Ortho cruciate disease Flashcards
WHat is the aetiology of cranial cruciate ligament disease in dogs vs cats
In dogs tends to be young, healthy dogs with no trauma
Cats tend to be older, overweight or with trauma to pelvic limb; less common
Why should we always check for CCL failure in pelvic limb lameness cases
Often missed; i.e 1/3 of dogs referred for hip dysplasia actually had CCL failure as main reason for lameness
Origin and insertion of cranial cruciate
Caudo-medial part of lateral femoral condyle
Travels across stifle craniomedially to intercondylar fossa of tibia
3 functions of the cranial cruciate ligament
1) Prevents cranial translation of the tibia relative to the femur
2) Prevents internal rotation of the tibia
3) Prevents hyperextension
What are the two functional bands of the CCL and when are they taut
Cranio-medial bend: taut in flexion and extension
Caudo-lateral band: taut in extension only
WHat do we see with partial tear just rupturing caudo-lateral band
Dog is lame
But may not feel any instability because the other band is taut in flexion and extension still
What do we see with partial tear of the craniomedial band of CLL
Lameness
Instability during flexion i.e cranial draw
Why must we test the stifle in flexion and extension for instability
Because if there is a partial rupture, just tearing craniomedial band will just see draw during flexion
What is the meniscus of the joint and what is their function
C shaped cartilages sitting on top of tibia to act as shock absorbers for femoral condyle
- Absorb energy and transmit load
- Functional in lubrication
- Allows joint congruity
What is the difference between the medial and lateral meniscus of the stifle and what implication does this have for damage
Medial meniscus is held in place on medial and cranial aspect (i.e around periphery)
vs lateral only held in place on cranial aspect
when femur/tibia move independently in CCL rupture, femoral condyles slide across the menisci
- On the lateral side, lateral meniscus pushed out the way so not damaged
- vs on medial side, stuck in place so get damage
What is the most common cause of cranial cruciate disease
Progressive degeneration of unknown cause
i.e in dogs it is relatively normal forces across an ABNORMAL ligament
[can also get traumatic causes but rarer]
Characteristics of CCL disease in dogs
Degenerative
Mostly middle aged; typically large breed e.g lab, golden retriver, boxer, rotties etc also westies
~10% bilateral
Often already have some osteoarthritis present
May just be a partial tear so can present as very lame and painful but stable
Why are westies prone to CCL disease despite not being a large breed
Because they are have a very steep tibial plateau which puts abnormal strain on the joint
What happens to those which are only unilateral CCL disease at presentation
~ half of them have rupture of the other one in 6 months after
Presenting signs of CCL disease
Pelvic limb lameness
Can be chronic variable or acute in onset because after long period of degeneration, a mild trauma causes rupture
Difficulty sitting/rising
Initially improve with rest and NSAIDs but then lameness returns with exercise
= Pain and mechanical lameness
WHat is the sit test for CCL failure
Where an animal sits with one leg tucked under normally but the other out to the side
Physical exam findings with CCL disease
Lameness
Sitting with one leg out to side
Medial buttress
Stifle effusion
Quardiceps atrophy
Joint pain during tests
Failure of cranial draw/tibial thrust
What is a medial buttress in CCL disease
Where there is development of fibrous tissue on the medial aspect of the joint in an attempt to stabilise it
Feel thickening + see on radiograph
Where do we feel stifle effusion
Along patellar ligament; will no longer be able to get fingers around it
Cranial draw test basic
Hold femur still and attempt to move tibia cranially; should NOT be able to do this
Out of cranial draw and tibial thrust which is easier to feel in conscious dogs
Cranial draw
Tibial thrust test basic
Compressing tibia against stifle and flexing tarsus
If ligament is intact, the tibial tuberosity should not move but with CCL rupture, will move forward
more subtle
What two radiographic views do we use for CCL evaluation
Mediolateral stifle
Dorsopalmar
Radiographic signs with CCL disease
Stifle effusion; fat pad displacement, disruption of caudal fascial plane
Osteophytes in typical locations; poles of patella, caudal tibial plateau, fabellae, CCL insertion
[may notice cranial displacement of tibia]
Why is meniscal injury bad and how often do we see in with CCL disease
Because meniscus cannot heal so get impact on shock absorption system forever
~1/3 of dogs show this (almost always medial meniscus affected)
Presentation with a secondary meniscal injury after CCL disease
Chronic history of lameness then sudden deterioration
More lame than the average CCL patient
Large stible effusion
Owners may report hearing clicking/popping sound as meniscus released
NB: can happen after CCL surgery
Risk factors for medial meniscal injury
much more likely with complete rupture i.e more instability
More likely with more weeks of lameness i.e left unresolved
More likely if overweight
What does conservative CCL treatment mean
Strict rest for 6-8 weeks + rehab
Want to let body form a scar around the damaged joint which can help stabilise it
Much more successful for small dogs but still poor
Broad categories of surgery for CCL
Intra-articular; to replace ligament
Extra-capsular; to stabilise stifle
Osteotomy; to change joint shape
How does the lateral (febello-tibial retinacular) suture work for CCL
= an extra-capsular method of stifle stabilisation
Use strong permanent suture i.e strong nylon anchored at most isometric points possible to maintain tension throughout range of motion
Want to hold joint still for long enough to get tight periarticular fibrosis
What are some complications/limitations with lateral suture technique
No point combos give constant suture tension; if tightening it in flexion can get instability on extension etc
Ideally perform tightening with stifle in slight extension
What are the main types of osteotomy for CCL
Tibial plateau levelling osteotomy TPLO
Tibial tuberosity advancement TTA
[others are cranial closing wedge osteotomy, triple tibial osteotomt)
How does a TPLO work basic
Cut prox tibia, rotate and secure to change slope angle from 24 degrees to 6 degress i.e flatten it
This will reduce tibial thrust instability
[NB: still have cranial draw since joint unstable; get DYNAMIC stability during movement]
How does TTA work basic
Advance the tibial tuberosity cranially
This makes the force of the patella tendon parallel to loading force of joint; counteracts tibial thrust
i.e slope the same but force has changed
Potential issue = underadvancement of tuberosity
When is TPLO particularly a good idea
Boisterous large dog
Bilateral disease
Steep anlge
POst-op care for TPLO/TTA
6 weeks strict rest
No runningjumping etc
Radiographs at 6 weeks
Gradual return to exercise and physio
