specifically MRI technology and positron emission tomography (PET) imaging scans, now allow veterinarians to identify the specific source of pain, whether in the navicular bone, deep digital flexor tendon (DDFT), bursa (the fluid-filled sac between the bone and the DDFT), or other soft tissue structures. Previously, diagnostics were limited to radiographs (X rays) and ultrasound.One problem with X rays is that there are a lot of soft tissue structures within the heel that even if theyre damaged, you wont see on an X ray, Flakoll says. The other problem is the horse has to have lost about 40% of the bone density before you see an issue on the X ray.In other words, catching degeneration in the horses navicular bone on an X ray means missing changes in the surrounding soft tissues or lesions until advanced remodeling has occurred. Access to MRI technology now allows equine veterinarians to pinpoint the exact problem, whether thats a navicular bone lesion, inflammation in the bursa or the DDFT, coffin joint inflammation or arthritis, or desmitis (inflammation in the ligaments holding the navicular bone in place, which include the distal sesamoidean, impar, or collateral sesamoidean ligaments of the horse).While MRIs reveal a more accuratepicture of each structure than X ray, PET scans can pick up even more subtle changes. Catching those and intervening early can help prevent further damage to the bone and/or the soft tissue structures associated with the navicular apparatus.An overlay of CT and PET scans shows a severe lesion on the left navicular bone (top row) and an early one on the right (bottom row) not seen on CT. | Courtesy Dr. Mathieu Spriet, UC DavisA PET scan allows you to see biological function within, so basically youre assessing uptake of a radioactive marker, and that can let you know whether there is increased activity in a certain area, says Flakoll.A PET scan provides information about changes happening at a molecular level, so you can sometimes start seeing increased biological activity before structural changes can be seen with a CT or MRI, he explains.Not only is it telling you where theres a lesion, it can also tell you where there could be a lesion in the future, he says. The other thing thats useful is that some cases have multiple lesions that might require different therapeutic approaches. Using a PET scanner in these cases lets you figure which of the lesions is biologically active and most likely to be the source of the lameness, which allows for a more targeted therapeutic approach.Downsides to PET include cost and limited availability, with only a handful of units in the United States.Foot Preparation and PlacementWhile advanced imaging technologies such as MRI and PET scans provide more detailed insights into heel structures, X rays remain a fundamental tool in the diagnostic process. Widely accessible and affordable, they allow veterinarians to spot lesions, including arthritis surrounding the coffin and pastern joints, enthesopathies (injuries or disease where tendons/ligaments attach to bone), synovial invaginations (holes that fill with joint fluid) in navicular bones, and a lucent region in the bones flexor cortex (the surface the DDFT glides over).However, Ty Corbiell, DVM, owner of Cor Veterinary Services, in Alberta, Canada, notes foot preparation and placement play a crucial role in imaging accuracy, particularly for X rays. Cleaning the hoof, trimming, and sometimes packing is worth the extra time it takes to prep the foot, he says, and key to getting proper images.At the upcoming 2025 AAEP Annual Convention, to be held Dec. 6-10 in Denver, Colorado, Corbiell will present The Right AnglePositioning Tips for Navicular Radiography, in a burst session.The skyline radiographic view of the navicular bone (the palmaroproximal-palmarodistal oblique) is traditionally taken at a 45-degree angle with the limb pulled caudally, Corbiell says. Instead of taking just one image at 45 degrees, it has been documented that taking multiple views for the skyline positioning at a more shallow angle and a steeper angle can be beneficial in detecting lesions on the flexor cortex of the navicular bone.Other techniques Corbiell says provide more information and result in more consistent images are maintaining consistent distance from the generator to the X ray plate for all views, properly sized foot blocks based on the specific generator being used, and accurate generator settings to ensure optimal exposure. Combining X ray and ultrasound in a field setting can be very informative, he adds.All of these seem simple enough but cant be underestimated, so its important to build in time to take images at all of these angles, he says. Partnerships with board-certified radiologists, farriers, physiotherapists, and other veterinarians to build a network to share images, ask questions, and refine our approach together are important.A Shift Away From SurgeryWith a better understanding of the complexity of podotrochlosis, equine practitioners are moving away from the once-recommended surgeries (including neurectomy to block heel sensation, adhesion removal, and ligament cutting). The shift comes from evidence showing certain horses face higher risks of catastrophic outcomes should they lose pain sensation, Williams says.Im much, much less likely to recommend neuroectomy, she adds. The unfortunate reality is the majority of horses that wind up being neurectomized for navicular disease are not the best candidates. When you take horses with severe degenerative changes or soft tissue pathology and make it so they can no longer feel their foot, theyre much more likely to fracture their navicular bone or rupture the deep digital flexor tendon. Thats a life-ending complication those horses shouldnt have to go through.Other surgical approaches, such as navicular bursoscopy, in which veterinarians use an endoscope to diagnose and treat adhesions in the navicular bursa, have also waned in popularity due to variable success rates, cost, and alternative options, Williams adds.Therapeutic Shoeing ImportantProper trimming and therapeutic shoeing have long formed the foundation of managing horses with heel pain. Horseshoeing practices that prioritize proper hoof balance, especially bringing the breakover (the point at which the heel lifts off the ground during movement) back appropriately and supporting the heels, are crucial.The low heel and long toe hoof conformation is still such a common problem, Williams says.Flakoll lists the three main goals farriers should achieve when shoeing podotrochlosis horses: Increase palmar angle, facilitate breakover, and help with concussion.A proper trim sets the foundation; without it, the shoeing package will not succeed.No single best shoe exists for every horse; the right shoe depends on the horse, how much change needs to occur in the foot, and the shoes a farrier is comfortable setting.No shoeing package is perfect, and the therapeutic needs of a horse need to be balanced against athletic performance, Flakoll says. Knowing the exact nature of a lesion is incredibly important for your veterinarian and farrier and allows for much more targeted therapeutic approaches.The Role of MedicationsFor some horses, therapeutic shoeing alone resolves lameness and allows a return to work. For more severe cases, additional interventions, such as injections of bisphosphonates or orthobiologics, might be needed, but preferences and opinions vary on their use.The problem with these medical interventions theyre not benign, Flakoll says. Whenever you can get away with just the shoeing, that is the ideal scenario.However, he adds that if he cant get a horse sound with shoeing alone, he often adds orthobiologics. Which approach he uses depends on the individual case because sometimes the structure affected cant be injected. If it can be injected, orthobiologics can be a good adjunct therapy, he says.Willams adds, If you ask 100 different veterinarians, you might get 100 different answers as far as which products they prefer and when they would use them.In the horse population Corbiell works with, a number of horses have DDFT injuriesand navicular bone injuries.Patients that have injuries to the supporting soft tissue structures of the navicular bone and/or DDFT injuries have an increased chance of healing with the use of orthobiologics, in my opinion, he says. The method of delivery depends not only on the specific type and location of injury for each case but also the specific treatmentproduct being used.Delivery of the orthobiologiccan be difficult depending on the specific injury, so Corbiell says he prefers to ultrasound-guide navicular bursa injections to avoid needle penetration of the DDFT. His practice also uses ultrasound to guide orthobiologics into tendons and ligaments if the lesion can be seen without the hoof capsule impinging the view.For others, they place the therapy in the coffin joint, navicular bursa, or digital flexor tendon sheath, or they make use of regional limb perfusions, which he says helps them deliver a higher concentration of the treatment into the surrounding tissues.Our practice also uses shock wave therapy and class IV laser therapy to help stimulate certain orthobiologics to activate, to help with deeper bone pain, soft tissue enthesopathies, and to stimulate neovascularization as well, he adds.A Look AheadPodotrochlosis has no cure, but advances in imaging, individualized treatment protocols, and farrier-veterinarian collaboration now give many horses a chance to stay sound and in work.This condition isnt a death sentence for a horse anymore, Williams says. We still cant cure it, but we can do more than ever to manage it and keep horses comfortable and performing for longer.Further research will be key to refining treatment and improving outcomes.