Lameness – Part 2: Specific Diseases

INAG 120 – Equine Health Management

November 2, 2011

Common Lameness Disorders

FRONT LIMB Shoulder

Knee

Fetlock

Pastern

Navicular

HIND LIMB

Stifle

Hock

Fetlock

Pastern

Front Limb - Shoulder

Signs of shoulder lameness: Head lifts when limb moves forward Little flexion of limb (low foot arc)

Swinging out of limb to avoid flexion Failure to reach out (shortened

cranial phase) Fixation of shoulder joint inability

to move Hard or soft ground often has same

effect if level (may be slightly worse on soft ground)

Lameness in the Shoulder

Arthritis – Usually caused by

trauma Persistent lameness In foals, other

joints alsoinvolved

Tx: injections with steroid (usually cortisone)followed by hyaluronic acid

Lameness in the Shoulder

Sweeny – Atrophy of muscles around shoulder Paralysis of suprascapular nerve “Popping” of the

shoulder when horse walked toward examiner

Sweeny

Front Limb - Knee

Site of many developmental orthopedic diseases

Signs: Stand with knee flexed Failure to reach out in stride Lower foot arc Stiff-legged paddling gait

Carpal flexion test, joint blocks good tools for diagnosis

Front Limb - Knee

Fractures Common in race horses, jumpers,

hunters Factors = speed, immaturity,

long limb length, position of rider, distances run, firm surface

Most common is chip fracture (also slab or fragmented fractures – less common)

Involves only one joint surface© Clark Equine Clinic

Lameness in the Knee

Anatomy of the knee: Two stacked rows of cuboidal bones (6) Three joint spaces All held together by intercarpal

ligaments Radius above, cannon below

compressive force! Faulty conformation (back at the

knee) predisposed Decreased incidence in European

racehorses as opposed to American why?

The Knee Joint

Front Limb - Fetlock Bones of the Fetlock Joint: Cannon,

Proximal Sesamoid Bones (2), Long Pastern Bone

Fractures Fairly common! Usually on the medial side of the long pastern

bone, less often on end of cannon Former seen in race horses on hard surfaces, latter

when training begins Lameness most obvious at trot

Gets worse with workUsually can’t produce pain with palpation, but can feel heatUse opposite limb as comparison

Lameness – Fetlock

Fracture of sesamoid bones: Common in racing Thoroughbreds,

Standardbreds and Quarter Horses Forelimbs most commonly

affected in TB and QH, hindlimbs in STB

Lameness is very pronounced – often non-weightbearingSwelling, heat, painFetlock held rigid during movement

Front Limb – Pastern Joints

TWO joints (Long pastern-short pastern and short pastern-coffin bone)

Ringbone New bone growth on bones of pastern

joint(s) leading to arthritis and fusion of joints

High = top joint Low = bottom joint

Pastern Joint - Ringbone

Articular vs. Non-articular Non-articular due to inflammation of

the periosteum Most common in

non-speed horses with coarse boxy pasterns

Horses with high heels and short toes with trappy gaits

Pastern Joint – Ringbone

Articular High ringbone Horse used for high speed that make quick

stops, short turns or rapid twisting movements Overly upright

pasterns increased concussion on joint

Signs of lameness arenot specific

Fusion of pastern jointcommon

Ringbone

Front Limb – Navicular Bone

“Navicular Syndrome” aka Podotrochleosis Most common cause of intermittent, shifting

forelimb lameness Most common in horses

4-15 years old Most common lameness

of horses between 4 and 9 yo Hereditary (small feet,

faulty conformation) Highest incidences in Quarter Horses

and Standardbreds Geldings > Stallions > Mares Lameness exhibits as heel pain

Navicular Syndrome Predisposing factors:

Poor conformation Upright pasterns

Inappropriate exercise Resilient surfaces

Improper/irregular trimming Long toe-low heel (broken-back axis)

@ walk and trot Lands toe first excessive wear of the toe,

bruising Lower limb flexion test aggravates 80% of

horses Stiff shuffling gait with high head and rigid

neck When circled, limb on inside will be worse,

head held to outside of circle

Hind Limb – Stifle

Bones involved: femur, tibia, patella (knee cap)

Most commonly mis-diagnosed lameness area (overdiagnosed)

Hard to discern differences due to stifle vs. hock

Common Problems: DOD … Upward Fixation of the Patella Arthritis and inflammation (gonitis)

Upward Fixation of the Patella

Locked Stifles Middle and medial patellar

ligaments get “caught” on the femur Patella should be able to slide during

movement, if ligaments stuck, patella can’t move

May be intermittent or complete Acute = hindlimb locked in extension

Stifle and hock can’t flex (but fetlock can) Catching (not complete locking) also

possible

Upward Fixation of the Patella

Diagnosis: Catching most noticeable when horse is

turned in a tight circle towards affected limb Walk up and down slope – crouched position

going up, jerky gait down Toe drag if limb locked Palpation – patella locked in extension

Treatment: Training to improve muscle tone Avoid exercise in soft areas Surgery as last resort

Locked Stifles

NORMAL

LOCKED

Stifle – Arthritis and Gonitis

Gonitis = inflammation Many causes Distension of the stifle joint Gluteal muscles may be atrophied Wearing of toes in the hind end (toe

drag) More lame when ligaments or cartilage

involved Shortened stride (failure to reach

forward) Hip hike

Arthritis = bony changes

Hind Limb – Hock Bone spavin Bog spavin Fractures Curb Stringhalt Shivers Capped Hock Soft Tissue DOD (Nutrition Course)

When the stifle flexes the hock also flexes and

vice versa!

The Hock Joint

6 cuboidal bones, tibia, cannon, 4 joints

Hock works as a hinge Most movement occurs between the

tibia and the tibial tarsal bone Hock is the pivotal hind limb joint –

all equine exercise disciplines rely on it for performance

The hock absorbs most concussive forces

Most common site of stress related injuries!

Hock Lameness

First noticeable sign is stiffness/soreness in lumbar region of back

Poorly trained chiropractors may “adjust” a horse that really has a primary hock problem!

Pain around inside splint bone Swelling and pain in the joint itself

Specific Conditions

Bone Spavin: General term for degenerative joint

disease or osteoarthritis in the hock joint

Often in both hocks History = back stiffness/soreness with

lameness that may go away with exercise

Excessive wear on the outside of the shoe/hoof

Bony enlargement just below and behind the chestnut

Flexion test!

Specific Conditions Bog Spavin:

General term for distension of joint capsule

Present on inside front of the hock!

Usually representative of an underlying hock problem!

Curbed Hock Sprain of the ligament

that runs down the back of the hock

Common in horses with sickle-hocked conformation

Specific Conditions Capped Hock

Hematoma at the point of the hock

Often due to trauma (kicking walls, etc.)

Avoid drainage due to potential for infection

Stringhalt Excessive involuntary

flexion of the hock joint Usually isolated Causes unknown

Specific Conditions Stringhalt Study in Australia:

Appears in Late Summer peaking in February

Associated with droughty summers All breeds affected but TBs more, ponies less Recover when removed from paddocks

containing catsear or dandelion

Specific Conditions

Shivers Involuntary muscle movements of limbs

and tail May be caused by EPSM – most other

causes unknown Usually most visible when trying to

back a horse Jerks foot and holds it above the ground

in flexed position

Treatment Terminology

Rest with Controlled Exercise: Out of work (time off!); moderate

controlled exercise such as daily hand-walking

Physiotherapy: Hydrotherapy

COLD – up to 48 hours post-injury to reduce inflammation

HOT – 48 hours after injury to reduce tension, relieve pain

Treatment Terminology

Joint Lavage: Washing dead tissue out of joint with

large amounts of sterile fluid DMSO (dimethyl sulfoxide):

Topical application can reduce joint inflammation

Wear gloves! Corticosteroids:

Anti-inflammatory – helps reduce harmful enzymes in synovial fluid

Usually directly injected into joint

Treatment Terminology

NSAIDs: Non-steroidal anti-inflammatory pain

relief for soft tissue injuries (Bute, Banamine, Aspirin)

Hyaluronic Acid (HA): Natural part of synovial fluid used to

treat synovitis injected directly into joint (after steroids)

Horses often show immediate, long-lasting relief

Joint Fusion: Surgical repair of arthritis

Treatment Terminology

Counterirritation: Blistering, firing, ultrasound to speed

healing