Knee Joint

Question 1

Which two joints sit within the knee joint capsule?

Answer 1

Femur with tibia (tibiofemoral)

femur with patella (patellofemoral)

Question 2

Which movements occur at the knee joint?

Answer 2

Flexion/extension

Rotation (during flexion)

Question 3

When is the knee joint most stable?

Answer 3

In extension (close packed position)

Question 4

What does the patellofemoral joint share the joint cavity with?

Answer 4

The knee

Question 5

Do the articular surfaces of the knee joint provide much support?

Answer 5

No

Question 6

Which 3 structures provide primary support to the knee joint?

Answer 6

Cruciate ligaments (ant & post)

Collateral ligaments (med & lat)

Menisci (med & lat)

Question 7

When is the knee joint susceptible to injury?

Answer 7

In flexion and rotation

Question 8

Which condyles of the knee joint are longer?

Answer 8

Medial condyles of both tibia and femur are longer than the lateral

Question 9

How does rotation occur at the knee joint

Answer 9

Femur rotates medially on fixed (weight bearing) tibia

Question 10

When does rotation occur in the knee joint? Around which ligament?

Answer 10

In last 15-20 degrees

Occurs about tight ACL

Question 11

When are all knee ligaments tight?

Answer 11

In full extension

Question 12

Which muscle unlocks the knee joint?

Answer 12

Popliteus

Question 13

Does popliteus have an intracapsular origin?

Answer 13

Yes

Question 14

Where is the knee joint capsule attached?

Answer 14

Around articular margins

Question 15

What are the anterior reinforcements of the knee joint?

Answer 15

Patellar tendon

Retinacular fibres

Question 16

What are the lateral reinforcements of the knee joint?

Answer 16

Popliteus, biceps femoris, iliotibial tract

Question 17

What are the medial reinforcements of the knee joint?

Answer 17

Pes anserinus’ tendons

Question 18

What are the posterior reinforcements of the knee joint?

Answer 18

Oblique popliteal ligament - from semimembranosus

Question 19

Where are the deficiencies in the knee joint?

Answer 19

Above patella for suprapatellar bursa

Posteriorly, for popliteus tendon & semimembranosus bursa

Question 20

What is pes anserinus?

Answer 20

From anterior to posterior, the tendons are:

Sartorius, gracilis, (bursa) and semitendinosus

“Say grace before tea”

Question 21

What are the bursae around the knee joint?

Answer 21

Suprapatellar bursa above patella

popliteus/semimembranosus bursa posteriorly

prepatellar, superficial infrapatellar, deep infrapatellar

Question 22

Which bursae communicate with the knee joint?

Answer 22

Suprapatellar and popliteus/semimembranosus bursa

Question 23

Which bursae of the knee joint are non-communicating?

Answer 23

Prepatellar

Superficial infrapatellar

Deep infrapatellar

Question 24

What are the cruciate ligaments of the knee joint named according to?

Answer 24

Tibial attachments

Cross within joint

Question 25

True or false: anterior and posterior cruciate ligaments are intrasynovial?

Answer 25

False Extrasynovial

Question 26

What are the functions of the anterior and posterior cruciate ligaments?

Answer 26

Primary stabilisers in A-P direction

Question 27

What happens to the ACL in going from flexion to extension?

Answer 27

Hamstrings produce posterior shear force on tibia, reducing strain on ACL and counterbalances anterior shear provided by quadriceps.

Question 28

What does the ACL do?

Answer 28

Tightens & untwists prior to extension (last 15-20 deg) Passively rotates lateral condyle in medial direction Assists internal rotation of femur & contributes to locking.

Question 29

When does ACL injury occur?

Answer 29

When rotation occurs in opposite direction (laterally) Involves extension on weight-bearing leg.

Question 30

What happens in an ACL graft?

Answer 30

ACL graft using hamstrings can take 1-3 years for graft site to repair New insertion commonly as much as 4cm prox to pes anserinus

Question 31

What does the PCL do?

Answer 31

Limits posterior displacement of tibia in knee flexion

Question 32

When is the PCL prone to injury?

Answer 32

Fall on flexed knee Bumper bar impact

Question 33

What are the 2 parts to the medial collateral ligament?

Answer 33

Long, flat superficial part Deep part blends with capsule & attaches to medial meniscus

Question 34

What does the medial collateral ligament do?

Answer 34

Resists valgus (abduction) forces & lateral rotation of tibia because of alignment (not vertical but A-P) also limits anterior displacement of tibia when ACL damaged (2nd restraint)

Question 35

What separates the lateral collateral ligament from the lateral meniscus?

Answer 35

Popliteus tendon

Question 36

Which forces does the lateral collateral ligament resist?

Answer 36

Varus (adduction) forces

Question 37

Which collateral ligament is injured most often?

Answer 37

Medial

Question 38

What are the functions of menisci?

Answer 38

Shock absorb Weight distribution Wedge-shaped, increase area of contact by ~⅓

Question 39

When do the menisci move?

Answer 39

With the femur in rotation

Question 40

Which meniscus is more commonly injured?

Answer 40

Medial

Question 41

Why is the medial meniscus more commonly injured?

Answer 41

It is longer Horns are further apart It is less mobile (due to attachment to MCL)

Question 42

Which parts of the menisci have covering in the synovial cavity?

Answer 42

Peripheral parts

Question 43

What does the meniscus contribute to?

Answer 43

Locked knee

Question 44

What does meniscus removal lead to?

Answer 44

↑ incidence OA

Question 45

What are the articular surfaces in the patello-femoral joint?

Answer 45

Patella & patellar surface of femur

Question 46

What 3 structures maintain the normal alignment of the patellofemoral joint?

Answer 46

Strong vastus medialis muscle Medial patellar retinaculum Raised lip on lateral femoral condyle (arrow)

Question 47

What pulls the patella laterally?

Answer 47

Quadriceps

Question 48

What is the mechanical problem of patellofemoral mechanics?

Answer 48

Patella pulled laterally by strong quadriceps muscles tracking of patella in femoral groove → degeneration of cartilage (chondromalacia patella) Angle (‘Q - quadriceps angle’ between tendon of quads & patellar tendon) Predisposes to subluxation/dislocation