Knee Biomechanics Flashcards

1
Q

What type of joint is the tibiofemoral joint?

A

Double condyloid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The tibiofemoral joint prevents motion in what plane?

A

Frontal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The tibiofemoral joint has how many degrees of freedom?

A

2 degrees of freedom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

(T/F) Is the medial tibial plateau larger than the lateral?

A

YES: 50% larger (oval and long)
Articular cartilage 3x thicker than
lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The Medial & lateral tibial plateau slope in which direction?

A

Slope posteroinferiorly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the main functions of the menisci?

A
  • Increase stability by deepening
    tibial plateau
  • Decreases friction by 20%
  • Increases contact area by 70%
  • Enhances proprioception via
    mechanoreceptors
  • Attenuates forces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

The Medial Meniscus is what shape?

A

C-Shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

The Lateral Meniscus is what shape?

A

O-Shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where is the medial meniscus thickest?

A

Posteriorly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where is the lateral meniscus thickest?

A

Uniform thickness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What major structure is firmly attached to the medial meniscus?

A

MCL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Menisci transmit what percent of
imposed load at knee?

A

50-60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Shock absorption capability
is reduced by what percent with complete menisectomy?

A

20%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The menisci are initially well vascularized but recede to the periphery by what age?

A

11 years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The MCL prevents which motion?

A

Abduction (Valgus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

(T/F) Adduction or abduction is determined by the movement of the distal extremity (tibia)

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The LCL prevents which motion?

A

Adduction (varus stress)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The MCL assists in restraining which tibial motion?

A

Anterior tibial translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When are ALL the MCL fibers most taut?

A

Extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The MCL anterior fibers are taut in which motion?

A

Mid-range knee flexion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

The MCL posterior fibers are on slack in which motion?

A

Mid-range knee flexion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

(T/F) The LCL has an attachment to the joint capsule

A

FALSE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When are the LCL fibers most taut?

A

Extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The LCL helps restrict what motion other than varus?

A

IR/ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How many bundles are there in a typical ACL?

A

3

26
Q

What is the origin and insertion of the ACL?

A

Anterior aspect of tibial to posterior aspect of LFC

27
Q

Average ACL length and width?

A

33mm Length / 11mm width

28
Q

What motion does the ACL restrain?

A

Anterior tibial translation

29
Q

Which muscle group may help restrain anterior tibial translation?

A

Hamstrings

30
Q

Primary function of the PCL?

A

Prevents posterior translation of tibia on femur

31
Q

(T/F) The PCL is frequently injured

A

FALSE

32
Q

Which ligament prevents anterior translation of the FEMUR?

A

PCL

33
Q

Which ligament prevents posterior translation of the FEMUR?

A

ACL

34
Q

Which part of the menisci has the greatest healing potential?

A

Periphery (Red-Red Zone)

35
Q

What degree of an angle would be considered Genu Valgum?

A

<165°

36
Q

What degree of an angle would be considered Genu Varum?

A

> 180°

37
Q

Genu valgum can lead to increased pressure on which compartment of the knee?

A

increased lateral
compressive forces

38
Q

Genu Varum can lead to increased pressure on which compartment of the knee?

A

increase medial
compressive forces

39
Q

Average Q-Angle for males?

A

10-14°

40
Q

Average Q-Angle for females?

A

15-17°

41
Q

Genu recurvatum is characterized by excessive…?

A

extension

42
Q

Decreased CKC dorsiflexion would lead to?

A

Decreased knee flexion

43
Q

Decreased CKC plantar flexion would lead to?

A

Decreased Knee extension

44
Q

What is the minimum amount of knee flexion required to ambulate?

A

60° - 70°

45
Q

Describe the screw home mechanism during open chain extension and flexion

A

Extension: Tibial ER
Flexion: Tibial IR

46
Q

Describe the screw home mechanism during closed chain extension and flexion

A

Extension: Femur ER
Flexion: Femur IR

47
Q

Roll/Glide mechanics during open chain extension?

A

Concave on FIXED convex
Tibia rolls and glides anteriorly

48
Q

Roll/Glide mechanics during open chain flexion?

A

Concave on FIXED convex
Tibia rolls and glides posteriorly

49
Q

Roll/Glide mechanics during closed chain extension?

A

Convex on FIXED concave
Femur rolls anterior / glides posterior

50
Q

Roll/Glide mechanics during closed chain flexion?

A

Convex on FIXED concave
Femur rolls posterior / glides anterior

51
Q

The posterior surface of the patella is covered by which type of cartilage?

A

Posterior surface is covered with thick hyaline cartilage

52
Q

The medial facet of the patellofemoral Joint is positioned?

A

Flat to slightly convex

53
Q

The lateral facet of the patellofemoral Joint is positioned?

A

longer than medial

54
Q

The “odd” facet of the patellofemoral joint is positioned?

A

medial angle

55
Q

The 1st consistent patellofemoral contact is between?

A

10° - 20° flexion

56
Q

By 90° all aspects of facets have made contact with exception of?

A

Odd facet

57
Q

The greatest PF compression force is at what degree of flexion?

A

90°

58
Q

What are the Transverse stabilizers leading to Patellofemoral Joint Stability?

A

Med/lat retinaculum
VMO/VL
MPFL

59
Q

What are the Longitudinal stabilizers leading to Patellofemoral Joint Stability?

A

Quad tendon
Patellar tendon

60
Q

The MCL and LCL, to a lesser extent, resists?

A

External rotation

61
Q

3 parts of the unhappy triad?

A

ACL, MCL, Medial meniscus