Stifle Flashcards
Describe the attachments of the cranial cruciate ligament
medial side of the lateral femoral condyle, to the cranial intercondylar tibia
Describe the attachments of the caudal cruciate ligament
medial femoral condyle to the popliteal notch of the tibia
What is the function of the cranial cruciate ligament?
to prevent cranial tibial translation/thrust
What happens in a cranial cruciate avulsion, and how is it treated?
- small piece of bone with ligament breaks off
- repaired with lag screw or K-wire
What can cause acute traumatic rupture of the cranial cruciate ligament?
Describe the injury
- excessive limb loading or hyperextension
- painful, non-weight bearing lameness, and joint instability
- “mop end” tear of ligament
What are the predisposing factors for progressive degeneration of cranial cruciate ligament?
- increased tibial plateau angle
- obesity
- abnormal confirmation
- rottweilers, labs
- femals
- sterilized
Explain the biomechanics of cranial tibial thrust
- downward force acts on stifle
- upward force from quadriceps pulls on patella
- creates a shear at stifle
What can be found on PE of a dog with a cranial cruciate injury?
- stifle pain on extension and flexion
- crepitus, with “click” if concurrent meniscal tear
- medial buttress (fibrosis)
- quadriceps muscle atrophy
- joint effusion on med and lat aspects of patellar ligament
- dog sits with legs out to the side
Describe the components of the cranial cruciate ligament
- craniomedial band is taut in flexion and extension
- caudolateral band is taut in extension
What is the cranial drawer test?
- confirms joint instability by creating cranial tibial translation
What is meant by “puppy drawer”?
- puppies < 6 months will have some cranial tibial translation
- limited to 4-5 mm
What is the tibial compression test?
- creates stifle joint compression and results in cranial tibial thrust
- stimulates gastrocnemius tension
What can be found on radiograph of an animal with cranial cruciate disease?
infrapatellar fat pad may be caudally displaced or contain osteophytes
What is the gold standard for joint evaluation?
arthroscopy
What are the functions of the menisci?
- load distribution
- shock absorption
- joint intability
Which meniscus is most commonly affected?
medial meniscus
Why are the menisci prone to injury concurrent with a cranial cruciate injury?
- when the cruciate ruptures, the menisci acts as a joint stabilizer
- acts as a wedge to prevent further subluxation
What is the most common type of meniscal tear?
bucket handle tear
- displaced vertically
What are the treatment options for a meniscal tear?
- primary repair rarely done
- partial meniscectomy
- meniscal release
Describe the intra-articular reconstruction procedure
- utilizes fascia lata or patellar ligament
- passed through joint at lateral femoral condyle
- poor success rate
Which procedures are used to treat cranial cruciate ligament rupture/disease?
- intra-articular reconstruction
- lateral suture stabilization
- tightrope
- tibial plateau leveling osteotomy
- tibial tuberosity advancement
Describe the lateral suture stabilization technique
- place suture around lateral fabella
- pass suture through hole drilled in tibial tuberosity
- position limb at 110 degrees flexion and tighten suture until cranial drawer is eliminated
What is the prognosis for lateral suture stabilization?
- 85% improvement
- rehabilitation very important
Describe the tightrope procedure
- extracapsular technique
- counteracts cranial tibial thrust
- holes drilled through distal femur and proximal tibia
- tensioner to control desired tension
Describe the tibial plateau leveling osteotomy
- alter tibial plateau angle to eliminate the shearing force
- Rotate proximal tibial fragment so the plateau is perpendicular to the weight-bearing axis
Describe the tibial tuberosity advancement procedure
- alter patellar angle perpendicular to plateau to neutralize shear forces
Which skeletal abnormalities can induce medial patellar luxation?
- coxa vera: decreased angle of inclination
- femoral retroversion
What are the conformational abnormalities associated with medial patellar luxation?
- distal femoral varus
- genuvarum
- shallow trochlear groove
Describe a grade 1 medial patellar luxation
- no lameness
- patella can be manually luxated
- patella returns to groove after release
Describe a grade 2 medial patellar luxation
- occasional spontaneous luxation
- intermittent lameness
- once luxated, has to be manually reduced
Describe a grade 3 medial patellar luxation
- patella is continuously luxated but can be manually reduced
- more severe lameness
Describe a grade 4 medial patellar luxation
- patella fixed in luxation
- cannot manually reduce
- severe lameness
Describe a trochlear sulcoplasty
- remove hayline cartilage and subchondral bone
- fill in with fibrocartilage
Describe a trochlear chondroplasty
- creation of cartilage flap from subchondral bone
- for patients < 6 months
Describe a trochlear wedge resection
- wedge cut from peak of condyles
- subchondral bone is deepened
- wedge is replaced
Describe a tibial tuberosity transposition
- centers ligament in patellar groove
- osteotomy of tibial tuberosity
- shift tuberosity lateral and secure with K-wire and tension band
What skeletal abnormalities are associated with lateral patellar luxation?
- distal femoral valgus
- lateral condylar hypoplasia
- genuvalgum
