Orthopedic surgery

Question 1

Define meta-, epi-, diaphysis.

Answer 1

epi is at the end (covered with physeal
cartilage)

meta is the “neck” of the joint

dia is mid long bone (usually has a big blood vessel going along it suppling the bone with blood)

Bleeding from bone is classified as parenchymal bleeding.

Externally, the bone is covered with periosteum, absent only at bone ends. The periosteum contains nociceptors.

Question 2

Location of epiphyseal plates.

Note the anatomy.

Answer 2

See image.

Question 3

What is pictured?

Answer 3

The bone cortex is one of the first things you should evaluate on a bone x-ray. Assess the density. The cortical density should be higher than medullar.

The cortex is correctly thicker along the diaphysis and thinner along the epiphysis.

Is an indicator of bone health.

Question 4

Osseous tissue is a connective tissue and like all connective tissues contains

Answer 4

relatively few cells (2% of mass) and large amounts of extracellular matrix.

By mass, osseous tissue matrix consists of 1/3rd collagen fibers and 2/3rds calcium phosphate salt.

The collagen provides a surface for inorganic salt
crystals to adhere.

Question 5

Osteogenic cells are undifferentiated and develop into

Answer 5

osteoblasts.

The osteoblast is the bone cell responsible for forming new bone and is found in the growing portions of bone. Osteoblasts deposit bone matrix.

Osteoclasts develop from a different cell lineage and act to resorb bone.

Question 6

When osteoblasts get trapped within the calcified matrix, they become

Answer 6

osteocytes.

Osteocytes maintain bone tissue.

Osteoclasts develop from a different cell lineage and act to resorb bone.

Question 7

Most common orthopaedic conditions in dogs. (8)

Answer 7

¤ Hip Dysplasia
¤ Elbow Dysplasia

¤ Cranial Cruciate Ligament Rupture
¤ Patellar Luxation

¤ Secondary osteoarthritis
¤ Panosteitis

¤ Legg-Calve-Perthes disease
¤ Bone neoplasia

Question 8

Canine hip dysplasia (CHD) is

Answer 8

a genetic and multifactorial developmental disorder
characterized by hip joint laxity, degeneration, and
osteoarthritis (OA).

Question 9

Answer 9

Question 10

Answer 10

Question 11

Canine elbow dysplasia (CED) is

Answer 11

a disease of the elbows of dogs.

Elbow dysplasia includes any mismatch of growth and development between the radius and ulna.

This in turn can cause damage to the joint cartilage and even fracture the tip of the coronoid process.

First look for a gap in the elbow joint. It should be a nice, round space so the bigger the “step”, the worse the incongruence and thus elbow dysplasia.

Question 12

Answer 12

ununited anconeal process (UAP) a form of elbow dysplasia

Is a developmental abnormality in which the anconeal process does not fuse with the ulna.

The loose piece of ulna should be removed.

Question 13

Panosteitis is

Answer 13

a spontaneously occurring, self-limiting (should resolve in 3ish weeks) disease of young, large breed dogs involving both the diaphyseal and metaphyseal areas of the tubular long bones.

Panosteitis begins with adipocyte degeneration,
intramembranous ossification, and bony remodeling that results in medullary fibrosis and periosteal/endosteal new bone formation.

Tx with NSAIDs for a few weeks.

palpation of the bones is painful but joint flexion is not.

Question 14

Answer 14

left image shows some increased medullary density.

Question 15

Answer 15

panosteitic changes in the medulla (increased density)

Question 16

Legg-Calve-Perthes disease

Answer 16

Legg-Calve-Perthes disease is also known as avascular or aseptic necrosis of the femoral head.

This is a condition in which the head of the femur
spontaneously begins to degenerate.

Question 17

Answer 17

osteosarcoma

Usually seen at:
* distal femur
* proximal tibia
* distal radius
* porximal humerus

Question 18

Answer 18

Question 19

Answer 19

osteosarcoma

Question 20

Most common orthopaedic
conditions in cats. (3)

Answer 20

¤ Primary osteoarthritis (pictured)

¤ Hip dysplasia (Siamese cats, Maine Coon)

¤ Slipped capital femoral epiphysis which is essentially just feline legg-perthes’ (Maine Coon)

Question 21

Answer 21

which is essentially just feline legg-perthes’

Question 22

The orthopedic examination can begin prior to assessment by

Answer 22

considering the patient’s signalment. The astute clinician will consider differential diagnoses based
on:
¤ Age
¤ Breed
¤ Presenting complaint

Question 23

Breed predispositions in:
¤ Elbow dysplasia:
¤ Medial patellar luxation:
¤ Cranial cruciate ligament disease:

Answer 23

Elbow dysplasia:
¤ Labrador retriever
¤ Rottweiler
¤ German shepherd dog
¤ Staffordshire bull terrier

Medial patellar luxation:
¤ Chihuahua

Cranial cruciate ligament disease:
¤ Rottweiler
¤ Labrador retriever

Question 24

An orthopedic examination begins by

Answer 24

observing the animal for signs of lameness. The correct limb may not have been identified by owner.

The animal should be observed for reducing the weight placed on the affected limb when standing or sitting.

Unilateral or bilateral muscle atrophy and abnormal
muscle development, instability, or crepitation (e.g., fracture).

It is preferable to begin examining a healthy limb to
identify the individual’s normal response to manipulation and pressure.

Asymmetry may indicate tumor, abscess, atrophy, joint swelling, or greenstick fracture.

Greenstick fractures are a type of broken bone that happens when a bone bends enough to crack on one side without snapping into multiple pieces.

Question 25

Animals with forelimb lameness will

Answer 25

lift their heads after the lame limb strikes the ground in an attempt to remove weight from the affected limb. A short stride occurs when the animal has a decreased range of motion in a diseased joint. ## Footnote "down on sound"

Question 26

After the lame limb has been identified, the animal should be

Answer 26

palpated, and a screening neurologic examination should be performed. The examiner should develop a consistent evaluation procedure. You can start at the front of the animal and work toward the rear, or do opposite. Starting at the toes of each limb and progressing proximally. Joints should be isolated and moved through a complete range of motion to detect crepitation, pain, or abnormalities in range of motion.

Question 27

Cruciate ligaments test.

Answer 27

Test the integrity of the cruciate ligaments by trying to elicit a cranial or caudal drawer motion or by performing a tibial compression test to elicit cranial tibial thrust. Drawer movement is caused by the tibia sliding cranially or caudally in relationship to the femur. This motion is not possible when the cruciate ligaments are intact in adult animals

Question 28

What is the tibial compression test?

Answer 28

Another test for cranial cruciate ligament rupture in addition to the drawer test. an be performed with the patient standing or in lateral recumbency (affected leg up), awake or sedated. The stifle is held in slight flexion. The index finger of one hand is placed over the tibial crest. The other hand flexes & extends the hock. If the ACL is torn, the tibial tuberosity will move cranially, ever so slightly, as the hock is in the flexed position. The reason for this displacement is that hock flexion causes tension of the gastrocnemius muscle, which in turn displaces the tibia cranially. This is called tibial compression or cranial tibial thrust.

Question 29

What are extracellular vesicles?

Answer 29

Extracellular vesicles (EVs) are cell-derived membrane-surrounded vesicles that carry bioactive molecules and deliver them to recipient cells. Classical EVs are exosomes, microvesicles, and apoptotic bodies. These look different in health vs with cancer. In the future, the aim is that these can be analyzed to test for neoplastic disease such as osteosarcoma.

Question 30

Palpating for hip luxation:

Answer 30

Use the position of the greater trochanter in relationship to the tuber ischium as a landmark. In the standing animal, compare the distance from the greater trochanter with the tuber ischium bilaterally. With hip luxation, the trochanter rolls over the thumb.

Question 31

To detect hip laxity associated with hip dysplasia perform...?

Answer 31

perform the Ortolani maneuver to detect hip laxity associated with hip dysplasia With the animal in lateral recumbency, Place one hand over the dorsal pelvis. Grasp the stifle with the other hand, and orient the femur parallel with the table surface. Simultaneously adduct and push the stifle toward the pelvis. Maintain the pressure and abduct the stifle. As the femoral head returns to the acetabulum, use the hand stabilizing the pelvis to detect a click.

Question 32

pathologic or spontaneous fractures may be caused by internal pathologies such as: (4)

Answer 32

¤ neoplasia (osteoma, osteosarcoma) ¤ metabolic disorder ¤ hormonal diseases ¤ age–related changes

Question 33

Bone fractures are classified according to several criteria: (5)

Answer 33

¤ etiology, ¤ presence of external injuries, ¤ localisation/course of fracture line, ¤ bone damage, ¤ fracture stability Closed fractures – are those, where the ends of the fractured bone do not contact external environment. Open fractures – are those, where the skin and surrounding soft tissues are penetrated or damaged, and bone fragments contact external environment. These fractures are commonly infected and their recovery may be complicated.

Question 34

Bone fracture Classification according to localization:

Answer 34

Tubular bone fractures may be classified as: ¤ Metaphyseal fractures ¤ Epiphyseal fractures ¤ Diaphyseal fractures

Question 35

Bone fracture Classification according of fracture line. (8)

Answer 35

¤ Transverse fracture – fracture line is perpendicular in relation to the longitudinal axis of the bone. ¤ Oblique fracture – there is an acute angle between the fracture line and longitudinal axis of the bone. ¤ Longitudinal fracture – fracture line goes along the longitudinal axis of the bone. ¤ Spiral fracture – fracture line goes spirally along diaphysis of the tubular bone. Simple fracture – the bone is fractured in only one place and is split into two parts. Either: ¤ Incomplete simple: Fracture through only one cortex ¤ Complete simple: Fracture through both cortices ¤ Comminuted fracture – the type of fracture that results in numerous small splinters. ¤ Articular fracture – fracture line penetrates articular cavity; this type of fracture is often termed – intraarticular fracture. ¤ Avulsion fractures occur when the insertion point of a tendon or ligament is fractured and distracted from the rest of the bone.

Question 36

Name the fracture types.

Answer 36

Question 37

A greenstick fracture is

Answer 37

occurring in immature animals, is an incomplete fracture in which a portion of the cortex is intact, thus stabilizing the bone to some extent.

Question 38

Answer 38

Avulsion fractures occur when the insertion point of a tendon or ligament is fractured and distracted from the rest of the bone.

Question 39

Describe Bone fracture healing.

Answer 39

Osseous tissue heals after the fracture via bone callus formation. Periosteum, endosteum (the layer covering the cortex from inside), bone marrow, and blood vessel endothelium participate in the regeneration process. Four phases may be distinguished in the process of callus formation. * Phase 1, inflammation * Phase 2, soft callus granulation * Phase 3, hard callus (ossification) * Phase 4, remodeling

Question 40

Four phases may be distinguished in the process of callus formation:

Answer 40

* Phase 1, inflammation * Phase 2, soft callus granulation * Phase 3, hard callus (ossification) * Phase 4, remodeling

Question 41

Describe bone fracture healing. Phase 1 – Inflammation: (4)

Answer 41

Occurs over the first 48–72 hours after the fracture, a serous aseptic inflammation, exudation, and migration of leukocytes and inflammatory mediators occur in the fracture area. Haematoma! Demineralisation and resorption occurs at bone ends due osteoclasts and their ferment – acidic phosphatase. Fibrin is the first supportive tissue that holds bone fragments together.

Question 42

Describe bone fracture healing. Phase 2 – soft callus formation (granulation): (4)

Answer 42

Occurs over the 3–4 days after the trauma, connective or fibrous matrix starts to form. At first, osteoid tissue is formed in periosteum, endosteum, and bone marrow and, then, develops further to the fracture line. New blood vessels start growing into the clot from the vessels coming from the medullary cavity, periosteum, and other surrounding soft tissues. Granulation tissue develops above the clot and forms connective tissue callus.

Question 43

Describe bone fracture healing. Phase 3 – hard callus formation (ossification):

Answer 43

Ossification starts on day 10–12. Callus size is directly related to the stability of the fracture. If the fracture is not stable, callus may be relatively large to redistribute and decrease pressure in the area. If fragment fixation is good, irregularly located osseous tissue elements appear in the primarily cartilaginous callus.

Question 44

Describe bone fracture healing. Phase 4 – bone remodelling:

Answer 44

¤ The newly formed osseous tissue has not yet acquired its final structure and its function is incomplete. ¤ When the limb starts performing support and motion functions, the callus is staticodynamically restructured according to functional needs. ¤ Eventually, the fracture site becomes architecturally similar to the normal bone. ¤ This is a relatively long process that may take years, depending on the age and general state of the animal.

Question 45

Stabilization of the bone fracture patient.

Answer 45

Administer proper analgesia as soon as possible. Ideal analgesics are pure mu opioids, such as: * Methadone: Dogs, 0.2 to 0.3 mg/kg; cats, 0.1 up to 0.3 mg/kg; IV or IM q6-8H * Fentanyl: Dogs/cats, 2 mcg/kg loading dose followed by 2 to 10 mcg/kg/h CRI (caution with cats). Check and stabilize vitals (temperature, pulse quality and heart rate, respiration rate, blood pressure, pulse oximetry), if needed. Perform thorough physical, orthopedic, and neurologic examinations. Pursue diagnostics such as blood analysis, thoracic and abdominal radiographs, and an AFAST ultrasound (if needed). Resolve any life-threatening issues, which means that surgery may need to be delayed for several days due to conditions, such as pulmonary contusions or hypovolemia.

Question 46

Bone fracture clinical signs includes: (6)

Answer 46

¤ Pain ¤ Oedema ¤ Deformation ¤ Abnormal position of the limb ¤ Limb dysfunction ¤ Crepitation

Question 47

Several options exist for fracture stabilization, and numerous factors must be considered when deciding on an appropriate fixation method. Such as: (4)

Answer 47

¤ Patient factors: Size, age, weight, breed, activity level ¤ Client factors: Finances, compliance, husbandry ¤ Fracture factors: Configuration, location, forces, contamination ¤ Veterinarian factors: Understanding of biomechanics and healing, knowledge of particular implants, implant availability

Question 48

Describe conservative fracture tx.

Answer 48

The main aim of conservative treatment method is to restore anatomic position of the the injured limb and ensure the maximal immobility of the fractured area. When conservative treatment method is used, the ends of the fractured bone are only immobilised. No immobilising construction can inflexibly support the bone. There is always soft tissue between the bone and the immobilizer that cannot be pressed too strongly because it may cause oedema, blood supply problems, osteoporosis, and even necrosis.

Question 49

Describe surgical fracture tx.

Answer 49

¤ Assemblage of fractured bone fragments during a surgery is termed osteosynthesis. ¤ Fractured bone ends are assembled via osteosynthesis using various equipment. ¤ Metal constructions enable assembly of bone fragments efficiently and provide them with necessary strength reserve.