b'areas of the navicular bone. He or she scrutinizes the images for bone surface abnormalities, the distinction betweenDeep Digitalthe outer cortex and inner medulla, andFlexor Tendonbony remodeling and lysis (bone loss).(DDFT)The vet also carefully analyzes the inter-face between the DDFT and the flexor surface of the navicular bone for lesions.Short Pastern BoneIf youre thinking, I thought ultra-sound was the best way to visualize ten- Coffin Bone Navicular Bonedons, youre right! However, due to the tendons close association with the navicu- Navicular Bursalar bursa, lesions and calcifications on the(between the bonetendon can be visible onradiographs. and DDFT)Some horses with caudal heel pain have few to no visible changes on radio-THE HORSE STAFFgraphs. These horses might warrant aDigital Cushionmore intensive diagnostic plan. While ultrasound is a great tool for looking at tendon and ligament injuries, it can be difficult to see the tissues of the navicularThere are a variety of mechanisms wehoof wall or sole we have at our disposal apparatus due to the horses lower limbcan use to compensate for what cannotfor the initial trim (as well as other) bony anatomy and ultrasounds limited abilitybe achieved with the trim, says Lordan.pathology (disease or damage) which may to penetrate the hoof wall. ResearchersA negative palmar angle can be ad- need further consideration, says Lordan. have found that MRI is incredibly helpfuldressed with wedges or with a rocker- Radiographs give your farrier another for definitively diagnosing podotrochlosisstyle shoe, and optimal breakover can bewindow into the foot to use as a guide.in horses. It provides the best and mostbuilt into the shoe itself. complete imaging method for the equineFarriers also commonly add heel wedg- Oral Medications hoof.es to help navicular horses. The elevation,Non-steroidal anti-inflammatory drugs, in theory, relieves DDFT pressure on theor NSAIDs, are popular treatments for Trimming and Shoeingnavicular bone, which in itself can causeconfirmed cases of podotrochlosis. Phen-Your farrier is the frontline against theheel pain. While wedges are popular withylbutazone (Bute) and firocoxib (Equioxx) war on podotrochlosis. Usually, correctiveveterinarians and farriers alike, not allare two potent NSAIDs commonly used to trimming and shoeing is the first therapyhorses respond well to them, causingdecrease inflammation caused by the con-we attempt when managing horses withfurther frustration for all involved.dition. Usage of NSAIDs does come with the condition. For this treatment to beTalented farriers can look at a hoof andrisks, however, including gastrointestinal successful, your veterinarian and farrierestimate whats going on inside, but theulceration and kidney damage, so talk to must work as a team to come up with theonly way to definitively see the structuresyour veterinarian before administering. best plan for your horse.is with X rays. Radiographs will giveFirocoxib has gained popularity because There are several conformation typesus the palmar angle, hoof-pastern axisits proven to be gentler on the horses that can experience heel pain, says Betsy(alignment of the hoof with the pasterngastrointestinal tract than Bute. Lordan, DVM, CJF, of SRH Veterinaryangle), and help us determine how much Services, in Ipswich, Massachusetts. Bisphosphonates Veterinarians commonly see long-toed,Available in Europe for years, bisphos-low-heeled horses with these issues. Thatphonates are a relatively new drug in toe acts like a lever arm and puts addedNorth America. After FDA approval in stress on the navicular apparatus and the2014, these drugs have gained a place other soft tissue structures in the backin the navicular toolbox. As opposed to half of the foot, Lordan says, adding thatother medicines, bisphosphonates ad-shortening the toe can make a world ofdress podotrochlosis at a cellular level. difference for these horses.The horses navicular bone undergoes The orientation of the coffin bone itselfremodeling throughout its life, not too can be a factor in caudal heel pain. Indifferent than our own bones, says JD horses with low heels, the coffin boneConway III, DVM, of Conway Veterinary can drop backward, stressing the entireServices LLC, in Decatur, Texas. navicular apparatus. This is known asRemodeling in any bony structure is SHELLEY PAULSONa negative palmar angle (the angle thedriven by osteoclasts, cells that absorb bottom of the coffin bone makes withbone tissue naturally. Overaggressive the ground). While trims are important,osteoclasts, however, can cause problems horses suffering from podotrochlosisHeel wedges might help relieve the DDFTs pres- that lead to inappropriate bone lysis. might need proper hoofwear, as well.sure on the navicular bone. This lytic process is thought to be TheHorse.com|The HorseJanuary 202029SBS_Jan_use.indd 29 12/4/19 1:58 PM'