Lecture 9: Cranial Cruciate Ligament Injury/Dx III (Exam 2) Flashcards
What is involved for extracapsular reconstruction
Placement of sutures outside the joint or redirections of the lateral collateral lig
What significantly effects the isometry of the joint? What does it affect?
- Location of the origin & insertion of the extracapsular suture
- Affects the amount of drawer motion throughout norm range of motion of the stifle
What can extracapsular sutures also be secured from
- Bone Anchors
- Bone Tunnels
What materials are used in extracapsular sutures
- Monofilament nylon or fishing/leader line
- Manufactured ortho wire
- Braided ortho suture
In extracapsular reconstruction how are sutures tied/connected
W/ a crimp to alter the biomechanical props of the loop
What is this
What is this showing
Tightrope stabilization
What is the true imbrication tech
- Performed by tightening fascia lata
- Usually in addition to another tech
What is the function of the cranial cruciate lig
Passive constraint to the cranial tibial translation & internal rotation of the tibia
What occurs if there is a larger tibial plateau angle
The greater the cranial force there is on the tibia during wgt bearing
Describe the vector force that occurs in the tarsus
- Sum of resulting forces of wt bearing
- Creates a simultaneous force through the patellar ligament & stabilizes the stifle
What happens if the slope of the tibial plateau is NOT anatomically oriented perpendicular to the patellar lig on wt bearing
- Caused tibiofemoral shear force that causes a cranial tibial thrust force (CTT) in the direction of the cranial drawer or tibial translation
- CCT force is accommodated for an in norm animal by the CCL
What happens when the tibia is loaded
- Caudally directed slope of the tibial plateau results in a shear force
- Creates abnorm tibial translation in CCL deficient stifle joints
What is the cranial tibial thrust (CTT)
The shear component of compressive force (normally passively constrained by the CCL)
T/F: CTT is inproportional to the slope of the cranial tibial plateau
False they are proportional
What happens if the tibial plateau slope is reduced
The tibial thrust changes from a cranioproximal direction to a neutral or caudal direction
What causes increase reliance on the caudal cruciate lig
A point where tibial thrust changes direction to a caudal thrust
What is the intent of the tibial plateau leveling osteotomy (TPLO) sx
- Attain a tibial plateau slope of approx 5 to 7 degrees
- Where tibial thrust can be controlled by the caudal cruciate lig & active constraints of the stifle (the quad musces)
What is a “Pivot Shift”
Failure to control internal rotation resulting in drawer w/ internal rotation
Who is TPLO preferred for txing
- Larger active dogs
- Long term rehab & post op control is diff
What is this showing
What is this showing
What is this Xray showing
Before & after of an AP TPLO
What is associated w/ complications of the stifle extensor mechanism
Lower osteotomy results in change of the relative position of the tibial crest
What is an Tibial Wedge Osteotomy (TWO)
A technique for management of the CCLR & increased TPA in young dogs w/ open proximal tibial physes
T/F: TWO will not affect physes as the TPLO
True
What does the Tibial Tuberosity Advancement (TTA) do
Positions the patellar lig 90 degree to slope of the tibial plateau by advancing insertion in the cranial direction to elim tibiofemoral shear force w/ wt bearing & relieves function of the CCL
TTA theoretically (reduces/increase) patellar lig tension while a TPLO (reduces/increases) patellar lig tension
Reduces; increases
What procedure has less postoperative patellar lig inflammation than a TPLO
TTA
Describe the biomechanics of TTA
- TTA places patellar lig 90 degree to slope of the tibial plateau
- By advancing insertion in cranial direction
- Eliminates tibiofemoral shear force w/ wt bearing & relieving fxn of the CCL
What is this illustrating
TTA
What is this showing
CBLO
Regardless of the tech used what should be done during sx tx of a ruptured CCL
- Meniscus inspected by arthrotomy or arthroscopy
- ID tears or other evidence of trauma
What % of pxs w/ torn CCLs have damage to the caudal body of the medial meniscus
50 to 70%
Who need thorough eval for potential complication following CCL repair
Px w/ poor outcome
What is the prognosis of long term fxn for px that have had CCL sx
Good
What is the % of dogs that improve after sx
85 to 90%
T/F: DJD can be stoped by tx
F is progresses regardless of tx
What is the long term outcome w/ CCL sx
- Decline in activity over time
- Increasing level of disability
- Adverse response to cold weather
- Stiffness after inactivity due to progress of DJD
