Common causes hindlimb lameness: Stifle

Question 1

What is always a key differential for hindlimb lameness in SA?

Answer 1

cranial cruciate ligament disease

rare in cars
2-10y most common

Question 2

Where is the cruciate ligament, what is the origin/insertion?

Answer 2

intra-articular but extra-synovial

O: caudomedial aspect of lateral femoral condyle
I: cranial intercondylar area of the tibia

Question 3

What are the 3 types of cranial cruciate ruptures?

Answer 3

traumatic avulsion (yank a piece of bone attached to ligament) - uncommon

traumatic rupture - very uncommon

degenerative weakening

Question 4

What is the importance of the cranial cruciate ligament?

Answer 4

role: knee stability

craniotibial translation
internal rotation

Question 5

What do we see in 1/3 of dogs with cranial cruciate ligament disease?

Answer 5

damage to meniscus, 50% dogs have complete rupture
medial meniscus

painful on stifle extension!
best managed by surgical resection

Question 6

What are the menisci?

Answer 6

2 C shaped fibrocartilage pads (medial and lateral)

load bearing/shock absorbing
collagen fiber arrangement converts compression into tension

Question 7

Where are the stifle menisci attached?

Answer 7

medial to tibia
lateral to femur

Question 8

What makes menisci disease difficult?

Answer 8

blood supply only in outer rim = poor healing
good nervous innervation = PAINFUL

Question 9

What do we look for when assessing if a patient is lame in a hindlimb?

Answer 9

Calcaneal dip: Sinks on Sound
Hip hike: Lifts on Lame

Question 10

What should we assess in a stifle examination?

Answer 10

effusion
medial buttress
patellar tracking
crepitus (ROM)
+/- pain
stability tests

Question 11

What is the most reliable stability stifle test and how is it performed?

Answer 11

cranial draw

grip tightly on to bone patella-back femur and tibial crest - back tibia

standing or lateral

Question 12

How do we perform the tibial thrust?

Answer 12

less reliable, well tolerated in conscious animals, easier in bigger dogs, simulates walking

hand over femur, finger over patella, push up paw
should feel finger being pushed forward: when jumps forward its abnormal

Question 13

What is the conservative management/ treatment for cruciate ligament disease?

Answer 13

None really
maybe for dogs less than 15kg
no response in 8 weeks = surgical stabilisation
if meniscal injury it requires surgical tx

Question 14

What is the role of cranial cruciate ligament surgery?

Answer 14

to stabilise the joint
stop/reduce tibial thrust

will not stop the progression of osteoarthritis

Question 15

What are the 3 types of CCL surgeries?

Answer 15

intra-articular
extra-articular
osteotomy techniques

whatever is chosen: MENISCAL INSPECTION IS MANDATORY since over 50% of CCL ruptures have meniscal damage

Question 16

What is the goal of extra-articular CCL surgery?

Answer 16

stops instability whilst fibrosis develops which is what will permanently stabilise the joint since the suture will always snap

Question 17

What is the principle of osteotomy techniques for CCL surgery?

Answer 17

Femoral condyle is a ball rolling down the slope of the tibial plateau = unstable
flatten slope = stable knee

neutralises tibial thrust but the cranial draw test would stay positive

Question 18

What are te 2 most common osteotomy techniques for CCL surgery?

Answer 18

TPLO: tibial plateau levelling osteotomy
TTA: tibial tuberosity advancement

Question 19

What is the prognosis for dogs with CCL tears?

Answer 19

around 50% get bilateral rupture in 2 years
90% dogs get to 90% of pre-rupture activity post surgery

OA will progress irrespective but doesn’t always mean lame
generally good outcomes

Question 20

What surgical technique is superior for CCL tears?

Answer 20

TPLO > TTA = Extrascapular > Intrascapular

Question 21

How does the patella function?

Question 22

How do patellar luxations usually arise?

Answer 22

developmental not congenital
usually medial

Question 23

What can cause patellar luxations?

Answer 23

problems with correct quadriceps mechanism development (possibly from hip/femoral development)

uneven pressure on physes (alteration growth dynamics)

boney deformation follows (lateral bow distal stifle, compensatory deviation tibia, skeletal torsion/angular deformities)

groove development needs pressure: affects depth and alignment during development

Question 24

What is the signalment for patellar luxation?

Answer 24

common cause of intermittent lameness in small dogs usually quite young

occurs in cats but often not clinical

Question 25

What is the clinical presentation for patellar luxations?

Answer 25

classical: intermittent non-weight bearing significant periods of normal, the “skipping” lamness

collapse episodes
abnormal gait/holding limb rotated in severe
chronic lameness

Question 26

What should the orthopaedic examination on a patellar luxation look like?

Answer 26

standing
- no neuro deficits
- comfortable hips
- tarsi ok, comformtable tarsus no instability
- stifle: alignment of patellar feels ok or abnormal
- no tibial thrust/cranial draw
- minimal effusion
- +/- muscle atrophy/ joint effusion

Question 27

How do we examine the patella?

Answer 27

Palpate limb standing
determine alignment: tibial crest-patella ligament - patella

work out where the patella is at rest: IN vs OUT

medial luxation: may have genu vara (bow legged) +/- stifle hyperflexed
lateral luxation: may have genu valga (knock kneed) +/- stifle hyperflexed

walk a few steps and repeat
lateral recumbency, stifle extended, patella manipulated medially and laterally for laxity
flex and extend stifle with rotation and manipulate patella

Question 28

How can we assess pain on luxation/retropatellar pain?

Answer 28

push patellar deep into groove
may help surgical decision making
indicate severity of change/damage

Question 29

What are the 4 grades of patellar luxation?

Answer 29

1: patella IN, returns in automatically (incidental)
2: patella IN, stays out (spontaneous)
3: patella OUT, can be returned into groove (abnormal stifle function)
4: patella OUT, can’t be returned into groove (lameness with crouched stance/gait)

Question 30

How helpful are radiographs for patellar luxation?

Answer 30

they could be normal
clinical palpation is most important diagnostic

could document bone deformities, OA, effusion, etc
help with surgical planning

Question 31

What are the criteria ofr patellar luxation surgery?

Answer 31

not simply grade but grade influences prognosis
make global view on clinical impact, may not influence progression of oA, talk to the owner
is there a clinical problem? lameness? frequency? pain? OA?
20% complication rate with patellar luxation surgery

Question 32

What patellar luxation cases are NON-surgical?

Answer 32

incidentally identified low grade (1 or 2) with no lamness, no discomfort on patella manipulation/retropatellar pressure, happy life

highly infrequent skipping lameness (once a month) may benefit from physiotherapy: improving quadriceps mechanism = patellar stability

Question 33

What patellar luxation cases are surgical?

Answer 33

+/- all grade 4 and 3s

any mild patella luxation 2 with pain on manipulation, retropatellar pressure pain, frequent intermittent lameness (weekly), consistent lameness

Question 34

What are the 4 procedures that can deepen the patellar groove?

Answer 34

trochleoplasty
chondroplasty
wedge recession sulcoplasty
block recession sulcoplasty

Question 35

What is a tibial tuberosity transposition and when is it used?

Answer 35

intra-operative assessment - post trochleoplasty: straighten femur and tibia, flex/extend stifle

a deviated patellar tendon suggests needs transposition
re-aligned bone stabilised with pin and tension band wire

Question 36

How do we manage severe patellar luxations in skeletally immature animals?

Answer 36

ideally wait over 10months
or 2 stage: trochleoplasty + soft tissue augmentation and later TTT

severe luxation could cause more skeletal abnormalities but tibial tuberosity transposition in young could lead to abnormal distal positioning of the insertion of the patellar tendon