NAVICULAR SYNDROME/PALMAR HEEL PAIN (PODOTROCHLEOSIS)

Navicular Disease or podotrochleosis encompasses a broad spectrum of conditions which affect the navicular bone and the structures around it; therefore it should be discussed as a syndrome rather than a single disease entity.

DEFINITION
Pain or soreness arising from the heel region of the foot. This syndrome is one of the most common causes of forelimb lameness in western performance horses between the ages of 4-12yrs. ( avg.6-9yrs) Quarter horse has highest incidence. Heavy, muscled horse with small feet. -Males affected more than females, geldings more than stallions. Rarely in hindlimb- except for trauma/fractures. Has been shown to be hereditary based on conformation.

ANATOMY
The navicular or distal sesmoid is a small boat shaped bone that lies behind the middle and distal phalanges. Improves the mechanics of the deep flexor tendon. Many little ligaments supporting the navicular bone.

CAUSES/ETIOLOGY
Genetics—Conformation is inherited. Large muscled horse with small feet, upright pasterns and low heels. Small feet- Increased concussion Upright pasterns- Increased concussion Poor Trimming—Leading to improper hoof angles Hard work --Calf Roping, Cutting, Barrel Racing, Gaming. Hard surfaces- Increased concussion Heavy work starting at young age

CLINICAL SIGNS
Early stages--- Intermittent, progressive lameness of a forelimb that subsides with rest. Returns with work and eventually becomes very consistent. Doesn’t occur overnight Both front feet usually involved, one foot usually more sore than the other, may go back and forth between feet. Short strided, choppy gait- Attempting to stay off the heels Pointing Hoof Testers—Sensitive over middle of the frog in 30-50%. Flexion Test – Positive in 50% Hoof Shape- Heels contract, frog tends to atrophy. Lameness worse with the affected leg to the inside of a circle. **** Lameness looks like it’s a shoulder problem. **** Not every horse that is positive to hoof testers over the frog is navicular, vise versa. Any lameness arising from the foot is NOT NAVICULAR!

DIAGNOSIS
>History- Chronic vs. Sudden onset (15yr old geld w/ acute onset probably not navicular)
>Hoof Testers
>Flexion Tests-Evaluation on firm/hard surface at trot longed. ·
>Nerve Blocks or Anesthesia
>Radiographs--- 5 views of each foot, Shoes removed important. Evidence of bone lesions in variable % of horses. Horses with lesions and no lameness Horses without lesions and lameness
>Evaluation of treatment- Injections, medication etc.
>Without History, Clinical signs, abolition of lameness with nerve blocks and radiographs, obtaining a correct diagnosis is difficult.

TREATMENT
>Shoeing is the cornerstone of treatment
>Imperative that the foot be balanced at an angle appropriate for that individual horse. >Hasten break over by shortening and rolling the toe
>Provide adequate heel support
>Reset every 5-6 weeks maximum.

MEDICATION
>Anti-Inflammatory—Bute, Aspirin, Banamine
>Isoxsuprene- Enhances blood flow Intra-articular medication-
>If Lameness is severe or coffin joint involvement- hyaluronic acid and cortisone injection.

SURGERY
Neurectomy—in end stage non-responsive cases.

 ** Legend and Adequan ** Oral Glucosamine and Chondroitan Sulfate ** Shock Wave therapy

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