Cruciate Ligament Disease

Question 1

cranial cruciate ligament

Answer 1

runs from the caudolateral femur to the cranial medial tibia

made of 2 bands:
1. cranio-medial
2. caudolateral

Question 2

CrCL cranio-medial (CM) band

Answer 2

always tight (during extension and flexion)

Question 3

CrCL caudolateral (CL) band

Answer 3

only tight during stifle extension (loose during flexion)

Question 4

what are the 3 functions of the cranial cruciate

Answer 4

1. prevent cranial translocation of the tibia
2. prevents internal rotation of the tibia
3. prevents hyperextension of the stifle

Question 5

CrCL disease

Answer 5

chronic degenerative disease with unknown cause; leads to cranial translocation and internal rotation of the tibia

often rupture opposite CrCL within 18 months

Question 6

partial CrCL tear

Answer 6

if CM band torn: joint is unstable only in flexion

if CL band torn: joint is still stable in both flexion and extension

both cause pain on hyperextension

Question 7

complete CrCL tear

Answer 7

tearing of both the CM and CL bands

joint is unstable in flexion and extension

Question 8

signalment for CrCL disease

Answer 8

dogs
4-8 years old
breeds: rotties, labs, newfoundlands

increased risk with obesity

Question 9

diagnosis of CrCL tear

Answer 9

orthopedic exam
- drawer test
- tibia compression test
- radiographs

Question 10

drawer test

Answer 10

applying passive motion to detect cranial tibial translation

check in both flexion and extension

Question 11

tibia compression test

Answer 11

indirect drawer

mimics standing position to detect tibial translation
- keep the knee in position with one hand
- using other hand, push the tarsus upward (flex)
- if positive - the tibia will move cranially as quads contract

Question 12

CrCL tear on radiographs

Answer 12

• joint effusion
• OA signs near tibia
• periarticular thickening (medial buttress)
• cranial displacement of infrapatellar fat pad

Question 13

non-surgical CrCL treatment

Answer 13

allow scar tissue to form with rest, pain management, and weight loss

CrCL has little/no healing potential - if there are any signs of improvement it is only due to scar tissue formation in attempt to stabilize joint

Question 14

surgical CrCL treatment

Answer 14

1. prosthetic ligaments
2. osteotomies

Question 15

prosthetic ligaments

Answer 15

augments the function of the ligament
- stabilizes joint and prevents tibial thrust and cranial drawer

includes lateral suture and tight rope

Question 16

lateral suture

Answer 16

suture placed around the fabella and through a hole in the tibia

better for old, small dogs

achieves normal gait at walking only

Question 17

tight rope

Answer 17

stronger suture material but higher risk of infection

has similar outcome as TPLO even in large dogs

Question 18

osteotomies

Answer 18

alters the biomechanics of the knee by making the tibial plateau angle (TPA) perpendicular to the patellar tendon in order to eliminate cranial tibial thrust when the quads pull upwards

knee becomes stable only when weight-bearing
- eliminates cranial tibial thrust during weight bearing
- still have positive cranial drawer motion after sx

includes TPLO and TTA

Question 19

tibial plateau leveling osteotomy (TPLO)

Answer 19

flattening the tibial plateau

most effective in long term and fastest recovery time

Question 20

tibial tuberosity advancement (TTA)

Answer 20

moves the insertion of the quads (tibial tuberosity) cranially to create a perpendicular force to the existing tibial plateau

Question 21

post-op CrCL care

Answer 21

standard wound care
8-12 weeks controlled exercise
- need to allow time for bone healing and scar tissue formation
- physical rehabilitation

Question 22

meniscus

Answer 22

C-shaped cartilage that provides stability and allows for force distribution from the femur to the tibia

Question 23

how do CrCL tears predispose an animal to meniscus tear

Answer 23

CrCL tear increases pressure on one side of the meniscus over the other

Question 24

medial meniscus

Answer 24

attaches to the tibia

gets crushed during cranial tibial translocation - most likely site of meniscus tear following CrCL tear

Question 25

lateral meniscus

Answer 25

attaches to the femur

gets pulled during cranial tibial translocation

Question 26

what kind of tear usually occurs on the meniscus

Answer 26

bucket handle tear
- torn part flips back and forth when the knee is in ROM causing clicking sound and pain

Question 27

treatment for CrCL and meniscus tear

Answer 27

1. medial meniscal release
2. meniscectomy

Question 28

medial meniscal release

Answer 28

transection of the caudal meniscotibial ligament to prevent future injury

eliminates force distribution function of the meniscus

Question 29

meniscectomy

Answer 29

partial or segmental removal of the torn part of the meniscus