Ligament Injury Flashcards

1
Q

What are the 3 articulations of the stifle joint?

A
  1. femorotibial - main, primary weight bearing
  2. femoropatellar - improves efficiency of extension by increasing the movement orm of the quadriceps
  3. tibiofibular - secondary support
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2
Q

What are the 4 sesamoid bones of the stifle?

A
  1. patella - blunt proximally, pointed distally (apex)
  2. lateral fabella - larger, spherical
  3. medial fabella - smaller, angular
  4. popliteal - in the popliteal tendon of the lateral condyle of the tibia
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3
Q

What is the purpose of sesamoid bones?

A

relieve tension within muscles and tendons, allowing for increased weight bearing and tolerance by redistributing forces throughout a muscle or tendon —> protection from strain and injury

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4
Q

Femorotibial joint:

A
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5
Q

Where do the cranial and caudal cruciate ligaments originate and insert?

A

CRANIAL = originates from the caudomedial aspect of the lateral femoral condyle, inserts on the medial tibial plateau

CAUDAL = originates from the craniomedial aspect of the medial femoral condyle, inserts on the posterior tibial plateau

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6
Q

Menisci:

A

medial most commonly tears

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7
Q

What is the function of the cranial cruciate ligament? In what 3 ways does it do that?

A

stability of the stifle joint

  1. limits cranial translation of the tibia
  2. limits internal rotation of the tibia
  3. limits hyperextension of the stifle
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8
Q

What are the stifle menisci made of? What is their purpose? What is their blood supply like?

A

C-shaped fibrocartilage primarily made up of Type 1 collagen in a matrix

resists hoop stress

poor —> thick periphery is vascularized by plexi in the joint capsule

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9
Q

What is the purpose of a meniscal release? How. isit performed?

A

treats impingement by allowing the caudal horn of the meniscus to move more freely with movement of the joint in the presence of cranial tibial thrust

mid-body meniscal transection +/- transection of the caudal tibial ligament

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10
Q

Are complete meniscectomies performed?

A

NO —> causes the development of advances arthritis because there is no longer any cushion

  • it used to be thought that the menisci do not do much
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11
Q

What is the most common etiology of cranial cruciate ligament tears in dogs?

A

degenerative

(trauma in humans)

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12
Q

What are the 5 major causes of the degeneration that leads to cruciate ligament tears?

A
  1. conformational abnormalities - proximal tibia, straight legs
  2. hormonal - early castration
  3. autoimmune
  4. age
  5. body weight

(idiopathic possible)

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13
Q

How is cranial cruciate ligament tears diagnosed?

A
  • ORTHOPEDIC EXAM - gait analysis, compensatory thickening, cranial drawer, tibial compression
  • RADIOGRAPHS - can’t see ligaments, secondary changes
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14
Q

What cats are likely to tear their cranial cruciate ligaments?

A

old, obese

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15
Q

How is the gait changes by cranial cruciate tears? What is the sit test?

A

shifting, off-loading

it hurts to flex legs, so dogs with a torn CrCL will keep their legs extended

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16
Q

What are 5 signs of CrCL tear on palpation/manipulation of the joint?

A
  1. pain during stifle extension
  2. joint effusion
  3. muscular atrophy
  4. medial buttress
  5. thickening of the medial joint capsule
17
Q

What is palpated for in possible CrCL tear patients when recumbent?

A
  • joint effusion
  • ROM
  • crepitus
  • cranial drawer test
  • tibial compression test
18
Q

How is the cranial drawer test performed?

A
  • place thumb and finger of one hand on the fabella of the femur (+ pointer finger on patella)
  • place thumb and finger of other hand on the tibial crest and fibular head
  • while holding the femur in place, apply a firm cranially directed force to the tibia

POSITIVE = tibial will be able to slide forward in flexion +/- extension

19
Q

How is a tibial compression test performed?

A
  • place index finger on patella, and other fingers on femoral condyles
  • push the hock proximally to flex it

POSITIVE = gastrocnemius pulls femur caudally and tibia is able to move up

20
Q

What can radiographs show in patients with CrCL tears?

A
  • joint effusion - fat pad sign
  • osteophytes
  • medial buttress
  • sunchondral sclerosis
21
Q

What are some differential diagnoses for CrCL tears?

A
  • osteochondrosis dissecans
  • patellar luxation
  • caudal cruciate rupture
  • meniscal damage (typically seen WITH CrCL tear, best diagnosed by arthroscopy)
  • septic arthritis
22
Q

Is conservative treatment typically recommended for CrCL repair?

A

no —> uncomfortable, even for smaller dogs/cats, leads to OA and meniscal damage

  • confinement 4-8 weeks
23
Q

What is the point of extracapsular techniques when repairing CrCL? How is this performed?

A

tightens joints by grabbing bone/ligaments and anchoring them to the tibial tuberosity

lateral retinacular stabilization

  • synthetic monofilament around fabella/bone anchor
  • tunnel in tibial proximal muscle
  • recommended in cats/small dogs
24
Q

What is the point of Tightrope CrCL repair?

A

extracapsular - drills into bone and replicates ligament

25
Q

What is the point of fibula head transposition for CrCL repair?

A

extracapsular - pull fibula forward so that the LCL can replicate the CrCL

  • recommended for large dogs, durable
26
Q

What is the most common intracapsular technique used to repair CrCL tears?

A

over the top - strip of fascia lata is cut and passed through a tunnel where the cruciate was, then through the condyles, and attached through the lateral surface of the condyle

27
Q

What are the 2 most common dynamic techniques used to repair CrCLs? What are 2 pros? What are complications related to?

A
  1. tibial plateau leveling osteotomy (TPLO)*
  2. tibial tuberosity advancement (TTA)
  • offers dynamic stability - cranial drawer will be present, but the stifle is stable while weight-bearing
  • no ROM restrictions

osteotomy-related

28
Q

What is the purpose of performing a TPLO?

A

adjusts the slope of the tibia so that the femur slides cranially instead of caudally

29
Q

What is the purpose of performing a TTA? How does it compare to a TPLO?

A

cut the tibial crest and place a plate and spacer to advance it - makes crest perpendicular to the patellar tendon and prevent the tibia from moving forwards

not performed as commonly —> parts are flimsy and avulsions are common

30
Q

How do CrCL tear repairs typically progress?

A

tear typically becomes bilateral after less than 2 years

(most common cause of lameness in the dog)