Stifle Flashcards by Corinne Perra

What are the surgical disorders of the stifle?

Cranial cruciate ligament rupture

Meniscus injury

Collateral ligament injury

Patellar luxation

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What is the anatomy of the cranial cruciate ligament?

Craniomedial band
—taut during all phases of flexion and extensions

Caudolateral band
—taut in extension but lax in flexion

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T/F: you you only have a partial rupture of the cranial cruciate ligament, it is usually the craniomedial band that is ruptured

True

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What is the function of the cranial cruciate ligament ?

Prevent internal rotation of the tibia
Prevent hyperextension of the joint
Prevent cranial tibial thrust (cranial translocation of the tibia on weight bearing

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What is cranial tibial thrust?

Natural force created by stifle because of the 145degree angle

Cranial force on the tibia when the hock is flexed and the gastrocnemius muscle contracts

Cranial tibial thrust exceeds breaking strength of the cruciate ligament = tear

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What are conditions that can predispose to cranial crutiate rupture?

Aging process — degeneration of the joint

Obesity, poor conditioning

Confirmation — straight stifle joint

Increased tibial plateau angle (TPA)

Immune mediated arthroapthies

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What is the etiology of cranial cruciate rupture

Trauma
Hyperextension and internal rotation
Jumping and landing

High TPA (tibial plateau angle) increases strain on CCL

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What is the the cause of a high tibial plateau angle?

Retared growth of the caudal portion of proximal tibial physis

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Signalment for CCL rupture?

Mature dogs

Mostly active large breeds
Obese

Can happen in any gender/breed

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History associated with acute CCL rutpure?

Following some activity

Sudden onset of non/partial -weight bearing lameness that decreases in 3-6wks

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History associated with a chronic CCL rutpure?

Prolonged weight bearing lameness

History of acute non-weight bearing lameness with gradual improvement

Difficulty rising, sits with affected limb out

Worse after exercise

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What physical exam findings are consistent with an acute CCL rupture?

Protective of joint

Need to get dog to relax quadriceps — may need sedation
Joint effusion adjacent to patellar tendon

Positive cranial drawer test or tibial compression test

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What physical exam findings are consistent with a chronic CCL rupture?

Muscle atrophy
From medial swelling :buttress
Crepitation on flexion and extension
Palpable periarticular osteophyte formation
Firm fiberous generalized swelling of joint

Limited/ “constrained” drawer sign
Palapable and audible meniscal “click”

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What clinical exam findings are consistent with a partial tear of the CCL ?

Cranial drawer in FLEXION only
Pain on extension of joint
Presence of degenerative changes lead to diagnosis

In time, show same sings as a chronic tear without joint instability

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How do you do a cranial drawer test?

Flex and extend limb to relax quads

Forefinger and thumb on bony points of each side of joint (patella and lateral fabella, tibial tuberosity and head of fibula

Hold femur in place, push tibia cranially using thumb on fibular head, while preventing internal rotation and flexion or extension of joint

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How do you do the cranial tibial thrust test AKA tibal compression test?

Place hand on cranial surface of joint, stifle slightly flexed with hock extended

Dorsiflex hock

Positive result = cranial subluxation of tibia

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How much drawer ins normal??

None!!

Puppies may have4-5mm but have abrupt stop at cranial extend

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What would you see on radiographs of a dog with acute CCL rupture? How does it appear in a chronic case?

Acute : Joint effusion
— squished fat pad
—increased radioopacity in joint

R/O other injuries

Chronic : joint effusion + osteophyte formation on patella and trochlear ridge +increased medial periarticular soft tissue

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What imaging method can you use to confirm partial CCL tears and assess degree of osteoarthritis?

Arthroscopy

Also therapeutic 
— removal of CCL remnants 
— assist in reconstruction of CCL 
—treat meniscal injury 
— treat OCD lesions

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DDX for CCL rupture?

Sprain/strains 
Patellar luxation 
Caudal cruciate ligament injury 
Primary meniscal injury 
Immune-mediated arthritis

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When is medial management indicated for CCL rupture?

Small dogs <10kgs

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How can CCL rupture be managed medically?

Confinement, rest
Weight reduction
Pain management

Physical therapy: swimming to improve muscular strength

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What are the goals of surgical management of CCL rupture ?

Establish joint stability
Lessen secondary DJD
Address any concurrent meniscal injury

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What are the surgical options for CCL rutpure?

Intracapsular reconstruction 
Extracapuslar reconstruciton 
Tibial osteotomy EVS 
— tibial plateau leveling osteotomy (TPLO) 
—tibial tuberosity advancement (TTA)

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What is done for intracapsular reconstructions of CCL ?

Replacement of CCL wit fascial graft or section of patellar tendon Placed either though bone tunnels or over the top of the femoral condyle (Inferior to other techniques)

How is extracapsular reconstruction done for CCL ?

Lateral fabellar tibial suture technique —> Heavy suture is passed around the lateral fabella and through a hole drilled in tibial tuberosity ... or ... —>Secured to bone with a “bone anchor” Suture is tied or crimped Monofilament nylon fishing line TightRope CCL —>toggle fixation mechanism, fiber tape and guide wires to allow consistent placement

T/F: Tibial plateau leveling osteotomy (TPLO) neutralizes cranial tibial thrust and drawer sign, and eliminates hamstring function by changing angle of tibial plateau

False Tibial plateau leveling osteotomy (TPLO) neutralizes cranial tibial thrust and eliminates hamstring function by changing angle of tibial plateau (active/dynamic constraint) DOES NOT eliminate drawer

A tibial plateau slope of ________ degrees allows control of tibial thrust by caudal cruciate ligament and quadriceps muscles

5-7

What is a TTA?

Tibial tuberosity advancement

T/F: Tibial tuberosity advancement (TTA) eliminates tibial thrust by positioning the patellar tendon perpendicular to the slope of the tibial plateau

True

How are patients managed postop from cranial cruciate surgery?

Compression bandage may be used for 24-36hours to control swelling Physical therapy within 48-72hours Limited exercise for 4-6weeks, until radiographic healing with TPLO or TTA Gradual return to exercise over an additional 1-2 months

Complications of surgical CCL rupture repair?

``` Infection Lack of stabilization Meniscal injury Implant complications Progressive osteoarthritis ```

What is the prognosis for CCL rupture surgeries?

Long term fxn good with all surgical methods One year post op function is better with TTA and TPLO (also a more rapid return to full function) DJD is progressive but slowed

Medical injures are caused by excessive crushing or shearing forces associated with stifle injury. Which meniscus is most affected?

Caudal body of medial meniscus Usually associated with CCL rupture which displaces the medial femoral condyle caudally in flexion —> wedging/crushing of meniscus on weight bearing and extension

What is the function of the meniscus?

Make joint surfaces congruent Distribute load transmission Shock absorption Lubrication

What is usually the presenting complaint with meniscal injuries?

Owner reports loud “pop or click” when dog walks or when joint is manipulated Sudden worsening of lameness or more lame than expected

T/F: all meniscal ruptures have pain

False Chronic - can lack pain

How are meniscal injuries diagnosed?

Arthroscopy

What is the most common type of meniscal tear?>

Caudal bucket handle tear in medial meniscus

What is the most common surgical management for meniscal tears?

Partial meniscetomy

Function of the collateral ligaments?

Provide joint stability medial and lateral Prevents varus-valgus motion

Collateral ligament injury isusualy due to?

Severe direct trauma to stifle joint Eg motor vehicle Leg caught in tree Landings

How can you diagnose a collateral ligament injur?

Varus and valgus stress test with rads to see joint laxity Joint but be extended in both tests

What is the DDX for collateral ligament injuries?

Avulsion or salter Harris fracture Condyle fracture Concurrent ligament damage (CCL)

Treatment for collateral ligament injury?

Primary reconstruction of ligaments, PO support with external fixator Prosthetic collateral support using suture or wire placed around bone anchors or bone screws

What is a common triad of ligament injuries of the stifle?

``` Cranial and caudal cruciate Medial restraints (collateral and meniscus) ```

Signalment for medial patellar luxation?

Smal and toy breeds Most common congenital deformity

What predisposes dogs to medial patellar luxation?

Medial malalignment of quadriceps —> forces alter growth of distal femoral physis and proximal tibia - lateral bowing of distal femur - lateral torsion of distal femur - medial displacement of tibial tuberosity - medial bowing of proximal tibia - abnormal development of tracheal groove - hypoplasia of medial condylar ridge

History that would be consisted with a medial patellar luxation?

Intermittent weight bearing lameness Holds leg in flexed position for a few steps “skipping gait” Grade IV have severe mechanical lameness and gait abnormalities

Grade this patellar luxation .. Patella can be manually luxated but sponteneously returns to normal position Spontaneous luxation is rare Flexion and extension of joint are normal

Grade 1

Grade this patellar luxation.. Patella luxated with lateral pressure or on flexion of stifle, remains luxated until reduced manually or when animal extends Spontaneous luxation and reduction occurs, with intermittent lameness

Grade 2

Grade this patellar luxation.. Patella is luxated most of time but can be manually reduced Reluxates spontaneously Deformities of femur and tibia

Grade 3

Grade this patellar luxation.. Stifle cannot be fully extended Patella is hypoplastic, 80-90degree of medial rotation of proximal tibial pleateau Medial displacement of quadricpts Tracheal groove is shallow Patella is luxated and cannot be manually reduced

Grade IV

DDX for patellar luxation ?

``` Legg-Perthes disease Hip luxation CCL rupture Tibial tuberosity fracture Rupture of patellar ligament ```

When is conservative management of patellar luxations indicated?

Asymptomatic older patients Grade I-II with no clinical signs — must monitor

When is surgical management of patellar luxation indicated ?

Symptomatic immature or young patients Patients with lameness and active open growth plates

Why do we want to do arthrotomy to assess the joint in patellar luxation ?

Arthrotomy to assess joint — chronic patellar luxation leads to increased stress on CCL —CCL rupture and MPL common findings

Surgical prodecures for patellar luxation?

Soft tissue reconstruction - medial fascial release - lateral imbrication Bone reconstruction - trocheoplasties (wedge/block recession OR resection) - tibial tuberosity transposition - wedge or corrective osteotomy of distal femur in severe skeletal deformity

How is a tibial tuberosity transposition done?

Tibial tuberosity is cut from proximal to distal, leaving periosteum attached distally Cranialis tibialis muscle is elevated and periosteum is removed from area lateral to tuberosity Tibial tuberosity it reattached to shaft of tibial with K wires

What is a lateral imbrication ?

When closing a lateral arthrotomy, imbricate (tighten) lateral joint capsule and retinaculum Medial release incision in joint capsule and retinaculum

What is the primary reason for recurrence of medial patellar luxation?

Only doing soft tissue reconstruction Incorporating bone reconstruction is MOST important for good prognosis

Lateral patellar luxation is usually seen in what breeds?

Large breed Appear Knock kneed Much less common than medial luxation

Stifle Flashcards

(62 cards)