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!) 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 ?