Lecture 9

Question 1

What are the characteristics of tarsal bone collapse?

Answer 1

-analogous to cuboidal bone disease in carpus
-seen in neonatal foals, older foals, or young adults
-tarsal bones are immature and rounded with granular opacity
-excessive flexion of hock and tarsus valgus occur

Question 2

What happens if tarsal bone collapse is not recognized early?

Answer 2

-weight-bearing causes compression of third and central tarsal bones
-compressed bones become wedge-shaped
-fragmentation possible

Question 3

What is shown in these images?

Answer 3

tarsal bone collapse; early stage

Question 4

What is shown in this image?

Answer 4

consequences of tarsal bone collapse:
-narrow joint spaces
-abnormal shape of tarsal bones

Question 5

What is osteochondrosis of the tarsus associated with?

Answer 5

effusion of the talocrural joint

Question 6

What are the typical locations of osteochondrosis in the tarsus?

Answer 6

-intermediate ridge of tibia
-trochlear ridges of talus (L > M)
-medial malleolus of tibia
-calcaneus
often bilaterial

Question 7

What is shown in this image?

Answer 7

osteochondrosis at intermediate ridge of tibia (DIRT)

Question 8

What is shown in these images?

Answer 8

osteochondrosis/OCD at intermediate ridge of tibia (DIRT)
-visible fragment

Question 9

What is shown in this image?

Answer 9

OCD of lateral trochlear ridge of talus with mineralized fragment

Question 10

What is shown in these images?

Answer 10

Left: osteochondrosis of lateral trochlear ridge of talus
-“missing” bone that is cartilaginous instead of mineralized

Right: osteochondrosis of lateral trochlear ridge of talus
-lesion is the divot seen on lateral trochlear ridge
-red arrow is pointing to normal variation of the medial trochlear ridge

Question 11

What is shown in this image?

Answer 11

OCD and reattachment of fragment to medial malleolus of tibia

Question 12

What are the characteristics of DJD in the tarsus?

Answer 12

-aka “spavin”
-periarticular osteophyte and entheseophyte production
-joint space narrowing and collapse
-subchondral sclerosis and lysis
-end result is ankylosis

Question 13

What are the typical locations for DJD in the tarsus?

Answer 13

-tarsometatarsal joint
-distal intertarsal joint
-proximal intertarsal joint (less common)
often bilateral

Question 14

Why is talocrural joint distention seen with DJD of the proximal intertarsal joint?

Answer 14

communication between the two joints leads to the distention

Question 15

What is the importance of the presence of a spur on dorsoproximal MT3?

Answer 15

-may be an entheseophyte on the insertion of the cranial tibial tendon or dorsal tarsometatarsal ligament
-may not reflect DJD if there are no other changes in the joint

Question 16

What is shown in this image?

Answer 16

entheseophyte on the insertion of the cranial tibial tendon or dorsal tarsometatarsal ligament

Question 17

What is shown in these images?

Answer 17

tarsal DJD
-fuzzy, ill-defined joint spaces
-bone production

Question 18

What is shown in these images?

Answer 18

tarsal DJD
-abnormal joint spaces with bone production

Question 19

What is seen in this DMPLO?

Answer 19

tarsal DJD
-abnormal joint space and bone production

Question 20

What is shown in these images?

Answer 20

joint ankylosis as a result of DJD

Question 21

What is shown in these images?

Answer 21

Left: DJD of talocalcaneal joint
Right: normal talocalcaneal joint

Question 22

Why are tarsal fractures difficult to identify?

Answer 22

-complex anatomy
-minimal displacement due to support from intertarsal and collateral ligaments

Question 23

What is shown in this image?

Answer 23

talus fracture and lots of swelling surrounding tarsus

Question 24

What is shown in these images?

Answer 24

osteomyelitis within tarsus

Question 25

What are the common locations for stifle osteochondrosis?

Answer 25

-lateral trochlear ridge of femur (most common) -medial trochlear ridge of femur -articular surface of patella (worst prognosis) -medial femoral condyle (osseous cyst-like lesion) *often bilateral*

Question 26

What is shown in this image?

Answer 26

osteochondrosis lesion on lateral trochlear ridge of femur

Question 27

What is shown in this image?

Answer 27

osteochondrosis lesion on lateral trochlear ridge of femur

Question 28

What is shown in this image?

Answer 28

osteochondrosis lesion on medial trochlear ridge of femur

Question 29

What is shown in this image?

Answer 29

-very large osteochondrosis lesion on lateral trochlear ridge of femur -lots of swelling surrounding joint

Question 30

What is shown in this image?

Answer 30

osteochondrosis lesion on patella with a corresponding trochlear ridge lesion

Question 31

What are the characteristics of osseous cyst-like lesions?

Answer 31

-part of OCD complex -medial femoral condyle most common location -seen in lateral femoral condyle as well -also seen on proximal tibial epiphysis; more rare

Question 32

What is shown in these images?

Answer 32

Left: osseous cyst-like lesion, lysis, DJD, and fragmentation Right: osseous cyst-like lesion, flattening of condyle, DJD (less so than left image)

Question 33

What is shown in this image?

Answer 33

osseous cyst-like lesion with communication with joint space

Question 34

What is shown in these images?

Answer 34

DJD within stifle joint

Question 35

What are the characteristics of lateral patellar luxation?

Answer 35

-seen in miniature horses and foals -malformed trochlear ridges predispose -rads used for diagnosis

Question 36

What are the characteristics of intermittent upward fixation of patella?

Answer 36

-radiographs of little value -patella gets stuck on lateral trochlear ridge -can see remodeling of cranial surface of patella, fragmentation, and entheseophytes after medial patellar ligament desmotomy

Question 37

What is shown in these images?

Answer 37

lateral patellar luxation

Question 38

What are the characteristics of septic arthritis and osteomyelitis?

Answer 38

-most common in young foals -multiple joints affected due to hematogenous spread in foals -if seen in adults, associated with trauma or iatrogenic cause

Question 39

What are the signs of septic arthritis and osteomyleitis?

Answer 39

-periarticular soft tissue swelling -joint distention -irregular outline of subchondral bone -lysis of subchondral bone +/- sclerosis -partial subchondral bone collapse -secondary osteophyte formation

Question 40

What is shown in these images?

Answer 40

physeal septic arthritis and osteomyelitis -lots of swelling

Question 41

What is shown in these images?

Answer 41

physeal septic arthritis and osteomyelitis -more focal lesion -asymmetrical swelling

Question 42

What is shown in these images?

Answer 42

very severe physeal septic arthritis and osteomyelitis -lots of swelling -lots of aggressive lytic changes

Question 43

What is shown in these images?

Answer 43

epiphyseal septic arthritis and osteomyelitis -lots of swelling -destruction of joint space -lots of fragmentation -gas pockets

Question 44

What is shown in this image?

Answer 44

synovial septic arthritis and osteomyelitis -severe swelling -no osseous abnormality

Question 45

What is shown in these images?

Answer 45

synovial septic arthritis and osteomyelitis