Musculoskeletal Disorders in Small Animals: Diagnosis, Treatment, and Pathophysiology

What are common musculoskeletal disorders in small animals?

Arthritis, luxating patella, hip dysplasia, traumatic injuries (fractures, cruciate rupture), and osteosarcoma.

What is the primary focus of orthopedics in small animals?

To address musculoskeletal problems that affect how the animal moves.

what is the function of the skeletal system in dogs and cats?

provides support, protection for organs, and enables movement through a framework of bones

When are the bones placed under more pressure?

jumping up and down from high places, excessive running, other high impact activities

What factors can contribute to skeletal development in dogs?

Genetic, environmental, and nutritional factors.

genetic component in the skeletal system?

can be influenced when the populations are well controlled,

accurate breeding records are kept, and a desire to improve the

breed exists

Nutrition in the skeletal system?

Energy, protein, and calcium

Maximizing the growth rate in young, growing puppies does

not correlate to maximal adult size but increase what?

the risk of skeletal disease

What is cartilage made up of?

matrix , chondrocytes (secrete the cartilage matrix), and hyaluronan (binds and connects the proteoglycans together in the matrix)

Hyaline(articular) cartilage

covers the end of bones, provides a smooth,

frictionless surface, shock absorber

joint capsule

Joints encased in a fibrous

structure

what fluid does the joint capsule produce?

synovial fluid

diagnosing musculoskeletal disorders

Radiographs, advanced imaging, arthroscopy, locating the problem area, thorough physical and orthopedic examination +/- sedation

what is the goal diagnosing musculoskeletal disorders?

to localize the cause(s) of lameness, Observe mm mass, standing,recumbent, gait analysis

What are the treatments for inciting the cause of feline arthritis?

surgery, lifestyle, pharmacologic, Nonpharmacologic, stem cell therapy

What is the most common form of joint disease in dogs?

Osteoarthritis (OA).

What is the difference between DJD and osteoarthritis?

DJD is a general term for any degenerative change in joints, while osteoarthritis specifically refers to pathological changes in synovial joints with cartilage deterioration.

What are the clinical signs of arthritis in animals?

Stiffness after rest, joint pain, reluctance to jump or exercise, lameness, and in cats, decreased grooming and hiding.

What are common causes of arthritis?

Trauma, infection, immune-mediated diseases, developmental malformations, and abnormal stresses on cartilage.

What is the pathophysiology of arthritis?

Chondrocyte necrosis, release of degradative enzymes, synovitis, cartilage destruction, and joint dysfunction leading to pain and lameness.

the characteristic of pathophysiology?

hyaline cartilage thinning, joint effusion, periarticular osteophyte formation, PAIN!!

Is it easy to elicit pain during a clinical examination of cats with feline arthritis?

No, it can be very difficult.

What can behavioral changes in cats with feline arthritis be easily mistaken for?

Advancing age.

diagnosis of feline arthritis?

signalment(breed), history, Physical exam, diagnostic test (rads)

What is articular cartilage and its function?

A smooth surface that allows bones to glide over each other, providing a frictionless surface and acting as a shock absorber.

What is the role of chondrocytes in cartilage?

They secrete the cartilage matrix.

What is the significance of proteoglycans in cartilage?

They surround collagen fibers and help cartilage absorb water, contributing to its resilience.

What are the effects of obesity on the musculoskeletal system?

Excess weight places more stress on bones and joints, contributing to diseases.

What diagnostic steps are important for musculoskeletal disorders?

Thorough history, physical examination, and possibly radiographs or advanced imaging.

What are the signs of feline arthritis compared to canine arthritis?

Feline arthritis may be more prevalent but harder to detect; cats may show behavioral changes rather than overt signs of pain.

What is the function of synovial fluid in joints?

It lubricates the joint and reduces friction during movement.

What are the common types of cartilage found in joints?

Hyaline (articular) cartilage, which covers the ends of bones.

What is the impact of high-impact activities on the skeletal system?

They can contribute to bone and joint diseases in dogs.

What is the importance of nutrition in skeletal health?

Proper nutrition, including energy, protein, and calcium, is crucial for skeletal integrity, especially in growing puppies.

What are the key components of cartilage matrix?

Collagen, proteoglycans, and chondrocytes.

What role does hyaluronan play in cartilage?

It binds and connects proteoglycans in the cartilage matrix.

What are the phases of growth critical for skeletal integrity?

The growth phase of 3 to 8 months and the phase prior to weaning.

What are common diagnostic tests for joint pain?

Radiographs (X-rays)

What is the primary goal of treatment for joint issues?

To address the inciting cause if possible.

What surgical procedure may be needed for joint stabilization?

Surgery

What lifestyle changes can help manage joint issues in pets?

Diet adjustments and providing ramps or stairs.

What are Disease-Modifying Osteoarthritis Drugs (DMOADs)?

Drugs like PSGAGS used to treat osteoarthritis.

What are the potential side effects of NSAIDs in pets?

Gastrointestinal, renal, and hepatic dysfunction.

What nonpharmacologic treatments can be used for joint pain?

Rehabilitation, nutraceuticals (like chondroitin sulfate), acupuncture, and laser therapy.

What is Osteochondritis Dissecans (OCD)?

A developmental disorder in medium and large rapidly growing dogs.

What are the key characteristics of OCD?

Abnormal endochondral ossification, cartilage thickening, and potential cartilage detachment.

What are common clinical signs of OCD in dogs?

Intermittent lameness and pain, especially after activity.

What diagnostic methods are used for OCD?

Radiographs and arthroscopy.

What are the treatment options for OCD?

Conservative cage rest 6-8 weeks, surgical repair-arthroscopy, anti-inflammatory drugs, diet control and exercise restriction.

what complications are caused by OCD?

incites the development of osteoarthritis or

degenerative joint disease of the shoulder

what do cast or splints do to small animals with fractures?

weight of a cast or splint may make it

difficult for the animal to move around

What is a fracture?

A break or crack in a bone.

What is the difference between a closed fracture and an open fracture?

A closed fracture does not break the skin, while an open fracture does.

What is a dislocation?

An injury where a bone is displaced from its joint.

What is a sprain?

An injury to a joint, ligament, or tendon without dislocation or fracture.

What are the types of fractures?

Closed, open, simple, compound, epiphyseal, and greenstick.

Fractures involving growth plates

They are softer than other bone regions and most growth occurs during 4-8 months of age.

What is the Salter-Harris classification?

A system used to classify fractures involving growth plates.

What are common causes of fractures in pets?

Traumatic events like jumping or falling, and pathologic fractures from preexisting diseases.

What is the treatment protocol for fractures?

Images, infection treatment, shock, fracture reduction, and pain management, rehab.

What are common fractures in puppies?

Humeral condylar fractures due to impact injuries for puppies between 4-6 months.

What breeds are commonly affected by distal radius and ulna fractures?

Small or toy breeds like Pomeranians and Chihuahuas that affect the bottom of the front limb.

What is luxating patella?

A condition where the patella moves outside the femoral groove when the knee is flexed.

What is the primary consequence of the knee cap riding out of its groove?

Damage to cartilage, leading to osteoarthritis and associated pain.

Which small dog breeds are commonly affected by luxating patella?

Yorkies, Poodles, Boston terriers, and many other small breeds.

Name some large breeds that can also be affected by luxating patella.

Labrador retrievers, Golden retrievers, and Akitas.

What are the traumatic causes of luxating patella?

Injury or secondary to cranial cruciate ligament (CCL) rupture.

List some non-traumatic causes of luxating patella.

Shallow femoral groove, weak ligaments, malformation of femur or tibia, malalignment of tendons and muscles.

What characterizes Grade I patellar luxation?

Patella can be luxated with pressure but returns to place when pressure is released.

Describe Grade II patellar luxation.

Patella intermittently pops out on its own and remains out until the leg is manipulated.

What happens in Grade III patellar luxation?

Patella is out of the groove most of the time but can be manually pushed back.

What defines Grade IV patellar luxation?

Patella is permanently out of the groove and cannot be manually repositioned.

What is a common diagnostic method for luxating patella?

Manipulating the stifle joint and pushing the patella in and out of position.

What are the history signs of luxating patella?

Skipping gait, reluctance to jump, intermittent or constant lameness, and stiffness due to arthritis.

What is the prognosis for surgical correction of luxating patella?

Generally very good; about 90% of dogs have a very good outcome.

What is hip dysplasia?

An abnormal coxofemoral joint resulting in joint laxity and degenerative joint disease (DJD).

What factors causes hip dysplasia?

Excessive growth, nutrition (no fat puppies), exercise, and genetic factors.

What occurs to the femur in hip dysplasia as the dog bears weight?

The head of the femur comes out of the acetabulum, stretching the joint capsule and ligament.

hip dysplasia signalment history

the adolescent dog, typically 6-18 months of age and in pain/+ clinical signs(Dogs show signs of hip dysplasia as early as 4 to 11 months of age)

• elderly dogs, after they have been walking on their poorly formed hips for many years(no clinical signs at a young age)

pathophysiology of CHD

-proliferative fibroplasia or thickening of the joint capsule

-formation of osteophytes or new bone on the rim of the acetabulum and the femoral neck

What are common clinical signs of hip dysplasia?

Lameness, bunny hopping when running, difficulty getting up, reluctance to exercise, and severe pain.

What diagnostic tests are used for hip dysplasia?

Palpation (Ortolani test) and imaging (OFA and PennHip).

What is the goal of conservative therapy for hip dysplasia?

To relieve pain and maintain limb function while allowing normal activity levels while controlling weight, moderate excerise, analgesics.

What are some surgical treatments for hip dysplasia?

FHO (femoral head osteotomy), total hip replacement (THR), and triple pelvic osteotomy (TPO).

will majority of dogs having TPO surgery imporve?

they will grealty imporve if not normal

What is the significance of age in candidates for total hip replacement?

Candidates should be mature (at least older than 10 months) to ensure better surgical outcomes.

what are the 3 parts of total hip replacement?

femoral head, stem and acetabulum

What are the indications for a total hip replacement?

Hip dysplasia, arthritis, fractures, and hip luxations.

What is the most commonly diagnosed orthopedic problem in dogs?

Cranial cruciate ligament rupture (CCL).

How do CCL tears in dogs typically occur?

Most tears are due to degenerative changes in the ligaments associated with normal activities.

What is the function of the cranial cruciate ligament?

To prevent forward and backward sliding of the femur on the tibia.

What percentage of dogs will rupture the CCL in the opposite stifle?

One out of three dogs.

What are the three presentations of CCL rupture in dogs?

Acute injury, chronic injury, and partial tears.

What are the symptoms of acute CCL tears in dogs?

Sudden onset of non-weight-bearing or partial-weight-bearing lameness.

What are the symptoms of chronic CCL tears in dogs?

Prolonged weight-bearing lameness,

worsens with time

What are the symptoms of partial CCL tears in dogs?

Mild, intermittent lameness (worsens with activity and improves with rest,makes early diagnosis challenging)

What can happen without treatment for a CCL rupture?

Severe pain, lameness, joint instability, further damage, and osteoarthritis.

What diagnostic tests are used for CCL rupture?

Cranial drawer movement and tibial compression test.

What is the 'Buttress Sign' in CCL rupture diagnosis?

Swelling on the medial tibial plateau indicating periarticular fibrosis.

joint effusion in cruciate rupture diagnosis

Can often be felt next to the patellar tendon