Navicular Syndrome and Heel pain in the performance horse Phillip D Jones, DVM, MS Diplomate American College of Veterinary Surgeons

Outline Causes for caudal heel pain Diagnostics and therapies Shoeing recommendations

Caudal heel pain Navicular syndrome Degenerative process that changes the bone-initiation and progression of the disease is a result of excessive and prolonged forces of compression on the bone Important factors- signalment, conformation, and use

Navicular syndrome Mild to moderate intermittent lameness Insidious onset Perceived as shoulder lameness Poor confirmation Bilateral lameness Lameness switches to contralateral limb after unilateral PD block

Navicular syndrome Important PE findings -contracted heels -atrophied frog -small foot compared with body size

Navicular syndrome Medical therapy -shoeing changes -anti-inflammatory medications -rest Surgical therapy- PD neurectomy (criteria! & complications!)

Palmar Digital Nerve block -Mepivacaine: 1 -1.5ml /nerve Diagnostics Localization Palmar Digital Nerve block -Mepivacaine: 1 -1.5ml /nerve

Diagnostics

Navicular syndrome Changes within the navicular bone -edema -vascular stasis -enlargement of the nutrient foraminae -cyst-like medullary areas -subchondral bone changes -changes in the flexor surface -fragmentation of the distal border

Add normal NB

Dyson- Radiographic Interpretation of the Navicular Bone. EVE 2008

Shoeing Correct or preserve dorsopalmar and lateromedial foot balance Hoof pastern angle should be straight Foot trimmed to maintain heel mass and shorten toe to facilitate breakover Elevation of heel may relieve pressure from DDFT on palmar aspect of navicular bone Egg bar shoe: greater surface area disperses forces. -Of 55 horses with navicular disease 53% had permanent pain relief of lameness after egg bar shoes in 12-40 month follow up.

shoeing Key points: Correct and maintain dorsopalmar and lateromedial balance Ease breakover Maintain heel mass Protect palmar aspect of the hoof from concussion

Medical therapies Intra-articular injection Intra-bursal injection Tilduronic acid (Tildren) NSAID’s Isoxuprine -2.2% oral bioavailability

Treatment

Caudal Heel Pain Desmititis of the collateral ligaments. Tendonitis of the DDFT at 3 possible locations: -insertion -palmar to the navicular bone -proximal to the navicular bone Desmitis of the impar ligament. Desmitis of the distal annular ligament. Synovitis in the distal interphaleangeal joint. Synovitis in the navicular bursa. Cystic lesion in the second phalanx

Treatment

Shockwave Extracorporeal shock wave -generates a pulse wave within the body Encourages growth mediators and other cytokines integral to the healing process Offers temporary pain relief

Fracture Dyson- Radiographic Interpretation of the Navicular Bone. EVE 2008

Bipartite Navicular Bone Develops as 2 separate centers of ossification that never unite Unilateral or bilateral Broad well defined lucent line between the 2 pieces Horse may be clinically normal, or have episodic lameness in full athletic function No history of acute lameness as in fracture

Bipartite Dyson- Radiographic Interpretation of the Navicular Bone. EVE 2008

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