Lecture 7: Cranial Cruciate Ligament Injury/Dx I (Exam 2) Flashcards
What are some conditions of the stifle
- Arthritis
- Luxating patella
- Cruciate meniscal syndrome
- Inflammatory joint dx
- Neoplasia
- Injury
What is the most common canine orthopedic condition
Cranial cruciate lig injuries
What is a major cause of DJD in the canine stifle
Cruciate instability
What are some general considerations about cruciate ligs
- More complex in dogs
- Dogs sustain diff degrees of rupture (partial or complete)
- invariable causes arthritis (OA)
What is the most common cause in humans
Trauma
Describe “traumatic” rupture in dogs
- Rare
- Hyperextension
- Excessive internal rotation
- Applied load exceeds strength
What is cranial cruciate ligament disease in dogs (CCLD)
- A slow degenerative process
- Occurs over a few months to years
- Not the result of sudden trauma to a healthy lig
What factors influence CCLD
- Aging of the ligament
- Obesity
- Poor physical condition
- Conformation & breed
What are the two impt features of canine CCLD
- > 50% of dogs w/ cruciate lig probs in one knee dev similar probs in the other knee
- Partial tearing of CCL common & typically progresses to full tear
Describe the incidence & prevalence of CCLD
- Affects dogs of all sizes & ages
- Uncommon in cats
- Certain breed have higher incidence (some breeds less often affected)
- Female & neutered dogs & greater risk
List breed w/ higher incidence of CCLD
- Rottweiler
- Newfoundland
- Staffodshire terrier
- Mastiff
- Akita
- Saint bernard
- Chesapeake bay retriever
- Lab
- Greyhounds
- Dachshund
- Basset hound
- Old english sheepdog
Label the following
List the ligamentous support of the stifle
- Medial & lateral collateral ligs (limit medial & lateral movement of the tibia)
- Cranial cruciate lig
- Caudal cruciate lig
What are the functions of CCL
- Restrains cranial translation of the tibia on the femur
- Restrains hyperextension of the stifle joint
- Limits internal rotation of the tibia on the femur
- Limits varus & valgus motion in flexed joint
- Restrains caudal translation of tibia on femur
What happens to the cruciate ligs during flexion
- They twist on each other
- Limit excessive internal rotation of the tibia on the femur
Label the key structures in cruciate dx
What does CCL prevent
- Cranial translation of the tibia
- larger tibial plateau angle leads to greater cranial force on the tibia @ wt bearing
What are the components of the CCL
- Large caudolateral band
- Small craniomedial band
Describe a partial rupture of the CCL
- Caudolateral band is taut in extension & laxity in flexion
- Craniomedial band is taut in all phases of flexion & extension
- Involvement of the caudaolateral band alone produces no draw sign
What happens if there is a partial rupture of the craniomedial band
- Produces small amount of drawer movement in flexion
- No drawer observed in extension
How are CCL partial ruptures Dxed
- MRI
- Surgical exploration (arthrotomy & arthroscopy)
What results in stifle instability w/ CCL deficiency
- Joint capsule inflammation
- Synovial membrane inflammation
- Degeneration of the articular cartilage
- Production of osteophytes
- Meniscal damage
What is the end result of CCL Deficiency
Progressive DJD, loss of muscle mass, decreased limb use, & decreased performance
What are the common complications of CCLD
- Long term impairment due to OA
- Tearing of meniscus
List clinical sx of CCLD
- Will not sit “square” (sits w/ leg or legs out to the side)
- Popping noise (“meniscal click”)
- Medial buttress
- Non wt bearing lame when partially damaged lig ruptures completely or the meniscus is torn
What is medial buttress
- Palpable thickening of the medial aspect of stifle
- May be grossly & radiographically visible
What are some differential dxes for CCLD
- Hip dysplasia
- Lig sprains or muscle strains
- Luxating patella
- Neuro dx
- Bone/soft tissue cancer
- Fractures
- Joint lux
- Tendon rupture
- Panosteitis
- OCd
Describe tearing of the meniscus
- Medial meniscus freq damaged
- During initial injury or later
- Meniscal damage in dogs is too small to repair & excise damaged parts of meniscus (partial meniscectomy)
- Meniscal tears are very painful if not treated w/ excision they will not regain optimal fxn
T/F: the results are more reliable in painful px w/ sedation
True
Describe the cranial drawer test
- Flexion
- Extension
- Neg drawer doesn’t r/o CCL tear (periarticular fibrosis &/or meniscal entrapment)
- Index finger over the patella
- Index fingertip on tibial tubercle
- Upper thumb on the fabella
- bottom index finger on tibial tubercle
- Bottom thumb on fibular head
What are radiographs used to for
- Assess joint effusion
- Assess degree arthritis
- Aid surgical planning
- Rule out concurrent dx
What do radiographs not do
Do not show the status (intact or damaged) of the CCL or meniscus
What can be looked for to in radiographs to dx CCLD
- Loss of fat pad definition & distention of the caudal joint capsule
- Osteophyte formation along the trochlear ridge & subchondral bone sclerosis of tibial plateau
