Knee Part 3

Question 1

Knee Plicae

Answer 1

Synovial pleats, appear as folds in the synovial membranes

Question 2

3 most commonly described plicae:

Answer 2

Inferior plica
Superior or Suprapatellar plica
Medial plica

Question 3

Irritation or trauma to the knee can cause

Answer 3

thickened plicae which can cause pain – sometimes mimics a meniscal tear

Question 4

Knee ligaments help control

Answer 4

• Excessive knee extension
• Varus and valgus stresses at the knee
• Ant. or post. displacement of the tibia
• Med. or lat. rotation of the tibia
• Combinations of the above

Question 5

MCL Proximal Attachment

Answer 5

Medial epicondyle of femur below adductor tubercle

Question 6

MCL Attachments

Answer 6

Posterior/medial joint capsule, medial meniscus, and semimembranosus tendon

Question 7

MCL Distal Attachment

Answer 7

Medial surface of the medial condyle of the tibia deep to pes anserinus

Question 8

MCL Functions

Answer 8

Provide medial stability against valgus stress and external rotation

Question 9

LCL Proximal Attachment

Answer 9

Lateral epicondyle of femur

Question 10

LCL Distal Attachment

Answer 10

Head of fibula
Blends with biceps femoris tendon

Question 11

LCL passes superficial to

Answer 11

popliteus tendon origin

Question 12

LCL Function

Answer 12

provide lateral stability against varus forces

Question 13

Cruciate ligaments have relatively poor

Answer 13

blood supply

Question 14

Cruciate ligaments
Resist extremes of all knee motions, most importantly

Answer 14

A/P shear forces

Question 15

Cruciate ligaments contain

Answer 15

mechanoreceptors that provide proprioception

Question 16

ACL Proximal Attachment

Answer 16

Medial surface of lateral femoral condyle

Question 17

ACL Distal Attachment

Answer 17

Anterior aspect of the intercondylar eminence of the tibia

Question 18

ACL Function

Answer 18

Limits the anterior displacement of the tibia relative to the femur in all positions of joint movement and limits excessive rotation

Question 19

ACL Bundles primary restraint to

Answer 19

ant. translation (shear) of tibia on femur

Question 20

PLB most taut as

Answer 20

knee extends

Question 21

ACL Bundles in knee flexion

Answer 21

PLB loosens and AMB tightens

Question 22

ACL Bundles resists _____
Restraint to _______

Answer 22

hyperextension
Varus/valgus

Question 23

ACL Bundle has limited control of

Answer 23

med. rotation of tibia via AMB

Question 24

Factors associated with noncontact ACL injury

Answer 24

Strong quadriceps activation over a moderately flexed or nearly extended knee

Marked valgus collapse

Excessive knee ER with femur IR at the hip relative to a fixed tibia

Question 25

ACL Mechanism of Injury Common

Answer 25

15-25 y/o during high-velocity sports

Question 26

Last 50 – 60 of knee extension: quads pull tibia anteriorly as tension in the ACL increases to limit

Answer 26

anterior slide of tibia

Question 27

ACL Provides 85% of passive resistance to

Answer 27

anterior slide of tibia

Question 28

Diagnosis of ACL laxity: anterior translation of tibia is greater than

Answer 28

8 mm than opposite knee (anterior drawer test)

Question 29

Rehabilitation after ACL injury/surgery: perform

Answer 29

strengthening exercises for quads in knee flexion (avoid last 50 - 60 of knee extension)

Question 30

PCL Proximal Attachment

Answer 30

Lateral side of the medial femoral condyle

Question 31

PCL Distal Attachment

Answer 31

Posterior intercondylar area of the tibia

Question 32

PCL Function

Answer 32

Limits posterior displacement of the tibia relative to the femur in all positions of joint movement

Question 33

Less tension on PCL Between

Answer 33

full extension and approximately 30º- 40º of flexion

Question 34

Tension peaks on PCL at

Answer 34

90-120 deg of flexion

Question 35

Some fibers of the PCL remain taught throughout most of

Answer 35

flexion and extension of the knee

Question 36

During squatting the PCL helps limit

Answer 36

anterior translation of the femur

Question 37

- Clinical Applications: PCL Injury - Look for posterior sag of the proximal tibia relative to the femur in the

Answer 37

supine hook lying position

Question 38

Clinical testing for PCL injury:

Answer 38

posterior drawer test

Question 39

Hamstrings are PCL ”antagonists”: PCL will limit posterior translation of the tibia when the hamstrings are

Answer 39

flexing the knee

Question 40

Popliteus tendon helps restrain ___________ if PCL is torn

Answer 40

anterior translation of femur

Question 41

Clinical Applications: PCL Mechanism of Injury

Answer 41

High-energy trauma such as MVA or contact sports (i.e., football) Falling onto a fully flexed knee with ankle PF, e.g., the proximal tibia first strikes the ground or dashboard injury Rapid descent into a deep squat