Knee Joint

Question 1

Femoral tibial joint:

1. What kind of joint is it?
2. How many degrees of freedom?
3. Accessory movement?

Answer 1

1. Complex (has a meniscus), modified hinge (function wise), dual condylar (anatomy wise)
2. One DF (flexion extension in Transverse plane)
3. 2nd DF: rotation, long axis with knee flexed
   Angulation: abduction/adduction comes from an external force only, does not happen volitionally.

Question 2

Femoral patella joint:

1. What kind of joint?

Answer 2

1. Sellar joint, modified plane joint

Question 3

What is the resting position of the knee?

Answer 3

25-40 degrees of flexion

Question 4

What is the closed packed position of the knee?

Answer 4

Maximal extension with maximal external rotation of the leg (screw home mechanism)

Question 5

What is the capsular pattern of the knee?

Answer 5

More limitation of flexion (90) than extension (5). Seldom LOM in rotation unless gross restriction.

Question 6

Extension of the knee =

Answer 6

stability (mechanically designed for stability in extension)

Question 7

Flexion of the knee =

Answer 7

flexibility. there is a normal inherent degree of valgus built into the knee, more in women because there pelvis is wider.

Question 8

Femoral condyles in flexion and extension

Answer 8

The femoral condyles are pully shaped bi-convex. they are longer in A/P than M/L. medial condyle juts out more and is narrower. the lateral femoral condyle is more directly in line with the shaft than the medial femoral condyle. weight bearing stresses in knee equally disrtributed between medial and lateral condyles in bilateral stance.

Question 9

Tibial condyles in flexion and extension

Answer 9

the tibial condyles are reciprocally curved to femur with blunt eminience running A/P, intercondylar tubercles. the medical condyle is biconcave and the lateral condyle is concave in the fronal plane and convex in the sagittal plane. articular surface of medial condyle is 50% larger and articular cartilage is 3x thicker. the cartilage is signficantly thicker due to weight bearing.

Question 10

Axial rotation

Answer 10

modififed intercondylar tubercles of the tibia act as a pivot. tibia lodges in the intercondylar notch and rotates.

Question 11

Describe kinematics of closed chain femur and tibia

Answer 11

tibia is on the ground. the femur rotates on the tibia. we do not treat closed chain for manual therapy

Question 12

Describe kinematics of open chain femur and tibia

Answer 12

tibia on femur = for manual therapy

Question 13

Describe arthrokinematics from full extension to flexion.

Answer 13

femoral condyles roll posteriorly and glide anteriorly. ACL involved.

Question 14

Describe arthrokinematics from flexion to extension

Answer 14

femoral condyles roll anteriorly and glide posteriorly. PCL involved.

Question 15

arthrokinematics of rotation

Answer 15

lateral rotation of tibia on femur, lateral femoral condyle moves forward over the lateral tibial condyle, medial femoral condyle moves backwards.
-during neutral postion for axial rotation with knee flexed, posterior femoral condyles in contact with mid part of tibial condyles