Test 2: 22: patellas

Question 1

the patella tendon inserts on the

Answer 1

tibial tuberosity

Question 2

what muscles attach to the patella

Answer 2

quadriceps:
rectus femoris from the tuberosity on the ilium
vastus lateralis, vastus medialis, vastus intermedius)- origin on proximal
femur

Question 3

the patella sits in the –

Answer 3

tochlear groove of the femur

Question 4

grade 1 lux patella

Answer 4

in- in

is in, can push it out, then it pops back in on its own

usually no clinical signs

Question 5

grade 2 lux patella

Answer 5

in - out

in on exam, can push it out and then it stays out

nonpainful- skipping lameness: sponatenously luxated

Question 6

skipping lameness is —

Answer 6

grade 2 (in-out) patella lux

Spontaneous luxation occurs and will return to groove

Question 7

grade 3 patella lux

Answer 7

out-in

patella sits outside the groove
can push it into the goove but will spontaneously pop back out

Abnormal ”crouched” gate, often bilateral- (can’t extend the knee cause patella is out)

Question 8

Abnormal ”crouched” gate, often bilateral

Answer 8

grade 3 patella lux
out-in

found out, can push in, but will pop out on its own

(can’t extend the knee cause patella is out)

Question 9

grade 4 patella lux

Answer 9

out out

out and can not push back in cause trochlear groove is gone

Possible severe tibial rotation

Abnormal “crouched” gate, severe lameness and dysfunction of limbs (can’t extend leg, and eventually patella gets pulled to back of leg and acts as flexor → pooping walk)

Question 10

causes of patella luxation

Answer 10

congenital/developmental: do not breed these dogs

trauma

iatrogenic- improper alignment of femur fracture, or improper closure of joint capsule of stifle

Question 11

chances of medial vs lateral patellar lux

Answer 11

medial is most common

but as animal gets bigger the chance of lateral increases

Question 12

Answer 12

1. Coxa vara- hip misshaped
2. Femoral varus and genu varum- femur bowed- knees out
3. Shallow trochlear groove with poorly developed trochlear ridge(s)

Question 13

Answer 13

4. Hypoplasia of the medial femoral condyle (bowed leg)
5. Medial displacement of tibial tuberosity and/or internal rotation of tibia relative to femur

Question 14

Answer 14

6. Proximal tibial varus
7. Internal rotation of the foot,

Question 15

patella lux occurs in what type of dogs

Answer 15

young to middle age

normally small/toy breeds

can be large breed- labs

Question 16

what are some other orthopedic diseases that can occur with patella luxation

Answer 16

CCL tear
hip pain
tarsal instability- can’t extend knee so they will extend ankle to touch the ground

Question 17

what xrays for patella lux

Answer 17

vd and lateral of stifle including whole tibia

one vd of entire femur- may need to sit dog up to get flat picture

Question 18

chronic patella lux causes

Answer 18

Abnormal limb development
Altered limb mechanics
Gait abnormalities/lameness
Abnormal wearing of articular cartilage
osteoarthritis

Question 19

when to do surgery on patella lux

Answer 19

2: only if clinical signs effect quality of life

3 and 4: do surgery to try to stop deformities

Question 20

trochleoplasty

Answer 20

make trochlear ridge in the femur deeper so patella does not pop out

Question 21

TTT

Answer 21

TIBIAL TUBEROSITY TRANSPOSITION

move tibial tuberosity laterally
(where patella tendon inserts)

Question 22

lateral imbrication

Answer 22

overlapping of joint capsule and fascia on opposite side of patella luxation

Question 23

medial retinacular/fascial release

Answer 23

cut through fascia and joint capsule on the same side as patella luxation

releases tension pulling patella in that direction

Question 24

how to prevent internal rotation of the tibia

Answer 24

lateral fabellotibial suture

used to prevent medial lux of patella

Question 25

how to treat medial patella lux in large dog

Answer 25

distal femoral osteotomy (DFO) cut end of femur to correct for curve or twist

may need to TTT to move tibital tuberosity lateral

use lateral fabellotibial suture to prevent internal rotation

Question 26

surgery for patella lux will improve grade by —

Answer 26

2 grades

Question 27

complications of patella lux surgery

Answer 27

re-luxation
implant failure
infection
delayed healing

Question 28

knock knee

Answer 28

genu valgum (knee points in)

lateral patella luxation

Question 29

lateral or medial patella lux are usually more severe

Answer 29

lateral: occurs in younger dogs and more severe

medial: more common

Question 30

Patella alta

Answer 30

patella too high in goove: predisposed to medial patella luxation

Question 31

patella baja

Answer 31

patella too low in the groove
predisposed to lateral patella luxation

Question 32

patella fracture will present as

Answer 32

severe lameness
pain and swelling at cranial stifle joint

Question 33

patellar fracture repair

Answer 33

very difficult- pins and tension band repair
86% failure