Stifle and Femur

Question 1

Landmarks of femur

Answer 1

1. Lateral trochlear ridge
2. Medial trochlear ridge
3. Medial femoral condyle
4. Lateral femoral condyle
5. Intercondylar fossa
6. Extensor fossa-cranial lateral
7. Caudal lateral fossa

Question 2

Patella

Answer 2

Parapatellar fibrocartilage-medial

Question 3

Tibia

Answer 3

1. Medial tibial plateau (condyle)
2. Lateral tibial plateau (condyle)
3. Intercondylar eminence of tibia
   - Medial intercndylar eminence of the tibia
4. Tibial tuberosity

Question 4

Joints

Answer 4

1. femoropatellar
   - suprapatellar pouch
2. Medial femorotibial
   - cranial compartment
   - caudal compartment
3. Lateral femorotibial
   - cranial compartment
   - caudal compartment
   - -proximal
   - -distal

Question 5

Soft tissues (cranial)

Answer 5

1. Patellar ligaments
   - lateral
   - middle
   - medial
2. Parapatellar fat pad
3. Quadriceps femoris muscles
4. Sartorius

Question 6

Soft tissues (caudal)

Answer 6

1. Popliteus muscle
2. Semimembranosus
3. Semitendiosus

Question 7

Soft tissues (medial)

Answer 7

1. Medial collateral ligament
2. Medial femoropatellar ligament
3. Sartorious
4. Gracillus

Question 8

Soft tissues (lateral)

Answer 8

1. Lateral collateral ligament
2. Lateral femoropatellar ligament
3. Insertion of the long digital extensor and peroneus tertius
4. Biceps femoris

Question 9

Intra articular soft tissues

Answer 9

1. Medial and lateral meniscus
2. Cranial cruciate ligament
3. Caudal cruciate ligament
4. Medial and lateral cranial meniscotibial ligaments
5. Medial and lateral caudal meniscotibial ligaments
6. Meniscofemoral ligament (lateral)

Question 10

Common OA sites

Answer 10

1. Medial femorotibial joint
2. Lateral femorotibial joint
3. Femoropatellar joint

Question 11

Common fx or fragment sites

Answer 11

1. Patella
2. Trochlear ridge
3. Medial intercondylar eminence of the tibia
4. Avulsion of insertion of LDE (or PT)
5. Avulsion insertion of Cr cruciate

Question 12

Common site luxation

Answer 12

1. upward fixation of patella (not true luxation)

2. Lateral luxation of patella (rare)

Question 13

Common soft tissue injuries

Answer 13

1. Collateral ligament desmitis, tear/disruption (M > L)
2. Patellar ligament desmitis/tear/disruption
3. Cruciate ligament tear or disruption (Cr > Ca)
4. Meniscal tears

Question 14

Common OC/OCD sites

Answer 14

1. LTR-most common
2. Medial trochlear ridge
3. Patella
4. Osteonecrosis of femoral condyles in foals

Question 15

Subchondral bone cysts

Answer 15

1. Medial femoral condyle
2. Proximal tibia
3. Meniscal cysts

Question 16

Stifle/hock lameness

Answer 16

1. Often bilateral
2. difficulting changing gait
3. bunny hopping
4. squared off toes from dragging foot

Question 17

Most useful radiographic view for femorotibial OA

Answer 17

caudocrania projection

Question 18

earliest radiographic sign of medial femorotibial OA

Answer 18

lipping of medial tibial plateau due to osteophyte formation

Question 19

Other radiographic signs of medial femorotibial OA

Answer 19

1. Osteophyte formation on femoral condyle
2. flattening of condyle
3. areas of sclerosis and/or lysis in subchondral bone of weight bearing regions

Question 20

Joint space narrowing is a sign of

Answer 20

end stage joint disease

-also depends on very careful positioning to determine

Question 21

Best radiographic view for femoropatellar OA

Answer 21

lateral view

Question 22

Earliest/most obvious sign of femoropatellar OA

Answer 22

osteophyte formation of distal patella

Question 23

Etiology patellar fractures

Answer 23

Direct trauma

Question 24

CS patellar fx

Answer 24

1. variable effusion, swelling, lameness

2. May hold limb partially flexed, capable of weight bearing

Question 25

Radiographic view if patellar fx

Answer 25

Standard 3 views + flexed lateral and patellar skyline

Question 26

Patellar fx tx conservative

Answer 26

stall rest 2-3 mos | -patellar base fx doesn't require sx

Question 27

Patellar fx removal

Answer 27

- Arthroscopy preferred (can also visualize trochlear ridges) - Can remove up to 1/3 of patella if medial saggital slab fracture

Question 28

Patellar fx fixation

Answer 28

Can use lag screws or small plates Crit fixation 1. complete disruption quadriceps apparatus 2. fx gap > 5mm 3. Malalignment articular surface 4. Unstable fragments palpable through skin

Question 29

Patellar fx prog

Answer 29

Frag rem saggital fx-80-100% full athletic fxn | Disruption quad app-guarded for athlete

Question 30

Trochlear ridge fractures

Answer 30

- Direct trauma - mod-severe lameness, effusion, swelling - crepitus/external wounds possible - possiblity for joint sepsis - tx arthroscopic rem frags - prog good, non-weight bearing

Question 31

Fx of medial intercondylar eminence of tibia

Answer 31

- not usually avulsion fractures - best radiographic views for dx are caudocranial and flexed lateromedial - removal salal frags - prognosis good, more dependent on soft tissue injuries

Question 32

Avulsion fx of long digital extensor tendon or peroneus tertius

Answer 32

- share common origin in extensor sulcus, lateral to distal aspect of lateral trochlear ridge of femur - most common foals and young horses - typically after forced hyperextension of the hindlimb - dx rads, tx rem frags and rest - prog-poor

Question 33

Avulsion fx cranial cruciate ligament

Answer 33

rare

Question 34

Lateral patellar lux

Answer 34

rare

Question 35

soft tissue injury

Answer 35

dx: MRI, likely underdiagnosed

Question 36

Collateral ligament injury

Answer 36

- u/s common method diagnosis | - complete disruptions or concurrent meniscal/cranial cruciate injury has poor prog

Question 37

Patellar ligament injury

Answer 37

- jumpers are overrepresented - partial or no response to block - u/s diagnostic method of choice - not sure of prognosis

Question 38

Cruciate ligament injury

Answer 38

uncommon | prognosis poor if joint instability

Question 39

Meniscal injury

Answer 39

Most common soft tissue injury of the stifle (medial meniscus) -insidious onset

Question 40

CS meniscal injury grades

Answer 40

G1: longitudinal tear cranial horn and meniscotibial ligament with minimal separation -63% return to work G2: Same as grade 1 with greater tissue separation -56% return to work G3: Tears extend beneath femoral condyle and cannot be viewed in their entirety -5% return to work

Question 41

Meniscal injury tx

Answer 41

``` Arthroscopic debridement (partial menisectomy) Prolonged rest (6 months) ```

Question 42

Factors that decrease prognosis for meniscal injury

Answer 42

1. Articular cartilage damage 2. Concurrent soft tissue injuries 3. Concurrent subchondral bone cyst 4. Dystrophic mineralization of meniscus

Question 43

Osteonecrosis of medial femoral condyle

Answer 43

rare | only in foals

Question 44

Subchondral bone cysts

Answer 44

Common lesion of stifle, second to | -OC/OCD

Question 45

Etiology of subchondral bone cysts

Answer 45

``` age 1-3 MFC most common site Other sites -proximal tibia -LCF -patella ```

Question 46

suchondral bone cysts CS

Answer 46

Asymptomatic-prepurchase rads May be unilateral or bilateral variable response to hind limb flexion variable response to diagnostic anesthesia

Question 47

Subchondral bone cysts rads

Answer 47

1. Caudocranial and flexed lateral most useful - also take caudolateral-craniomedial oblique 2. ALWAYS take contralateral if lesion id'd

Question 48

Femur fx rads

Answer 48

- Under general anesthesia | - Mediolateral and craniocaudal views

Question 49

Femur fx U/S

Answer 49

- First line dx method adults - Can be done standing - Cannot assess configuration