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Flashcards in Small animal developmental disease Deck (100)
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1

Outline the aetiopathogenesis of hip dysplasia

- Inherited
- Non-genetic factors play role in expression of disease including body size, growth rate, nutrition, exercise, muscle mass
- Grossly normal at birth
- Loss of congruency between articular surfaces of acetabulum and femoral head, leading to osteoarthritis and remodelling

2

What causes the pain evident in the initial stages of hip dysplasia?

Stretching of the joint capsule and microfractures in the dorsal acetabular rim

3

Explain why the pain experienced in hip dysplasia appears to subside with age

- Gradual increase in stability to due intra- and peri-articular changes (mainly thickening of joint capsule)
- Secondary changes later in life
- As continues to progress, will get pain again as a result of osteoarthritis

4

Outline the diagnosis of hip dysplasia

- Joint laxity (degree of subluxation)
- Norberg-Olsson angle
- Signs of osteoarthritis
- NB poor correlation between the severity of radiographic changes and clinical signs

5

Explain how the Norberg-Olsson angle is used in the diagnosis of hip dysplasia

- Angle between the centre of the femoral head and dorsal edge of the acetabular rim
- Angles smaller than 105˚ are considered abnormal - indicate that femoral head has luxated to some degree out of the acetabulum

6

Describe the signs of osteoarthritis that are commonly seen in the hip as a result of hip dysplasia

- Change in shape of dorsal acetabular edge
- New bone formation in acetabular fossa, cranial and caudal acetabular edges, femoral head and neck
- Degree of remodelling of the femoral head and neck

7

List some differentials for hip dysplasia in young dogs

- Patellar luxation
- Cranial cruciate ligament disease
- hock adn stifle osteochondrosis
- Legg-Calve-Perthes disease
- Septic arthritis
- Spinal disorders
- Myasthenia gravis
- Myopathies

8

List some differential diagnoses for hip dysplasia in mature dogs

- Cranial cruciate ligament disease
- Patellar luxation
- Degenerative lumbosacral disease
- Other spinal disorders
- Achilles tendinopathy
- Septic arthritis

9

What clinical signs would you expect to see in a young dog with hip dysplasia?

- Variable pelvic limb lameness
- Swaying of pelvis when walking
- Bunny hopping at faster speeds
- Weakness of pelvic limbs
- Reluctance to exercise
- Inability to jump
- Inactivity stiffness

10

What clinical signs would you expect to see in an adult dog with hip dysplasia?

- Difficulty rising
- Pelvic limb inactivity stiffness
- Exercise intolerance
- Difficulty jumping
- Behavioural changes e.g. aggression around HLs
- Sudden onset lameness (uncommon)

11

What is the definition of elbow dysplasia in dogs?

Abnormal development of the cubital joint leading to incongruency

12

What are the 3 main diseases causing elbow dysplasia in dogs?

- Ununited anconeal process (UAP)
- Fragmentation of the medial coronoid process (FCP)
- Osteochondritis dissecans (OCD) of the medial portion of the humeral condyle

13

Identify uncommon diseases that may be included within elbow dysplasia in dogs

- Joint incongruity
- Incomplete fusion of the medial epicondyle
- Idiopathic osteoarthritis of the medial compartment of the elbow joint
- Angular limb deformity

14

How may an un-united anconeal process occur?

- Either due to development as a separate centre of ossification
- Or separation secondary to non-traumatic premature closure of the distal ulnar growth plate

15

Which breed is predisposed to the development of an un-united anconeal process as a result of separate centres of ossification?

GSD

16

Which breed is predisposed to the development of an un-united anconeal process as a result of non-traumatic premature closure of the distal ulnar growth plate?

Bassett hound

17

Briefly explain how premature closure of the distal ulnar growth plate leads to an un-united anconeal process

- Ulna does not grow at same rate as the radius, so radius forces heads of humerus caudally
- Puts pressure on anconeal process, preventing fusion
- Radius leads to joint incongruency

18

What are the consequences of an un-united anconeal process?

- Irritation and instability following separation of the anconeal process causing osteoarthritis
- Often seen in association with FCP

19

Which breeds are predisposed to elbow dysplasia as a result of an un-united anconeal process?

- GSD primarily
- Large breed dogs e.g. Wolfhound, Rottweiler, St Bernard, Great Dane

20

Outline the clinical signs of an un-united anconeal process

- Progressive thoracic limb lameness 4-5months of age
- Strange gait with elbow abducted +/- outward rotation of foot
- Palpation/manipulation reveals joint thickening and varying amounts of joint effusion
- Reduced joint movement, pain, maybe crepitus

21

How is an un-united anconeal process diagnosed?

- Fully flexed lateral radiograph of joint
- Arthroscopy possible for evaluation of remainder of joint for FCP and OCD

22

What should be avoided when taking a radiograph in a case with a suspected un-united anconeal process?

Superimposition of medial epicondyle on the olecranon

23

What is the most common cause of elbow lameness in young, rapidly growing dogs of large and giant breeds?

Fragmentation of the medial coronoid process

24

Which breeds are predisposed to a fragmented medial coronoid process?

- Rottweilers
- Labrador retrievers
- Bernese mountain dog
- GSD
- Golden retriever
- St. Bernard
- Chow chow
- Rhodesian ridgeback
- Newfoundland

25

What is the main difference between an FCP and a UAP?

There is no separate centre of ossification for the coronoid process - is a result of fracture of this fragment

26

List the potential causes of a fragmented coronoid process

- Osteochondrosis
- Microfracture/fracture
- Radioulnar incongruity
- Humeroulnar incongruity
- Abnormal pressure on medial coronoid process

27

Outline the consequences of a fragmented coronoid process

- Fragment may have fractured from inner aspect of medial coronoid process immediately adjacent to the radial head, or from apex of the process
- Fragment may project causing irritation of medial humeral condyle (aka kissing lesion)

28

Outline the clinical signs of a fragmented coronoid process

- Outward rotation of foot
- Reduced range of flexion and extension
- Painful response to external rotation and hyperextension
- Crepitus in advanced cases
- Pressure on medial coronoid process elicits strong pain response

29

Outline the diagnosis of a fragmented coronoid process

- Conventional radiography: difficult to see lesion unless large fragment on craniocaudal or craniolateral-caudomedial oblique projections
- CT images better
- Arthroscopy, also for assessment of severity

30

Outline the development of osteochondrosis of the medial condyle

- Lesion initiates within articular epiphyseal cartilage complex in developing joint
- necrosis of vascular channels leads to development of cartilage flap
- Separates from underlying bone, leading to discomfort
- Usually bilateral, on and on outer edge of central weight bearing region of the articular surface of medial portion of humeral condyle