Companion animal mgmt: Musculoskeletal diseases and young musculoskeletal diseases

what percent of the Musculoskeletal diseases involve the appendicular skeleton

70%

With normal functioning joints what do they do

They are shock absorbers

Motion/ flexibility

Articular cartilage protects end of the bone

What are 4 functions of the synovial fluid functions

Lubricates articular surface

prevents bone to bone contact

Supplies nutrients to chondrocytes

Removes any waste products

Types of cartilage two main groups

Superficial/ articular

Deep

What is included in the Superficual/ articular cartilage

Chondrocytes

Collagen

Small number of proteoglycans

What is included in the deep cartilage

Less collagen compared to superficial 

More proteoglycans

what are the 3 Components of cartilage?

Chondrocytes

Proteoglycans

collagen

Age related changes

GAG content/size decreases (GAG is important for joint fluid)

Synovial fluid decreases

Collagen content decreases

When Chondrocytes become damaged  what happens 

GAG/collagen breakdown

Increase in matrix metalloproteinases (MMPs)

Increased production of prostaglandins, leukotrienes,

and thromboxanes

Results in further inflammation

Osteoarthristis OA what age group is affected… general?

Osteoarthritic is classified as ?

Characterized by these factors

Middle aged to seniors are affected

Chronic and progressive

Destructions of articular bone cartilage

thickening of subchondral bone

Formation of osteophytes

Clinical signs of OA

Lameness

Joint heat/ swelling

pain

stiffness

decreased range of motion

Muscle atrophy

OA treatment (think of it like treating a rusty car)

Reduce pain inflammation

Prevent/ slow further degeneration

Support and restore function

What is important regarding fatty acid supplements in OA

Omega 3 preferred over omega-6

Form less inflammatory products

Glycosaminoglycans importance

GAGs form cross linkages

Have anti-inflammatory effects

Provide chondrocytes with chondroitin sulfate and HA precursers

Several forms are available

Glucosamine

Amino acid sugars produced from glucose/ glutamine

Primary component of GAGs/ proteoglycans

Protect/regenerate CT/ cartilage

Stimulates production of collagen/ proteoglycans

NSAIDS what are the benefits

Decreases production of pro-inflammatory products

Inhibition of COX reduces

• Leukotriens

• Prostaglandins

• Thromboxanes

What is a good diet for dogs and cats that are having some joint issues

A diet high in omega-3 faty acids

Added glucosamine/ chondroitin

What is important for a dog that is suffering with OA

Weight loss may eliminate need for expensive surgical procedures

NSAIDs and joint supplements necessary during weight loss phase

Perspective on exercise with OA

Now pro low impact exercise

Start with short periods of time

Start stiff then warms up

Hip dysplasia what happens

Malformation and degeneration of the coxofemoral joint

What are some of the clinical signs of HD

Can be asymptomatic at the start

May eventually observe an abnormal gait

As OA developes there is a decrease in activity, trouble rising, lameness

How to diagnoses HD

Pain elicted during palpatation/ extension of hips

Loss of muscle mass

Ortolani sign (clunk)

HD what does it look like of radiographs

Flattened femoral head

Thickened femoral neck

Shallow/ sclerotic acetabulum

Numerous osteophytes

Orthopedic foundation for animals

OFA normal classification

Excellent- deep seated ball that fits tightly into a well formed socket

Good- well formed congruent hip joint visualized. The ball fits well into the socket and has a good coverage present

Fair- hip joint is wider. the ball slips slightly out of socket. Socket can appear shallow

OFA mild dysplasia 

Significant subluxation present

Ball partially is out of socket

increased joint space

Socket is shallow and only partailly covers the ball

OFA moderate dysplasia

Ball is barely seated in the shaloow socket

Secondaary arthritic bone changes

OFA severe dysplasia

Marked evidence

Ball partly/ completly out of shallow socket

significant arthritc bone changes

What are some signs of arthritic changes 

Acetabulum is almost not visible 

Bone spurs above hip joints

Thickening and remodeling of the femoral head

How to tread HD

Femoral head osteotomy FHO

Total hip replacement

Cranial cruciate ligament rupture

One of the most common orthopedic problems

Usually caused by something

can be a partial or complete rupture

Very common to tear in the opposite leg

CCL rupture what are the clinic signs 

Decreased activity level difficulty rising

trouble jumping

Decreased range of motion

swelling

lameness

muscle atrophy

How to diagnose CCL ruptures

Palpation

Cranial drawer sign

Radiographs

How to treat CCL medically

strict cage rest for 6-8 weeks

NSAIDs

joint supp.

Not considered the gold standard

results in secondary arthritis

CCL treatment Surgical repair

Is considered the gold standard

Intracapsular

extracapsular

TPLO

Osteosarcoma

Most common type of primary bone tumor

Can result in secondary mastasis

Common in large/ giant breeds

75% occur in appendicular skeleton

OSA diagnosis

Radiographs of bone

Radiographs of the chest

Bone biopsy

OSA treatment

Pain control

Radiation

Surgery

OSA prognosis

Median survival w/ palliative care ± amputation or radiation is about 4 months

Median survival with surgery and chemotherapy is about 10 months

Prognosis is better in cats

Median luxating patella

Most common in toy breed dogs

Skip and step, running on three legs, holding up hind leg clinical sign

Miraculously walking on all fours as if nothing has happened

50%have in both hind limps

Grading MLP what is grade 1

Kneecap can be moved out of place manually but will immediately fall back

into its natural position; doesn’t require surgery

Grading MLP what is grade 2

Kneecap occasionally slips out of groove, spontaneously creating an

intermittent lameness. Kneecap will go back in place on its own. May or may not need

surgery

Grading MLP what is grade 3

The patella is out of place all of the time but can be manipulated back into its

normal position manually (but doesn’t stay there). Requires surgery

Grading MLP what is grade 4

The patella is out of place all of the time and no amount of manipulation can

return it to its proper place. Requires surgery

MLP surgical procedure

Lateral imbrication

Trochlear modification

Tibial crest (tuberosity) transportation

young musculoskeletal diseases: Hypertrophic osteodystrophy HOD

Developmental suto inflammatory disease

Unknown cause

Fast growing puppies of large giant breeds

Blood flow decreases to part of bone adjacent to joint

Interruption of bone formation

Bones dont harden correctly

Affects more than one leg at a time

Can permanently damage growth plates

Can be really painful

Self-limiting

Chance of reoccurrence

HOD clinical signs

Slight limp

 Swollen, warm, painful leg bones

 May be non-weight bearing

 Reluctance to get up/walk

 Anorexia

 Weight loss

 Fever

 Depression

How to diagnose HOD

PE and radiographs

HOD treatment

NSAIDS

IVF

Nutritional support

Antibiotics

Restricted exercise

Panosteitis 

Cause is unknown

Involve long leg bones of large breeds

Episodes reoccur

Lameness shifts from one leg to another

Normally outgrow

NSAIDs

Legg calve perthes disease

Aseptic/ avascular necrosis of femoral head

Lameness of the hip joint

Most common in young, small breed dogs

Genetic component

Pathogenesis of Legg calve perthes disease

Interruption of blood supply to head of femur

Portions of bone begin to die

Overlying cartilage that lines hip joint collapses

Results in a painful, poorly fitting hip joint

Clincal signs of Legg calve perthes disease

Crying out when stretching limb/trying to bear weight

 Favoring/lameness of affected leg

 Muscle atrophy

Diagnosis/ treatment of Legg calve perthes disease

Radiographs required

Surgical intervention recommended

Femoral head and neck ostectomy

NSAIDs