Test 2: 22: patellas Flashcards
the patella tendon inserts on the
tibial tuberosity
what muscles attach to the patella
quadriceps:
rectus femoris from the tuberosity on the ilium
vastus lateralis, vastus medialis, vastus intermedius)- origin on proximal
femur
the patella sits in the –
tochlear groove of the femur
grade 1 lux patella
in- in
is in, can push it out, then it pops back in on its own
usually no clinical signs
grade 2 lux patella
in - out
in on exam, can push it out and then it stays out
nonpainful- skipping lameness: sponatenously luxated
skipping lameness is —
grade 2 (in-out) patella lux
Spontaneous luxation occurs and will return to groove
grade 3 patella lux
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)
Abnormal ”crouched” gate, often bilateral
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)
grade 4 patella lux
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)
causes of patella luxation
congenital/developmental: do not breed these dogs
trauma
iatrogenic- improper alignment of femur fracture, or improper closure of joint capsule of stifle
chances of medial vs lateral patellar lux
medial is most common
but as animal gets bigger the chance of lateral increases
- Coxa vara- hip misshaped
- Femoral varus and genu varum- femur bowed- knees out
- Shallow trochlear groove with poorly developed trochlear ridge(s)
- Hypoplasia of the medial femoral condyle (bowed leg)
- Medial displacement of tibial tuberosity and/or internal rotation of tibia relative to femur
- Proximal tibial varus
- Internal rotation of the foot,
patella lux occurs in what type of dogs
young to middle age
normally small/toy breeds
can be large breed- labs
what are some other orthopedic diseases that can occur with patella luxation
CCL tear
hip pain
tarsal instability- can’t extend knee so they will extend ankle to touch the ground
what xrays for patella lux
vd and lateral of stifle including whole tibia
one vd of entire femur- may need to sit dog up to get flat picture
chronic patella lux causes
Abnormal limb development
Altered limb mechanics
Gait abnormalities/lameness
Abnormal wearing of articular cartilage
osteoarthritis
when to do surgery on patella lux
2: only if clinical signs effect quality of life
3 and 4: do surgery to try to stop deformities
trochleoplasty
make trochlear ridge in the femur deeper so patella does not pop out
TTT
TIBIAL TUBEROSITY TRANSPOSITION
move tibial tuberosity laterally
(where patella tendon inserts)
lateral imbrication
overlapping of joint capsule and fascia on opposite side of patella luxation
medial retinacular/fascial release
cut through fascia and joint capsule on the same side as patella luxation
releases tension pulling patella in that direction
how to prevent internal rotation of the tibia
lateral fabellotibial suture
used to prevent medial lux of patella
