Cruciate disease Flashcards
2 cruciates ligs - which one is usually injured?
- Cranial –> usu injured
2. Caudal
what direction does the cranial cruciate ligament run in the stifle?
the same direction you put your hands into your pock
from prox caudal to distal cranial.
what are the CrCL 3 functions?
- prevent cranial displacement of tibia
- limit internal tibial rotation
- prevent stifle hyperextension
what cause CrCL rupture?
- excessive stress on a normal ligament (uncommon)
- normal stress on an abnormal ligament ie. degeneration (most common form)
why do CrCLs degenerate?
- the interior and the central part of the CrCL degenerate w/ age
- occurs earlier and is more severe in larger breed dogs
- DJD
what are the two functional bands of CrCL?
- craniomedial band: taut during flexion + extension
- caudolateral band: only taut during extension
typical presentation of chronic degeneration of CrCL
intermittent lameness typical of OA is seen for several months –> eventually if ignored/not diagnosed lig degen will progress to rupture w/ sudden deteriorate to marked lameness dt complete rupture +/- meniscal damage
Pex findings of chronic progressive degeneration of the cruciate ligament
- lameness
- medial buttress (pathognomonic for cruciate disease)
- muscle atrophy
- periarticular fibrosis
- joint effusion
- +/- crepitus
- decreased ROM stifle
- +/- stifle joint instability (cranial drawer sign/cranial tibial thrust)
typical CrCL degen stance is:
- tripod stance/forward press
what is the positive sit test?
dogs with cruciate disease will commonly avoid sitting squarely w/ full stifle joint flexion, as this if painful –> will sit unevenly and leave the sore stifle joint slightly extended.
cranial drawer is testing for..
passive laxity of the stifle joint
cranial tibial thrust is testing for…
CCL incompetence and stifle joint instability
‘pseudo-physiologic’ test of stifle joint laxity
if the only the craniomedial band of the CrCL is torn will there be cranial drawer?
Not in extension as the caudolateral band is functional during extension
Present in flexion.
if the only the caudolateral band of the CrCL is torn will there be cranial drawer?
No cranial drawer present as craniomedial band functional in extension and flexion
risk of meniscal injury is how many times higher if stifle joint instability exists
> 160times higher
classic radiographic signs of cruciate disease
- osteophytes on distal ple of patella, trochlea ridge, tibial plateau
- joint effusion (compresses radiolucent fat pad)
how do you assess joint effusion in the stifle radiographically?
rule of thumb: there should be no fluid density/radiopacity cranial to a line drawn btwn the long digital extensor fossa of the femur and the cranial edge of the tibial condyle
ddx for cruciate disease
- Other causes of stifle lameness:
- medial patella luxation
- primary/secondary OA
- avulsion of LDE tendon
- CdCruciate lig injury - Other causes of HL lameness
aims of surgical tx of cruciate disease
- stabilise the stifle joint
- diagnose and tx any concurrent meniscal injury
treatment of cruciate disease involves 3 parts
- Surgical resolution/prevention of stifle joint instability/load on cruciate
- Inspection of menisci for damage
- Lifelong OA management
what are two passive stifle joint stabilisation techniques?
- Extracapsular reconstruction - Lateral fabello-tibial suture, lateral fascial imbrication
- Intracapsular reconstruction (rarely ever)
what are the 3 tibial osteotomy surgeries
- Tibial plateau leveling operation
- Triple tibial osteotomy
- Tibial tuberosity advancement
why are medial meniscal injuries more common secondary to cruciate rupture (vs. lateral meniscus)?
- the medial meniscus is firmly attached to the tibial plateau and can not ‘escape’ the shear force of the femoral condyle
- the lateral meniscus is only loosely attached to the tibial plateau, and unlike the medial meniscus is attached to the femoral condyle, so is able to move w/ the femoral condyle instead of being damaged by it
meniscal injury treatment
- ID via exploratory arthrotomy
- remove only damaged parts of meniscus (if entire meniscus damaged - remove all)
total meniscectomy consequences
will promote DJD but leaving a damaged meniscus in situ will cause persistent lameness
which stifle surgery has the best outcomes and complications?
TPLO
what % of cases w/ stifle joint instability have meniscal injury?
60
