Comprehensive Guide to Musculoskeletal Diseases in Veterinary Medicine

Arthrodesis?

Surgical fusion of a joint.

Arthroplasty?

Surgical repair or replacement of a joint.

Cancellous?

Spongy bone tissue.

Cholinergic?

Relating to nerve cells in which acetylcholine acts as a neurotransmitter.

Congenital?

Present from birth.

Crepitus?

A crackling or popping sound in the joints.

Cruciate ligaments?

Aka ACL; ligaments in the knee that cross each other.

Diaphysis?

The shaft of a long bone, made up of compact bone.

Endochondral?

Bone development from cartilage.

Epiphysis?

The ends of long bone, made up of cancellous bone.

Luxation?

Dislocation of a joint.

Mypoathy?

Disease of muscle tissue.

Myositis?

Inflammation of muscle tissue.

Neuromuscular junction?

The synapse between a motor neuron and a muscle fiber where muscle fiber contraction occurs.

Osteotomy?

Surgical cutting of a bone.

Panosteitis?

Aka growing pains; self-limiting, painful inflammation of the outer surface or shaft of long bones of the legs.

Sarcomere?

Contractile unit muscle tissue.

Ossification?

The process where matrix hardens into bone; also calcium & phosphorus will enter during this period

Intramembranous ossification?

Bone formation that occurs in the connective tissue membrane, converting connective tissue to both cancellous & compact bone in multiple sites, & produces flat bones.

What is bone constantly doing?

Being broke down, remodeled, & produced.

Which type of bone is active in the production of RBCs?

Epiphyseal.

What doe calcitonin & parathyroid hormone do in regards to the musculoskeletal system?

Balance the level of calcium in bone & blood by constantly adjusting levels to meet the body's needs.

What hormones balance the level of calcium in bone & blood?

Calcitonin & phosphorus.

Skeletal muscle?

Striated and voluntary muscle tissue.

Neuronal stimulation?

Process by which neurons activate muscle fibers.

Analgesics?

Medications used to relieve pain.

What is the musculoskeletal system responsible for?

Movement & shape.

In general, what is the musculoskeletal system composed of?

A rigid frame (aka bone), flexible articulations (aka joints), & a system of pulleys (aka cartilage, tendons, ligaments, & muscles).

What can cause issues with the musculoskeletal system?

Trauma, degenerative diseases, inflammation (such as myositis & panosteitis), poor conformation, & neoplasia.

What are disorders of the musculoskeletal system often associated with & what is affected?

Associated with pain & limited mobility, affecting bones, joints, and/or muscles.

What is the hardest substance in the body?

Enamel.

What is the 2nd hardest substance in the body?

Bone.

What is the hardest living tissue in the body?

Bone.

What is the function of the musculoskeletal system?

Capable of repair after injury, protect internal organs, & the main storage area for calcium & other minerals.

In regards to storage of minerals, what happens when bone is damaged?

Storage capacity & ability are decreased.

What is an important medical purpose of long bones?

They are the prime area for collection of bone marrow samples.

How does long bone growth begin as in fetal stages of development?

Cartilage.

What process does long bone harden through & when does it begin?

Endochondral ossification as the body develops after birth.

What replaces cartilage during bone growth?

Osteoblasts, osteoclasts, & osteocytes.

What does osteoblasts, osteoclasts, & osteocytes replace during bone growth?

Cartilage.

Osteoblasts?

Cells that form new bones & grow & heal existing bone.

Osteoclasts?

Dissolve & break down old or damaged bone cells.

Osteocytes?

Aka bone cells; form when osteoblasts become embedded in matrix.

How does muscle fiber contraction happen?

Through neuronal stimulation & with increased calcium released in the muscle fibers.

How does muscles move bone?

When multiple muscle fibers contract simultaneously.

What is formed by muscle & bones working together?

Joints, allowing mechanical movement of the limbs.

What gives support to joint movement?

Tendons & ligaments.

Open fractures?

Aka compound; where the bone penetrates through the skin and is visible externally.

Closed fractures?

Contained within the skin.

Complete fracture?

When the bone breaks into two or more pieces.

Incomplete fracture?

Has not broken all the way through.

Simple fracture?

Has broken in a clean line.

Comminuted fracture?

Complete fracture where the bone has splintered or fragmented at the break, involving multiple small bone fragments.

Linear fracture?

Aka fissured fracture; incomplete fracture where the fracture line runs parallel to the axis of the bone.

Greenstick fracture?

Incomplete fracture where the bone is not separated but is bent.

Transverse fracture?

Complete fracture where the fracture line is at a right angle to the bone's axis.

Oblique fracture?

Complete fracture where the angle of the fracture line is at an angle to the axis of the bone.

Bone fracture diagnosis?

Crepitus upon palpation.

Radiographs: useful for fracture visualization & classification.

Also presenting clinical signs, history, history of trauma.

Clinical signs of bone fractures?

Very painful, which can present as whining or other vocalizations, aggression, & inability to get comfortable.

Lameness, possibly non-weight bearing, inflammation, loss of function, crepitus, or change in limb formation.

Open fractures will have bone sticking out the skin.

Bone fracture treatment?

External coaptation, internal coaptation, or external fixators.

Bone grafts, antibiotics (especially open fractures and/or surgical repair), and/or analgesics.

And possibly physical therapy & rehab to help regain proper function & muscle strength.

Diagnosis of bone fractures

Presenting signs and history, history of trauma, crepitus upon palpation, and radiographs for visualization and classification.

Treatment of bone fractures

Reduction and fixation of the fracture, external coaptation (splints or casts), internal coaptation (surgical repair with bone pins, plates, wires, and screws), and possibly external fixators.

When does reduction & fixation of the fracture need to be done?

As soon as the patient is stable.

External coaption?

Fixators attached from outside of the skin, including casts & splints.

Internal coaptation?

Fixators attached inside the skin directly onto the bone & tissues, includes pins, plates, wires, & screws.

Are antibiotics useful for bone fractures?

Yes, especially in the case of open fractures or surgical repair.

Are analgesics necessary for bone fractures?

Yes.

What is the purpose of physical therapy with bone fractures?

May be needed to help the animal regain proper function and muscle strength.

Client education for bone fractures?

Activity must be restricted while healing, which can take weeks to months; leash walking and cage rest may be necessary.

What should owners watch for after bone fracture repair?

Drainage, swelling, heat in the affected limb, changes of limb usage, & if the animal is chewing or messing with the cast, splint, or bandages.

What is a risk of using plates or pins as fixators for bone fractures?

They are stronger than the bone, so they could potentially refracture the bone.

Cruciate ligament injury?

One of the most common reasons for hind limb lameness, involving a tear or rupture of the ligament, commonly at the middle of the ligament.

What is one of the most common reasons for hind limb lameness?

Cruciate ligament injury.

Partial tear of cruciate ligament?

Can heal on its own with enough time and quality rest, though it may not be perfect.

Clinical signs of cruciate ligament injury?

Lameness, non-weight bearing, pain, joint effusion, crepitus, abnormal gait, decreased activity, muscle atrophy, decreased range of motion, drawer sign, & sitting abnormally with legs out to the side.

Drawer sign?

Excessive cranial laxity of the tibia in relation to the femur (aka increased tibial rotation); true full test for cruciate ligament injury & must be done under sedation.

What can cause a cruciate ligament injury?

Commonly due to trauma; also weakened ligament secondary to autoimmune disease, degeneration, or conformational deformities.

What can cruciate ligament injuries lead to?

Secondary osteoarthritis, injuries of the meniscus, & joint effusion.

Diagnosis of cruciate ligament injury?

Orthopedic exam presenting clinical signs and history, drawer sign, arthrocentesis revealing inflammation and blood in the joint, and radiographs showing osteoarthritis and joint changes.

Cruciate ligament injury treatment?

Includes medical treatment and surgical repair.

Medical treatment for cruciate ligament injury?

Weight loss and management, physical therapy, cage rest, anti-inflammatory drugs, analgesics, and possible joint supplements.

Surgical repair techniques for cruciate ligament injury?

Osteotomy techniques such as Tibial plateau leveling osteotomy (TPLO), which is commonly the preferred treatment, and tibial tuberosity advancement (TTA).

TPLO technique?

Changes the orientation of the tibia, resulting in a 90° attachment of the quadriceps.

TTA technique?

Advances the tibial tuberosity forward after a cut to the anterior aspect of the tibia, resulting in a 90° attachment of the quadriceps.

Stabilization in cruciate ligament injury?

Results by changing the way the stifle works due to the orientation of the tibia and the quadriceps.

Advantages of surgical techniques for cruciate ligament injury?

Result in less progressive joint damage and a more stable joint as compared to the suture techniques.

Suturing techniques for cruciate ligament injury?

Includes extracapsular suture stabilization and a tightrope technique.

Tightrope technique?

A newer technique involving suture and toggles with holes drilled in the bones.

Extracapsular suture stabilization?

Less expensive and less traumatic but has a common failure in large breed and active dogs.

Client education for cruciate ligament injury?

Limited activity and cage rest during surgical recovery is imperative; after the animal has had time to heal, light exercise will be needed to rebuild the muscles.

Patellar luxation?

Movement of the patella from the femoral (trochlear) groove, medially or laterally also unilateral or bilateral.

What is patellar luxation often associated with?

Other joint or bone disorders or limb deformities.

What can patellar luxation lead to?

Osteoarthritis & long term joint damage.

Common breeds are more predisposed to patellar luxation?

Toy and small breeds (e.g., poodles, chihuahuas, jack russells).

What is the most common stifle disorder in dogs?

Patellar luxation.

What are some general causes of patellar luxation?

Genetic predisposition & trauma.

When does hereditary patellar luxation disorder show clinical signs?

Within the first few months of life.

Skipping lameness?

Common sign of patellar luxation; the affected limb will be held out behind them & they may possibly shake it, & they may not bear weight on the limb while the patella is out of place.

Clinical signs of patellar luxation?

Abnormal gait or conformation (bowlegged or knock kneed) & pain only when the patella is out of place.

Diagnosis of patellar luxation?

The stifle will feel unstable upon palpation; radiographs determine the degree of the disorder.