Lecture 6 - Disorders of the Equine Foot

Physical exam focus for equine foot

Color, odor, consistency changes; clean sole; flex/extend; hoof testers; observe gait

Hoof shape/balance assessment

Evaluate trimming/shoeing quality, hoof wear, symmetry

Significance of hoof cracks

Clinically significant if deep, painful, or involving sensitive tissues

Digital pulse significance

Increased or bounding pulse indicates inflammation or pain in foot

Hoof tester use

Localizes pain; test toe, quarters, heels, frog

Diagnostics for foot disorders

Nerve blocks, radiographs, contrast studies, scintigraphy, CT, MRI

Thrush definition

Infection of frog

White line disease definition

Infection of white line; "seedy toe"

Thrush/white line disease etiology

Moisture, poor hygiene, poor hoof care, reduced weight bearing, immunocompromise

Thrush/white line disease organisms

Mixed infections: aerobic, fungal, anaerobic (Fusobacterium necrophorum)

Thrush/white line disease clinical signs

Foul smell; hoof abnormalities; lameness only in severe cases

White line disease radiographs

Determine extent of infection

Thrush/white line disease treatment

Improve hygiene; debride tissue; hoof wall resection (white line); copper naphthenate; iodine

Canker definition

Chronic inflammation/proliferation of sensitive lamina; resembles granulation tissue

Canker signalment

Common in draft horses; can affect any breed

Canker etiology

Unknown; possibly anaerobic bacteria

Canker clinical signs

Soft, greasy, friable proliferative frog tissue; yeasty smell; mild lameness; multiple hooves affected

Canker treatment

Extensive surgical debridement; local antibiotics (metronidazole); antifungals; corticosteroids; liquid nitrogen; long-term care

Subsolar bruising etiology

Thin soles; wet conditions; rocky ground

Corn definition

Sole bruise at angle of sole; often due to overdue shoeing

Subsolar bruising diagnosis

Variable lameness; worse on rocky ground; diffuse hoof tester pain; squishy sole

Subsolar bruising treatment

Poultices; shoes; keep out of mud

Subsolar abscess definition

Infection under sole causing severe pain

Subsolar abscess etiology

Wet conditions; keratoma; chronic abscess; bruise; puncture wound; nail issues; bacterial entry

Subsolar abscess clinical signs

Acute severe lameness; increased digital pulse; distal limb swelling; squishy coronet; strong hoof tester response

Subsolar abscess drainage

May break at coronet or heel; still need ventral drainage

Subsolar abscess diagnosis

Acute severe lameness; fracture ddx; radiographs sometimes helpful

Subsolar abscess treatment

Pain relief; tetanus toxoid; pare abscess; soak in Epsom salts; poultice; protect foot; shoe after resolution

Poultice purposes

Reduce inflammation; hyperosmotic effect; harden hoof

Poultice materials

Sugar; Epsom salts; DMSO; clay; Animalintex; iodine; Keratex

Hoof wall defects: distal cracks

Usually superficial; not typically lame unless deep

Hoof wall defects: proximal cracks

Coronary band trauma; often painful

Floating crack technique

Reduce weight bearing/shear on heel/quarter cracks

Notching crack technique

Prevent propagation; used at toe

Heel crack management

Dremel crack; float heel

Hoof wall stabilization methods

Patches; wires; screws; acrylics

Penetrating sole wounds rule

Do NOT remove object until after radiographs

Penetrating wound imaging

Radiographs; contrast if object removed prematurely

Penetrating wound synovial involvement

Treat as septic arthritis; refer

Penetrating wound treatment

Aggressive antimicrobials; local therapy; RLP; NSAIDs; tetanus; clean tract

Surgical options for penetrating wounds

Street nail procedure; navicular bursoscopy; flexor tendon tenoscopy; coffin joint arthroscopy

Street nail procedure aftercare

Sterile bandages; hospital plate; lavage; antimicrobials; NSAIDs; guarded prognosis

P3 fracture clinical signs

Acute moderate-severe lameness; hoof tester sensitivity; increased digital pulse

P3 fracture types

I: abaxial non-articular; II: abaxial articular; III: axial articular; IV: extensor process; V: comminuted; VI: solar margin

P3 fracture diagnosis

Radiographs; repeat in 7-10 days; obliques; coffin joint arthrocentesis; CT/MRI

P3 fracture treatment (I-III)

NSAIDs; stall rest 2-4 months; hoof capsule stabilization (cast, rim shoe)

P3 fracture type III treatment

Possible internal fixation; high complication rate

P3 fracture healing

May never form bony union; horse can be sound despite unchanged radiographs

P3 fracture type IV treatment

Arthroscopic/arthrotomy removal; buttress foot

P3 fracture type V prognosis

Poor; euthanasia recommended

P3 fracture type VI treatment

Remove only if septic; most heal; fragments resorb

P3 fracture prognosis: type I-II

Good to fair; depends on joint involvement

P3 fracture prognosis: type III

Fair; depends on reduction quality and coffin OA

P3 fracture prognosis: type IV

Good; depends on coffin OA; may be incidental

P3 fracture prognosis: type V

Guarded for life

P3 fracture prognosis: type VI

Good

Keratoma definition

Abnormal hoof wall thickening; epidermal tumor-like; secondary to inflammation/trauma

Keratoma clinical signs

P3 distortion; recurrent abscesses; lameness

Keratoma treatment

Surgical removal; better prognosis than conservative management

Quittor definition

Infection of collateral cartilage; chronic draining tract

Quittor etiology

Laceration or penetrating trauma

Quittor treatment

Surgical debridement; risk of entering coffin joint

Pedal osteitis etiology

Concussive trauma; septic process from abscess

Pedal osteitis diagnosis

Moderate lameness; hoof tester sensitivity; radiographs

Pedal osteitis treatment

Rest; shoeing; pour-in pads; egg bar shoes; heart bar shoes

Navicular bone fracture etiology

Trauma; acute severe lameness

Navicular bone fracture diagnosis

Radiographs; PD nerve block

Navicular bone fracture treatment

Conservative shoeing with raised heel; surgery not recommended

Bipartite navicular bone

Congenital anomaly; NOT a fracture; important to recognize