Lecture 5

Question 1

What are the characteristics of Salter-Harris fractures?

Answer 1

-occur in skeletally immature animals less than one year
-usually caused by trauma
-can occur with severe metaphyseal osteopathy or retained cartilaginous core
-types 1 and 2 have a good prognosis
-types 3 and 4 have a poorer prognosis
-type 5 has a guarded prognosis; worst type

Question 2

What are the Roentgen signs of growth plate injuries?

Answer 2

-can be unilateral or bilateral
-affected physis may appear normal initially but then close prematurely
-causes skeletal deformities
-distal ulnar physis commonly affected due to shape

Question 3

What are the Roentgen signs of premature distal ulnar physis closure?

Answer 3

-affected ulna is measurably shorter than other side (unless bilateral)
-styloid process of ulna may be separated from carpus
-cranial and/or medial bowing of radius
-cortical thickening on concave side of radius
-distal radius subluxated craniomedially from radial carpal bone
-manus deviates laterally; carpus valgus
-humero-ulnar joint spaces widens
-radial head luxates laterally (if severe)
-DJD of elbow
-secondary UAP

Question 4

What is shown in this radiograph?

Answer 4

premature distal ulnar physis closure
-bowing of radius

Question 5

What is shown in this radiograph?

Answer 5

widening of humero-ulnar joint space due to premature distal ulnar physis closure

Question 6

What is shown in this radiograph?

Answer 6

widening of humero-ulnar joint and secondary UAP due to premature distal ulnar physis closure

Question 7

What are the Roentgen signs of premature distal radial physis closure?

Answer 7

-shortened length of radius compared to other side (unless bilateral)
-increased radiocarpal joint space
-increased humero-radial joint space
-ulna typically remains straight

Question 8

What is shown in these radiographs?

Answer 8

premature distal radial physis closure
-increased radiocarpal joint space
-increased humero-radial joint space

Question 9

Which physis has closed prematurely in each set of radiographs?

Answer 9

Left: distal ulnar physis
Right: distal radial physis

Question 10

What are the complications of fracture healing?

Answer 10

-malunion
-delayed union
-nonunion; viable or nonviable

Question 11

What are the characteristics of malunion?

Answer 11

-healed but in abnormal anatomic position
-can lead to osteoarthrosis if involving joints
-can be difficult to recognize if they occur in young dogs; bones will undergo extensive remodeling

Question 12

What is shown in this radiograph?

Answer 12

fracture malunion complication

Question 13

What are the characteristics of delayed union?

Answer 13

-fracture is healing but not as quickly as expected
-duration compared to similar fractures and fixation
-subjective assessment since healing depends on many different factors

Question 14

What are the causes of delayed union?

Answer 14

-severe soft tissue damage/poor blood supply
-distracted or overriding fragments
-improper/inadequate reduction or fixation
-significant periosteal stripping
-removal of large bone fragments
-obstruction or destruction of blood supply by implant

Question 15

What are the characteristics of nonunion?

Answer 15

-fracture that has not healed with no evidence of progression to bony union
-healing will not proceed without intervention
-often causes muscle atrophy and lameness
-fragment motion can cause pseudoarthrosis
-distal radius and ulna of small breeds is common site

Question 16

What are the viable types of nonunion?

Answer 16

-hypertrophic
-oligotrophic

Question 17

What are the nonviable types of nonunion?

Answer 17

-dystrophic
-necrotic
-defect
-atrophic

Question 18

What are the characteristics of hypertrophic nonunion?

Answer 18

-excessive lysis at fracture site
-excessive, non-bridging callus formation
-sclerosis of bone fragments
-can have angular limb deformity

Question 19

What are the characteristics of oligotrophic nonunion?

Answer 19

-little to no callus
-bridging of fracture fragments with fibrous tissue
-difficult to differentiate from nonviable nonunions, especially atrophic

Question 20

What is shown in these radiographs?

Answer 20

hypertrophic nonunion
-widening of fracture gap
-excessive, non-bridging callus
-sclerotic fracture ends

Question 21

What is shown in this radiograph?

Answer 21

oligotrophic nonunion
-rounded fracture ends
-sealed medullary cavity of distal fragment
-minimal callus formation

Question 22

What is shown in this radiograph?

Answer 22

defect nonunion
-large fracture gap; callus cannot bridge

Question 23

What is shown in these radiographs?

Answer 23

atrophic nonunion

Question 24

What are the characteristics of degenerative joint disease?

Answer 24

-also known as osteoarthrosis
-degenerative disorder of synovial joints
-slowly progressive condition
-most frequently seen in weight bearing joints

Question 25

What are the Roentgen signs of DJD?

Answer 25

-intracapsular soft tissue swelling -periarticular osteophytes -decreased size of joint space -subchondral sclerosis -subchondral osteolysis -subchondral bone cysts -joint mice; mineralized, intra-articular osseous bodies

Question 26

What is shown in these radiographs?

Answer 26

DJD

Question 27

What is shown in this radiograph?

Answer 27

subchondral osteosclerosis consistent with DJD

Question 28

What is shown in this radiograph?

Answer 28

non-aggressive subchondral osteolysis consistent with DJD

Question 29

What is shown in this radiograph?

Answer 29

joint mouse consistent with DJD

Question 30

What are the characteristics of the cranial cruciate ligament?

Answer 30

-runs from medial aspect of lateral femoral condyle to intercondylar area of tibia -prevents cranial displacement of tibia -limits internal rotation of tibia -prevents hyperextension of stifle

Question 31

What are the characteristics of cranial cruciate ligament rupture?

Answer 31

-more common in females than males -seen in young, athletic dogs and middle age, overweight dogs -causes acute, non-weight bearing lameness

Question 32

What are the Roentgen signs of CCL rupture?

Answer 32

-tibia may be displaced cranially -intracapsular swelling -avulsion fracture in cranial joint space -secondary DJD with osteophytes on patella, adjacent to trochlear groove of femur, and on margins of tibial plateau and fabellae

Question 33

What is shown in this radiograph?

Answer 33

CCL rupture -intracapsular swelling -displacement of infrapatellar fat pat -displacement of fascial planes caudal to joint

Question 34

What is shown in this radiograph?

Answer 34

avulsion fracture secondary to CCL rupture

Question 35

What is shown in this radiograph?

Answer 35

DJD secondary to CCL rupture -osteophytes on patella, near trochlear groove, and on margins of tibial plateau and fabellae

Question 36

What are the characteristics of septic arthritis?

Answer 36

-origins include direct inoculation, extension from soft tissue, or hematogenous -occurs in conjunction with other systemic infections

Question 37

What are the Roentgen signs of septic arthritis?

Answer 37

-severe swelling early in infection -osteolysis and rough/irregular articular margins -multiple joint surfaces involved -severe subchondral erosion -periosteal reaction and osteophytes if chronic

Question 38

What is shown in these radiographs?

Answer 38

septic arthritis

Question 39

What are the possible etiologies of erosive polyarthritis?

Answer 39

-rheumatoid arthritis (most common in dogs) -polyarthritis of greyhounds -periosteal proliferative polyarthropathy (cats)

Question 40

What are the Roentgen signs of erosive polyarthritis?

Answer 40

-intracapsular soft tissue swelling -cyst-like lucencies in subchondral bone -destruction of joint surfaces -narrow joint spaces -subluxation/luxation of joints

Question 41

What is shown in these radiographs?

Answer 41

erosive polyarthritis

Question 42

What are potential etiologies of non-erosive polyarthritis?

Answer 42

-systemic lupus erythematous/SLE (most common) -idiopathic polyarthritis -feline non-erosive polyarthritis -arthritis associated with chronic infection -polyarthritis/polymyositis syndrome -polyarthritis/meningitis syndrome -plasmacytic-lymphocytic synovitis

Question 43

What are the Roentgen signs of non-erosive polyarthritis?

Answer 43

-intracapsular swelling -no osteolysis noted -multiple joints involved -often involves carpus, tarsus, and stifle

Question 44

What is shown in these radiographs?

Answer 44

non-erosive polyarthritis

Question 45

What are the characteristics of joint-associated neoplasia?

Answer 45

-middle aged to older medium to large breed dogs -rare in cats -arise from undifferentiated mesenchymal cells of synovium -commonly in stifle and elbow

Question 46

What are the most common joint-associated neoplasias?

Answer 46

-histiocytic sarcoma -synovial mixoma/mixosarcoma

Question 47

What are the Roentgen signs of joint-associated neoplasia?

Answer 47

-intracapsular and/or extracapsular swelling early on -osteolysis later on which can affect both sides of joint due to bony invasion -metastasis to regional lymph nodes and lungs

Question 48

Which other tumors can affect joints?

Answer 48

-fibrosarcoma -rhabdomyosarcoma -malignant fibrous histiocytoma -poorly differentiated sarcoma

Question 49

What is shown in these radiographs?

Answer 49

joint-associated neoplasia