b'STEP BY STEP CHRIS WHITE, DVMTheHorse.com/Step-By-StepPodotrochlosis 101The trials and frustrations of navicular diseaseClinical Signs The manifestations of caudal heel pain arent black and white. Horses with podo-trochlosis display any number of clinical signs, which can make coming up with a diagnosis and treatment plan a long, chal-lenging battle. The lameness most often affects horses around the ages of 7 to 9, though it can appear in equids of any age. The horse often starts showing signs of lameness after a period of rest and reintroduc-tion to work. Early in the disease, some horses work out of the lameness after a proper warmup. The degree of lameness Magnetic resonance imagingmight vary from day to day, which can be provides the best and mostincredibly frustrating for owners and vets. KEVIN THOMPSON/THE HORSEcomplete imaging methodHorses with navicular-related lame-of the equine hoof and,ness often display a very short-strided or therefore, the best chancechoppy trot. They tend to stumble at for a definitive diagnosis of navicular disease. a trot or even a walk and have a visible head bob correlating with one of the forelimbs. The lameness usually worsens P odotrochlosis. Navicular disease.tendon (DDFT). One side of the navicu- if the horse is forced to circle or trot on a Caudal heel pain. A rose by anylar bone (the flexor surface) borders thehard surface (concrete or driveways are other name would be asfrustrat- DDFT. The navicular bursa buffers theideal for lameness workups). ing? Though it goes by several names, thecontact between the two structures toThe disease usually affects both condition is common among horses andprevent adhesions from forming betweenforelimbs, though one forelimb might frustrating for owners, farriers, and vet- the navicular bone and the DDFT.be worse than the other. Nerve blocks erinarians alike. It takes a team to trulyThe role of the soft tissue structures(by which veterinarians desensitize the address and treat the underlying cause ofsurrounding the navicular bone is to sup- navicular apparatus) of the lame foot a horses navicular-related lameness.port the bone while the animal is stand- often reveal lameness in the seemingly ing and moving, says Tammy Muirhead,good leg. Navicular Apparatus Anatomy DVM, professor of anatomy at the Atlan-Thirty years ago veterinarians believedtic Veterinary College, on Canadas PrinceDiagnosis any horse with navicular disease mustEdward Island. If one or more of theseVeterinarians can use several tech-have degeneration of the navicular bone.structures are affected, excessive strainniques to definitively diagnose podo-Decades of research and education later,can be placed on the (navicular) bone,trochlosis in horses. However, many we know the lameness associated with theleading to degeneration or remodeling.navicular disease diagnoses are based condition might not be solely the navicu- Equine practitioners classify the result- on clinical signs alone due to lack of lar bones fault. Rather, many structuresing lameness from the bone or any of thepractitioner experience, availability of work in sync as the navicular apparatus.soft tissue structures as podotrochlosis,diagnostic equipment, or owner finances. This includes the navicular bone, the na- because the condition can involve anyThe most common imaging modality vicular bursa, the coffin joint, the imparpart of the podotrochlear apparatus: theused to diagnose the condition is radiog-ligament, the suspensory ligaments of thenavicular bone, DDFT, navicular bursa,raphy. The veterinarian takes a series of X navicular bone, and the deep digital flexorand supporting ligaments. rays to get a detailed look at the affected 28January 2020The Horse|TheHorse.comSBS_Jan_use.indd 28 12/4/19 1:58 PM'