61 Stifle

Question 1

What is the tibial attachment site for the cranial cruciate ligament and the cranial meniscal ligaments

Answer 1

Cranial intercondyloid area

Question 2

What is the attachment site for the medial caudal meniscal ligaments

Answer 2

Caudal intercondyloid area

Question 3

What is the tibial attachment site for the caudal cruciate ligament

Answer 3

The lateral edge of the popliteal notch

Question 4

What are the structures attaching to the cranial intercondyloid area

Answer 4

Cranial meniscotibial ligament of the medial and lateral menisci and the cranial cruciate ligament

Question 5

What is the caudal attachment of the meniscotibial ligament of the lateral meniscus

Answer 5

Popliteal notch

Question 6

What is the trajectory of the meniscofemoral ligament

Answer 6

Caudal axial border of the lateral meniscus, extends dorsally within the intercondylar fossa (medial femoral condyle)

Question 7

Describe the trajectory of the cranial cruciate ligament

Answer 7

It attaches to the caudomedial aspect of the lateral femoral condyle and the caudolateral part of the intercondyloid fossa of the femur and runs diagonally in a cranial, medial, and distal direction across the intercondyloid fossa to attach to the cranial intercondyloid area of the tibia

Question 8

Describe the trajectory of the caudal cruciate ligament

Answer 8

It attaches to the lateral surface of the medial femoral condyle and runs caudodistally to attach to the medial edge of the popliteal notch of the tibia, medial to the caudal meniscotibial ligament of the lateral meniscus.

Question 9

Which collateral is fused with the joint capsule and the meniscus

Answer 9

The medial collateral

Question 10

Which collateral is attached only loosely to the joint capsule and is separated from the meniscus by the tendon of origin of the popliteus muscle

Answer 10

The lateral collateral

Question 11

By which structure does the medial meniscus attach strongly to the joint capsule and medial collateral ligament

Answer 11

The coronary ligament

Question 12

Describe the composition of menisci and the orientation of its fibers

Answer 12

Fibers of type I collagen, mixed with a matrix of glycoprotein and proteoglycans. Fibers are arranged in layers - superficial layer is randomly oriented (similar to cartilage) to provide low-friction motion. The deeper layers are oriented circumferentially (outermost) to resist tension and radially (innermost) to resist compression

Question 13

Describe the blood supply to the menisci

Answer 13

It originates from a small reflection of the vascular layer of the synovium. These blood vessels supply the peripheral 15-25% of the menisci. The rest of the meniscus is relatively avascular

Question 14

Joint loading that causes increased strain in the cranial cruciate ligament results in simultaneous contraction of which muscle group and the relaxation of wich muscle group

Answer 14

Contraction - the caudal thigh muscles. Relaxation - the quadriceps femoris muscle

Question 15

What does a caudal meniscotibial ligament release causes on the stress distribution of the meniscus

Answer 15

A 140% increase in peak contact pressure and a 50% decrease in contact area

Question 16

Describe the impact of large meniscectomy vs partial, conservative meniscectomy

Answer 16

Cadaveric studies show that there is a direct correlation between the size of the meniscectomy and the progression of degenrative changes in the joint in the future

Question 17

Describe in your word the critical role of the menisci in stifle mechanics

Answer 17

Its wedge shape is a stabilizer (primary in CCL deficient stifle) for cranial tibial translation, its fiber orientation are critical for hoop stress distribution during weight-bearing as well as low-friction motion of the joint and is a major contributor to weight-bearing

Question 18

Describe the microscopic changes seen in CCL disease

Answer 18

Loss and metaplasia of the ligamentocytes and failure to maintain collagen fibers

Question 19

Describe the breed variation in the material property of the CCL

Answer 19

Rottweiler CCL is more vulnerable - has been shown to require half the load per unit of BW compared to the racing Greyhound

Question 20

What is the reported incidence of contralateral CCL rupture

Answer 20

22-54% of dogs will develop bilateral disease

Question 21

What is the effect of radiographic stifle effusion on the contralateral joint for the progression of bilateral disease

Answer 21

OR of 13.4 for development of a contralateral CCL rupture by 1 year after diagnosis

Question 22

What is the reported incidence of medial meniscal injury with concomitant CCL tears

Answer 22

30-80%, with the largest study on 1000 patients reporting 33.2%

Question 23

Describe the difference between postliminary and latent meniscal tears

Answer 23

Posliminary - meniscal tear that develops after the initial surgical procedure (from probable residual stifle instability)
Latent - meniscal tear that was missed during the initial surgical procedure (were present at that time)

Question 24

How does a meniscal tear propagate

Answer 24

The fissure typically starts within the proteglycan (matrix) that is weaker in both compression and tension than the collagen fibers and will continue to propagate within the weaker tissue rather than across the stronger fibers

Question 25

Describe the usefulness of MRI in the diagnosis of meniscal injury

Answer 25

Low-field MRI cannot be recommended at this time because of lack of sensitivity (0.65). However, high-field MRI has yielded good results (100% sensitivity and 94% specificity), but was only assessed on a few cases only (12)

Question 26

How important is probind during arthrotomy or arthroscopy to diagnose medial meniscal tear

Answer 26

An accurate diagnosis obtained by arthrotomy or arthroscopy was 2.1 to 2.6 or 8.0 times more likely, respectively, when probing was performed compared with observation alone