Knee

Question 1

The tibio-femoral joint is comprised of what two bones?

Answer 1

The tibia and the femur

Question 2

When talking about stability, just like we were dealing with at the hip we’re talking about the need to be able to disperse high loads going through the knee joint. As we move from the head down the body every more inferior joint that we go has to accommodate more body weight above it. So as we progress down the limb, we have (higher/lower) load requirements. In order to accommodate these high loads, we have to have a lot of stability right and our stability in this case is through joint congruency but then also the (active/passive) subsystem.

Answer 2

higher; passive

Question 3

Example of loads going through the knee:
Walking on a level surface is 1.3 times your body weight going through the patella femoral joint. As soon as you start to increase the (flexion/extension) angles, I.E. going up and down steps that force now increases to three times the body weight. And then deep knee bends as you bend deeper and deeper (for instance, a squat or picking something up) you’re at about eight times your body weight going through the patella femoral joint

Answer 3

flexion

Question 4

The (low/high) loads along with the large range of motion that’s necessary at the knee, it is fairly common to have things like arthritis present itself throughout the knee joint.

Answer 4

high

Question 5

DJD:
Because of trying to have high amounts of motion and (high/low) loads at the knee it lends itself to being able to have a breakdown of those cartilage surfaces.

Answer 5

high

Question 6

We have a mechanical and an anatomical axis when it comes to the knee. The (anatomical/mechanical) axis is the axis in which the line of gravity passes. We know the femur is not perfectly straight up and down, so we have this (anatomical/mechanical) axis going through the shaft of the femur.

Answer 6

mechanical; anatomical

Question 7

Because we’re not coming straight down along the mechanical axis and the anatomic axis is just off center, the medial femoral condyle has to be a little bit (smaller/larger) and run a little more (proximal/distal) in order for there to be a flat surface at the knee.

Answer 7

larger; distal

Question 8

Because the femur is a main component of both the hip joint and the knee joint, motion at the femur affects the position of the knee joint.

Answer 8

Got it

Question 9

Any kind of hip internal rotation will also twist the femur at the knee level and cause an increase in (valgus/varus) position of the knee.

Answer 9

valgus

Question 10

The MCL at the knee resists (valgus/varus) forces

Answer 10

valgus

Question 11

The LCL at the knee resists (valgus/varus) forces.

Answer 11

varus

Question 12

In extension, the MCL contributes to resisting _% of valgus force at the knee

Answer 12

57

Question 13

When the knee is flexed 25 degrees, the MCL contributes to resisting _% of valgus force

Answer 13

78

Question 14

You would not test the MCL in an (flexed/extended) position. You would want to (flex/extend) the knee (think of it as unlocking it a little bit) to test it.

Answer 14

extended; flex

Question 15

In extension, the LCL contributes to resisting _% of varus force at the knee

Answer 15

55

Question 16

When the knee is flexed 25 degrees, the LCL contributes to resisting _% of varus force

Answer 16

70

Question 17

The MCL blends with the (biceps femoris/semimembranosus) and the LCL blends with the (biceps femoris/semimembranosus).

Answer 17

semimembranosus; biceps femoris

Question 18

The LCL does not attach to the lateral meniscus. True or false?

Answer 18

True

Question 19

The (cruciate ligaments/menisci) are the sponge like material that is attached to your tibia that take up space and occupy space and increase congruency. Between the rounded femur and the relatively flat tibia we have the menisci which kind of accommodate that rounded femur.

Answer 19

menisci

Question 20

In knee flexion, both sections of the menisci deform (anteriorly/posteriorly). In knee extension, both sections of the menisci deform (anteriorly/posteriorly). This small deformation is completely normal and it is imperative when it comes to absorbing force and load.

Answer 20

posteriorly; anteriorly

Question 21

The menisci work to (increase/decrease) surface. Force is transmitted through the menisci and absorbs the impact and allows it to transfer throughout an increased surface area of the bony articulation or the joint articulation. If the menisci were not present you will see the force going through a (smaller/larger) surface area, you will have a more concentrated area of force and dispersion. So that area will become more and more vulnerable to joint injury.

Answer 21

increase; smaller

Question 22

In the 0-90 degree range of the knee, the menisci is responsible for about (50%/75%) of the compressive load distribution.

Answer 22

50%

Question 23

In a partial/total menisectomy where the meniscus is partially/totally removed there is a significant (increase/decrease) in contact stress since the meniscus can not distribute the load from the forces coming in this region.

Answer 23

increase

Question 24

During something like a squat, you get a co contraction between the ___ and the ____ (what muscle groups?). These muscles are not operating most of the time during real life situations in isolation, they are mostly a co contraction.

Answer 24

quadriceps and the hamstrings

Question 25

The ACL prevents the (forward/backward) translation of the tibia on the femur.

Answer 25

forward

Question 26

ACL tension produced by a force from combined contraction of the quadriceps and the hamstrings is a lot (more/less) than tension produced by a force from isolated contraction of the quadriceps. When you have a co contraction between the quads and the hamstring, the hamstring is pulling back on the tibia so you don’t get as much forward translation or tension on the ACL.

Answer 26

less

Question 27

When you are thinking about exercises for a knee after ACL reconstruction, you want to favour (closed/open) kinetic chain exercises in the more flexed range of the knee. So if you are doing exercises in the 45-90 degree of knee flexion, you are now producing minimal strain on the ACL. If you want to do knee flexion exercises in the 10-30 degree range, you would probably want to focus on (closed/open) chain activities.

Answer 27

open; closed

Question 28

What osteokinematic motions can occur at the knee?

Answer 28

Flexion/Extension and medial/lateral rotation

Question 29

For arthrokinematics at the knee, we have the normal roll and slide mechanisms that occur during (flexion and extension/medial rotation and lateral rotation). A spin is also possible.

Answer 29

flexion and extension

Question 30

The ability to medially and laterally rotate is affected by the position of the knee. If you are in an (flexed/extended) position, you do not have the ability to medially and laterally rotate. If your knee is sitting off of the edge of the table and flexed to 90 degrees, you do have the ability to internally and externally rotate the tibia. In extension there is max congruity and taught ligaments. So in full (flexion/extension) is the closed packed position. In 90 degrees of flexion there is (more/less) congruity of the join and the ligaments are more laxed and that allows you to have medial and lateral rotation.

Answer 30

extended; extension; less

Question 31

The medial side of the condyle extending more (proximally/distally) than the lateral side of the condyles is thought to have a major role in what is occurring during the Screw Home Mechanism. This mechanism is something that we think is coupled motion. It’s going to be flexion and extension combined with medial rotation and lateral rotation.

Answer 31

distally

Question 32

Because the lateral femoral condyle is smaller than the medial femoral condyle it’s going to complete its motion sooner than the medial side in opened chain extension of the knee. So as you’re extending and you get to that final five degrees of knee extension, the lateral side has completed it’s roll and slide. However, the medial side needs to continue. As that medial side continues there’s a slight twist of the tibia into (internal/external) rotation. And so that role and slide in the same direction, with the excess motion needed on the medial side causes an external rotation to occur at the tibia. That is called a screw home mechanism and that screw home rotation once it twists into place is significantly (mobilizing/stabilizing) the knee, it is locking that knee into position. So when you FLEX it now has to immediately rotate the tibia in order to unlock the knee and then provide the posterior role and slide of the tibia. Some of the ligamentous tension that’s also playing a role in this, is the tension in the acl. The ACL is going to be taught in that position, and so the maximally stabilized position is full extension. This is all open chain.

Answer 32

external; stabilizing

Question 33

We live our life mostly in the (open/closed) chain position. In closed kinetic chain rotations, the femur is going to rotate (medially/laterally) on the tibia as you get into full extension. So if I am in my chair and I go to stand up to my full height. As I get to full extension my tibia is stabilized on the ground so it doesn’t have the ability to twist. It’s my femur that is internally rotating in order to lock me into full extension. So now the tibia is in relative (internal/external) rotation. So as I start to bend my knee and sit down into the chair the femur will now externally rotate on the tibia to unlock the knee as I sit back down.

Answer 33

closed; medially; external

Question 34

Genu valgum is knocked knees and will cause the knees to appear as if they are (touching/apart) while the ankles remain apart

Answer 34

touching

Question 35

Genu valgum has an association with coxa (valga/vara).

Answer 35

valga

Question 36

In genu valgum there will be increased compression forces (medially/laterally) in the lateral joint space and the (medial/lateral) soft tissue structures will be under tension.

Answer 36

laterally; medial

Question 37

Genu valgum would cause the person to have an increased tendency towards foot (supination/pronation) (flat foot) because now the LOG is pushing them into that position.

Answer 37

pronation

Question 38

Genu varum is bow leggedness and will cause the knees to appear as if they are (touching/apart).

Answer 38

apart

Question 39

Genu varum has an association with coxa (valga/vara)

Answer 39

vara

Question 40

In genu varum, there are going to be compresses forces (medially/laterally) and have tensile forces (medially/laterally) and this could lead to more arthritis on the (medial/lateral) side.

Answer 40

medially; laterally; medial

Question 41

In genu recurvatum the individual will be in hyper (flexion/extension) of the knee with their leg behind them. This can lead to an overstretched capsule (anteriorly/posteriorly). Part of the reason why is because the external moment arm is much (smaller/bigger) in this position because the knee is further away from the LOG.

Answer 41

extension; posteriorly; bigger

Question 42

Genu recurvatum is associated with weak (quadriceps/hamstrings) that allow the hyper extension of the knee to occur.

Answer 42

quadriceps

Question 43

Genu recurvatum is associated with a stiffed ankle in (dorsi/plantar) flexion. If the ankle is stiff and doesn’t allow proper dorsi flexion to occur, the compensation is for the knee joint to buckle backwards and cause hyper extension.

Answer 43

plantar