Musculoskeletal - Joints

Question 1

when is joint stability most stable?

Answer 1

during extension

Question 2

arthrigryposis

Answer 2

abnormal joint positioning - overextension/overflexion
primarily a CNS lesion - congenital absence fo motor neurons to selected muscles leads to atrophy with overextesnion/flexion of unaffected muscle
causes: akabane virus, bluetongue virus, BVDV, hereditary, alkaloid plant toxicity

Question 3

hip dysplasia

Answer 3

lack of conformity between the femoral head and acetabulum -> increased joint laxity and increased chance of subluxation
large and giant breed dogs - developmental abnormality (GSD, labrador)
also cats and cattle

Question 4

elbow dysplasia

Answer 4

developmental abnormality
joint incongruity
pain, lameness and osteoarthritis
young large breed dogs

Question 5

osteochondrosis

Answer 5

aka dyschondroplasia
focal defect of endochondral ossification in the articular-epiphyseal cartilage complex -> ischaemic injury to growing cartilage
(different types according to severity)

Question 6

manifestations of osteochondrosis

Answer 6

osteochondrosis latens = disruption of growth cartilage blood supply causing focal injury and necrosis of growth cartilage (subclinical, has potential to resolve)

osteochondrosis manifesta = retention of necrotic cartilage causing focal delay or failure of endochondral ossification

osteochondrosis dissecans = necrosis dissects through the articular cartilage -> flap (clinically relevant, not reversible)

Question 7

cervical vertebral stenotic myelopathy (Wobbler syndrome)
CVSM

Answer 7

malformation of the cervical vertebrae causing stenosis of the vertebral canal and spinal cord compression
presents as neurologic disease with slow, progressive ataxia
dynamic or static stenosis - dynamic is when the compression only occurs during movement, static is when compression is always occurring

Question 8

primary and secondary degenerative joint disease (DJD)

Answer 8

primary degenerative arthropathy - excessive degeneration in response to normal wear and tear

secondary degenerative arthropathy - primary malformation or injury leading to articular degenrration and secondary bone and joint changes e.g. hip dysplasia, osteochondrosis, cruciate rupture

secondary more common

Question 9

stages of DJD

Answer 9

early - appearance is normal, mild increase in cartilage thickness
mild - superficial erosions, normal or reduced thickness, chondrocyte degeneration, early fibrillation
moderate - locally extensive areas of fibrillation, loss of cartilage integrity
chronic - full thickness cartilage loss with exposure of subchondral bone, joint capsule thickening (synovial hyperplasia), osteophytes

Question 10

e.g. list some processes you may see with DJD

Answer 10

fibrillation, eburnation, osteophytes

Question 11

intervertebral disc disease (IVDD)

Answer 11

progressive mineralisation of the nucleus pulposus
herniation / protrusion of disc material
spondylosis - formation of osteophytes and fusion of adjacent vertebral bodies

Question 12

two types of herniation of disc material
(Hansen)

Answer 12

hansen type 1 = sudden, massive extrusion into spinal cord

hansen type 2 = partial herniation of nucleus pulposus through ruptured annulus fibrosus (slow)

Question 13

diskospondylitis

Answer 13

INFLAMMATORY
inflammation of the vertebrae and the IV discs
commonly caused by bacteria, haematogenous spread

Question 14

inflammatory arthritis

Answer 14

mono-articular - local trauma, penetrating wound, extension from local osteomyelitis
polyarticular - infectious, immune-mediated

Question 15

non-infectious polyarthritis

Answer 15

immune-mediated

erosive/non-erosive

acute/chronic

Question 16

synovitis

Answer 16

inflammation of the synovium of the joint

Acute changes are typically associated with 1) decreased viscosity of synovial fluid 2) increased
turbidity associated with neutrophils and fibrin exudate 3) red/brown discoloration from
haemorrhage and 4) hyperaemic synovium

Chronic changes are typically associated with 1) lymphoplasmacytic inflammation 2) granulation
tissue proliferation and villous hyperplasia 3) joint capsule fibrosis (intra-articular adhesions) 4)
subchondral bone sclerosis or disuse osteopaenia

Question 17

neoplasms in joints

Answer 17

histiocytic sarcoma - dendritic cell of origin, rapidly growing very aggressive, retrievers and labs

synovial sarcoma - commonly recur following excision, large/giant breed dogs in stifle joint

tumour-like lesion - synovial chondromatosis (metaplasia) - multiple nodules of hyaline cartilage in the synovial membrane, may be associated with DJD

Question 18

synovial chondromatosis

Answer 18

not neoplastic
gformation of osseous nodules within joints
pathogenesis isn’t really known

Question 19

what might you see in response to synovial injury?

Answer 19

villous hypertrophy/hyperplasia
pannus formation (hyperproliferation of synovial membrane)
joint capsule thickening (fibrosis)

Question 20

as a joint inflammation progresses, what processes might you see as it becomes chronic

Answer 20

increasing loss of cartilage integrity - eventually full thickness cartilage loss
fibrillation
osteophytes
thickening of subchondral bone
synovial hyperplasia