knee part 1

Question 1

in the sagittal plane what is the tibialfemoral biomechanic morphology?

Answer 1

9º posterior tibial slope
femoral condyle decreasing radius of curvature

Question 2

what functional requirements of flexion at the TF joint is needed for several tasks?

Answer 2

level surface gait: 60-68º
ascending stairs: 80º
descending stairs: 90º
sit-stand-sit transfers: 90º
tying a shoe: 106º
full squat to floor: 150-160º

Question 3

what is the osteokinematic values for flexion at the TF joint in sagittal plane?

Answer 3

130-140º with hip flexion or 120º with hip extension

Question 4

what is the osteokinematic values for extension at the TF joint in sagittal plane?

Answer 4

5-10º hyperextension

Question 5

are the femoral condyles convex or concave?

Answer 5

convex

Question 6

is the tibial plateau convex or concave?

Answer 6

concave

Question 7

at the TF joint in OKC extension in sagittal plane what arthrokinematic motion is occurring?

Answer 7

concave tibial plateau moving on convex femoral condyles so tibial roll and slide occur in same direction (anterior)

Question 8

during OKC extension at the Tf joint where do both the menisci translate and why?

Answer 8

anterior following the tibia because they are attached to the tibia and coronary ligaments

Question 9

at the TF joint in OKC flexion in sagittal plane what arthrokinematic motion is occurring?

Answer 9

concave tibial plateau moving on convex femoral condyles so tibial roll and slide occur in the same direction (posterior)

Question 10

the semimembranosis has an attachment where?

Answer 10

on the medial meniscus

Question 11

the popliteus has an attachment where?

Answer 11

on the lateral meniscus

Question 12

what are the functions of the menisci?

Answer 12

increase tibial plateaus radius of curvature
reduces TF friction
attenuates TF compression loads

Question 13

at the TF joint in CKC flexion in sagittal plane what arthrokinematic motion is occurring?

Answer 13

convex moving on concave, posterior femoral roll followed by anterior femoral slide

Question 14

by 15º of flexion in CKC what is occurring?

Answer 14

the medial compartment posterior roll begins to be accompanied by a small amount of anterior slide

Question 15

why is knee flexion in CKC not initaited evenly upon compartments?

Answer 15

because there is greater SA on medial condyle for glide/slide articulation with medial tibial plateau than that of lateral femoral condyle and lateral tibial plateau. (essentially theres more work to do on medial side because more area to cover so has to start sooner)

Question 16

what happens if only the medial compartment is sliding anterior?

Answer 16

creates external rotation of the femur which equals internal rotation of the knee

Question 17

by 25º of flexion in CKC what is occurring?

Answer 17

lateral compartment roll begins to be accompanied by a small amount of anterior slide

Question 18

what makes up the medial compartment?

Answer 18

medial femoral condyle and medial tibial plateau

Question 19

what makes up the lateral compartment?

Answer 19

lateral femoral condyle and lateral tibial plateau

Question 20

by mid ROM of flexion in CKC what is occurring?

Answer 20

approximately equal magnitude of posterior femoral roll and anterior femoral slide in both compartments

Question 21

by late ROM of flexion in CKC what is occuring?

Answer 21

greater magnitude of anterior femoral slide than posterior femoral roll in both compartments

Question 22

by end ROM of flexion in CKC what is occurring?

Answer 22

essentially all anterior femoral slide in both compartments

Question 23

when is the angle of inclination greatest for the ACL?

Answer 23

at full extension

Question 24

what is the rule for inert tissue (ligaments) in regards to angle of inclination?

Answer 24

when the angle of inclination is greatest for ligaments it puts the structure in a compromised position to do its job. more at risk for damage (tear)

Question 25

what is the role of the ACL in closed chain?

Answer 25

to prevent posterior displacement of femur on fixed tibia

Question 26

what is the roles of the ACL in open chain?

Answer 26

prevent anterior displacement of tibia on fixed femur

Question 27

when does the ACL work best?

Answer 27

in flexion

Question 28

what impact does hyperextension have on the ACL?

Answer 28

end ROM extension brings the midsubstance of ACL in contact with the femoral intercondylar shelf (notch of Grant). this contact point acts as a fulcrum to tension load the ACL

Question 29

where does the ACL run?

Answer 29

antero-medial to postero-lateral

Question 30

where does the ACL insert?

Answer 30

medial aspect of lateral femoral condyle

Question 31

the anteromedial band of the ACL is taut when?

Answer 31

in greater degrees of flexion

Question 32

the posterolateral band of the ACL is taut when?

Answer 32

in greater degrees of extension

Question 33

the ACL has two bands what does this mean?

Answer 33

that some portion of the ACL is taut in all varying degrees of TF osteokinematic movement

Question 34

the greatest excursion of tibia anteriorly at approx 30º which means what for the ACL?

Answer 34

neither bands are taut so this is where we do the lockmans test for ACL integrity

Question 35

when is the angle of inclination greatest for the PCL?

Answer 35

at full flexion

Question 36

when does the PCL work best?

Answer 36

in extension

Question 37

where does the PCL project?

Answer 37

posteromedial to anterolateral

Question 38

are there 2 bands of the PCL?

Answer 38

yes but they function the same so discussed together

Question 39

where does the PCL insert?

Answer 39

medial aspect of lateral femoral condyle