Lecture 9 - Common Disorders of the Equine Fore Limb

Prognosis categories

Excellent >90%; Good >75%; Fair >40%; Guarded/Poor

Most common region causing forelimb lameness

Foot

Least common region causing forelimb lameness

Above carpus

P2 fracture types

Comminuted; chip; palmar process

P2 fracture etiology

Trauma; twist injury; western performance; pasture accident

P2 fracture clinical signs

Fracture lame; acute severe lameness

P2 fracture diagnosis

Radiographs

P2 fracture treatment

Internal fixation + pastern arthrodesis; half‑limb cast; transfixation pin cast

P2 fracture prognosis

Fair-good; decreases if coffin joint involved

Pastern joint OA name

High ringbone

Pastern OA etiology

Conformation; trauma; sesamoidean ligament injury; OC cysts

Pastern OA clinical signs

Moderate lameness; bony swelling; positive lower limb flexion

Pastern OA diagnosis

Abaxial block; radiographs

Pastern OA treatment

IA corticosteroids; arthrodesis; facilitated ankylosis (ethyl alcohol)

Pastern OA prognosis

Fair-good; second best behind distal hock OA

Fetlock OA etiology

Athletic use; conformation; trauma

Fetlock OA clinical signs

Lameness; positive flexion; decreased ROM; effusion

Fetlock OA diagnosis

Block fetlock or low 4‑point; radiographs

Fetlock OA treatment

OA protocol; arthrodesis if severe (pasture sound only)

Fetlock OA prognosis

Depends on severity; high‑motion joint cannot fuse and remain sound

Fetlock osteochondral fragment location

Dorsal forelimbs

Fetlock fragment etiology

Trauma; jumping; racing

Fetlock OCD sites

Proximal P1; mid‑sagittal ridge of MC3

Fetlock fragment clinical signs

Mild-moderate lameness; effusion; positive flexion

Fetlock fragment diagnosis

Radiographs

Fetlock fragment treatment

Arthroscopic removal

Fetlock fragment prognosis

Good-excellent

Splint bone exostosis etiology

Trauma (medial most common); conformation (bench knee; toe‑out → winging in → interference)

Splint bone exostosis clinical signs

Swelling; palpation findings; +/- lameness

Splint bone exostosis diagnosis

Radiographs; ultrasound/CT if suspensory involvement

Splint bone exostosis treatment

Benign neglect; rest; NSAIDs; remove splint if suspensory interference

Splint bone exostosis prognosis

Excellent

Bucked shins definition

Dorsal MC3 periostitis

Bucked shins etiology

Racehorses early training (2 yo); remodeling response; can progress to saucer fractures

Bucked shins clinical signs

Acute lameness; short stride; worse after hard work; dorsal swelling; pain on palpation

Bucked shins diagnosis

Radiographs; nuclear scintigraphy

Bucked shins treatment

NSAIDs; rest (10-14 days mild; months severe); alter training; shockwave; osteoclast inhibitors

Bucked shins prognosis

Good-excellent

MC3 fracture etiology

Foals (pasture accident); racehorses (cumulative stress)

MC3 fracture types

Diaphyseal; palmar proximal (Standardbreds); distal condylar (TBs); Salter Harris II (foals)

MC3 fracture coaptation

Immediate and correct coaptation required

Diaphyseal fracture prognosis

Foals good; adults fair-poor

Condylars: medial vs lateral

Medial spirals; lateral does not spiral

Condylar fracture prognosis

Good for life; fair for racing

Salter Harris II location

Through metaphysis and physis

MC3 fracture treatment

Internal fixation (plates/screws); transfixation pin cast

Open MC3 fracture prognosis

Grave

Carpal disorder clinical signs

Positive flexion; reduced ROM; stiff gait; external swelling; effusion; acquired "over at knee" or "bowed legged"

Carpal chip fracture etiology

Racehorses; hyperextension at speed; early career (2-4 yo)

Carpal chip fracture clinical signs

Mild-moderate lameness; effusion

Carpal chip fracture diagnosis

Radiographs: flexed lateral + skylines

Carpal chip fracture treatment

Arthroscopy

Carpal chip fracture prognosis

Depends on cartilage/ligament damage; good if acute; poor if chronic

Carpal slab fracture etiology

Same as chips; C3 frontal plane most common

Carpal slab fracture clinical signs

Severe lameness; severe effusion

Carpal slab fracture diagnosis

Radiographs; do NOT block

Carpal slab fracture treatment

Arthroscopic-guided fixation

Carpal slab fracture prognosis

Fair-good; better in Standardbreds

Stay apparatus failure causes

Humeral fracture; radial nerve injury; olecranon fracture

Stay apparatus failure signs

Dropped elbow; cannot fix carpus; cannot extend limb

Radial nerve injury etiology

Trauma; brachial plexus avulsion; humeral fracture; prolonged recumbency

Radial nerve injury signs

Typical stance; drags limb; inconsistent sensory loss; muscle atrophy 2-4 weeks

Radial nerve injury treatment

Splint; NSAIDs; corticosteroids

Radial nerve injury prognosis

Good if recovery in 6-8 weeks; poor otherwise; risk of contralateral laminitis

Olecranon fracture etiology

Most common foal fracture; kick; open wound = bad

Olecranon fracture signs

Stay apparatus failure; swelling; crepitus

Olecranon fracture diagnosis

Radiographs

Olecranon fracture treatment

Stall rest if incomplete; surgery if displaced; tension band principle

Olecranon fracture prognosis

Good if not articular; fair if articular; guarded if open

Sports associations: racing

Carpal chips/slabs; bucked shins; condylar fractures; fetlock fragments

Sports associations: western

P2 fractures; suspensory branch injuries

Sports associations: English

Suspensory desmitis; fetlock OA; carpal injuries

Sports associations: other

Variable depending on discipline