Juvenile musculoskeletal Disease

Question 1

Radiographic Opacities

Answer 1

Air → fat → ST and fluid → bone → metal
lucent to opaque

Question 2

Degenerative Joint Disease (DJD)

Answer 2

Osteroarthritis/ osteoarthrosis
Common: intra-capsular ST, osteophytes, enthesophytes

Question 3

Osteophytes

Answer 3

Physiologic attempt to stabilize joint
Outgrowth of the bone at the margin of the articular surface (within joint capsule)

Question 4

Osteophytes pathophysiology

Answer 4

Abnormal joint cartilage loading → cartilage wear/loss → development of osteophytes

Question 5

Enthesis

Answer 5

Origin or insertion of a tendon, ligament or joint capsule to bone

Question 6

Enthesophytes

Answer 6

New bone formation at the enthesis
Secondary to chr. strain, trauma or previous avulsion

Question 7

Juvenile musculoskeletal classifications

Answer 7

Osteochondrosis
Panosteitis
Hypertrophic osteodystrophy
Elbow/ hip dysplasia

Question 8

Acquired musculoskeletal classifications

Answer 8

Fractures
Neoplasia

Question 9

Osteochondrosis (OC)

Answer 9

Abnormal endochondral ossification → thickened cartilage that’s susceptible to injury
Commonly leads to DJD

Question 10

Signalment of dogs with OC

Answer 10

Young rapidly growing large breed dogs

Question 11

Radiographic findings of OC

Answer 11

Flattening of subchondral bone
Surrounding subchondral bone sclerosis
Mineralized cartilage flap (Joint mouse)
Kissing lesion
Joint effusion

Question 12

Osteochondritis Dissecans (OCD)

Answer 12

Separation of the abnormal flap of cartilage from the subchondral bone

Question 13

OC v OCD

Answer 13

OCD: usually cannot determine from survey rads and mineralized cartilage flaps ARE seen

Question 14

Common sites for OC

Answer 14

Shoulder (cd femoral head)
Elbow (medial aspect of humeral condyle)
Stifle (Lateral femoral condyle)
Taurus (medial ridge of talus)

Question 15

Panosteitis

Answer 15

Self-limiting dz
Affects the bones of young, large breed dogs (shepherds, danes, rotties, labs, retrievers)
Males most commonly affected

Question 16

Early rad findings of panosteitis

Answer 16

↑ intramedullary opacity (diaphysis near nutrient foramen)
Blurring of trabecular pattern
Medullary opacities delineated (patchy sclerosis)
smooth periosteal reaction

Question 17

Hypertrophic Osteodystrophy (HOD)

Answer 17

Long bones affected in large rapidly growing dogs
Self-limiting, if severe → premature physeal closure

Question 18

Radiographic findings of HOD

Answer 18

Bilaterally symmetrical lesions
Commonly affects the metaphyses of the distal radius, ulna and tibia

Question 18

Early stage of HOD

Answer 18

ST swelling adjacent to physis
Linear irregular lysis adjacent and parallel to physis (double physis signs)

Question 19

Intermediate stage of HOD

Answer 19

Marked metaphyseal periosteal reaction due to sub-periosteal hemorrhage

Question 20

Late stage of HOD

Answer 20

Periosteal new bone blends with cortex and remodels to normal shape

Question 21

Retained Cartilage Core

Answer 21

Disruption of normal endochondral
Temporary inadequate blood supply to metaphysis → central core of cartilage not transformed to bone

Question 22

Where is retained cartilage core most common?

Answer 22

Large breeds
Incidental finding (distal ulna metaphysis)

Question 23

Radiographic findings of retained cartilage core

Answer 23

Cone-shaped radiolucent area
Narrow zone of adjacent sclerosis

Question 24

What are the developmental conditions of elbow dysplasia

Answer 24

Ununited anconeal process (UAP) Fragmented medial coronoid process Osteochondrosis of the medial humeral condyle Joint incongruity (asynchronous growth of radius/ ulna) *all 4 don't have to be present, + DJD, usually bilat*

Question 25

Radiographic findings of Ununited anconeal process

Answer 25

Radiolucent between anconeal process and olecranon in dogs older than 5m DJD present

Question 26

Fragmented Medial Coronoid Process (FMCP)

Answer 26

Most common developmental disorder (bilat) Degenerative changes and no evidence of UAP or OC Difficult to visualize fragment on rads (CT needed)

Question 27

Sometimes the cranially displaced fragment of FMCP is found on the __________ view

Answer 27

Lateral

Question 28

Radius/ ulna normal growth

Answer 28

Ulna has only one physis distal to the elbow (predisposed to damage), radius has 2 Growth from ulna physis must equal the growth from both radial physes

Question 29

Possible sequelae to premature closure of the ulnar physis

Answer 29

Humeroulnar subluxation Radius curved (bowed radius)

Question 30

Whys is the distal ulnar physis susceptible to trauma?

Answer 30

Conical shape

Question 31

How do you tx the asynchronous growth of radius/ ulna

Answer 31

Ulnar osteotomy *cuts through ulna releasing pressure then IM pen placed → radius grows and straightens up*

Question 32

Hip dysplasia

Answer 32

Abnormal development of the coxofemoral joints → DJD Large breeds, bilat and inherited

Question 33

Normal femoral head

Answer 33

Articular margin between the acetabulum and femoral head should be parallel 50% of head covered by acetabulum Femoral neck narrower than head with smooth margin

Question 34

What are the big things found with hip dysplasia

Answer 34

Acetabular coverage Congruity along cr. 1/3 of joint DJD

Question 35

Radiographic findings of hip dysplasia

Answer 35

Morgan line Thickening of head and neck 2nd to osteophytosis Osteophytosis of the cr. and cd. acetabular rim Flattening/ Sclerosis of acetabulum Subluxation of coxofemoral joint

Question 36

Morgan line

Answer 36

Cd. curvilinear enthesophyte Early indicator of osteoarthosis secondary to coxofemoral joint laxity

Question 37

Other names for Avascular necrosis of the femoral head

Answer 37

Aseptic necrosis or legg-calve-perthes dz Loss of blood supply to the proximal epiphysis

Question 38

Signalment of avascular necrosis of the femoral head

Answer 38

Mini and toy breeds 4-11m Bilat (less than 50% of the time)

Question 39

Early rad findings of avascular necrosis of the femoral head

Answer 39

↑ radiolucency of the femoral head

Question 40

Later rads findings of avascular necrosis of the femoral head

Answer 40

↑ joint space width Flattening/ collapse of the femoral head Shortening and widening of the femoral neck Secondary DJD

Question 41

Patellar luxation

Answer 41

Small breeds Medial: congential/ developmental, small breeds Lateral: rare