Knee Complex Flashcards

1
Q

Knee

A

One of the most commonly injured areas of the body

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2
Q

What has a heavy influence on the knee?

A

The hip and ankle

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3
Q

What controls stability and mobility of the knee?

A

Boney, ligamentous, chondral, and muscular anatomy

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4
Q

3 Joint Articulations of the KNEE

A

Tibiofemoral

Patellofemoral

Proximal Tibiofibular

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5
Q

Boney Anatomy of the Knee

A

Femur
Patella
Tibia / Fibula

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6
Q

Ligamentous Anatomy of the Knee

A

ACL, PCL, LCL, MCL
MPFL
Posterolateral Corner

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7
Q

Chondral Anatomy of the Knee

A

Menisci
Chondral Cartilage

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8
Q

Muscular Anatomy:

Knee extensors
(Quad muscles)

A

Vastus Medialis
Vastus intermedius
Vastus Lateralis
Rectos Femoris

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9
Q

Muscular Anatomy:

Knee Flexors
(Hamstring muscles)

A

Semimembranosus
Semitendinosus
Biceps Femoris

Gracilis
Popliteus
Gastrocnemius

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10
Q

Muscular Anatomy:

Hip rotators

A

TFL and Glute Max into IT Band
Sartorius
Adductors

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11
Q

Tibiofemoral Joint
Structure

A

~Distal FEMUR approximating with proximal TIBIA
~Double Condyloid
~3 DOF

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12
Q

Tibiofemoral Joint
Osteokinematics

A

~Sagittal plane - flexion / extension around coronal axis
~Transverse plane - ER / IR around longitudinal axis
~Frontal plane - abduction/ adduction around A-P axis

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13
Q

Tibiofemoral Joint:
Femur

A

~Femoral condyles are medial to the head due to obliquity
~Medial condyle extends further creating a parallel surface to the ground
~Femoral condyles have a convex surface
~Intercondylar notch

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14
Q

Tibiofemoral Joint:
Tibia

A

~Relatively flat compared to femoral condyles
~Asymmetrical plateaus = medial > lateral
~Tibial plateau has a posterior slope of 7-10 degrees

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15
Q

Which osteokinematic motion does the tibial plateau angle/ posteriorslope assist with?

A

Flexion / Extension

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16
Q

Tibiofemoral Joint:
Weight bearing
Q-Angle

A

~Physiologic angulation
~Normal: 180-185 degrees
~Genu Valgum > 185 deg
~Genu Varum < 175 deg

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17
Q

Menisci Role

A

~Attached to the tibial plateau

~Greater contact area between surfaces
~Reduces stress/friction
~Enhance stability
~Shock absorption

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18
Q

Menisci Anatomy

A

~Fibrocartilaginous disc
~Semicircular / wedge shape
~Attached via roots, ligaments, capsule
~Compression 1-2x BW, 3-4x/BW
2 Menisci

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19
Q

Medial Meniscus

A

~Larger ‘C’ shape
~More ligamentous attachments, less mobile

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20
Q

Lateral Meniscus

A

~Smaller ‘O’ shape
~More mobile

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21
Q

Menisci Nutrition

A

~Blood supply - White vs Red Zones
—->More blood supply in the lateral aspects of menisci
~Innervation - anterior and posterior horns well innervated
~Central portions receive nutrients via reciprocal loading and diffusion through synovial fluid

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22
Q

Menisci Wedge

A

Allows for axial load to disperse radially “hoop stress”

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23
Q

Menisci Movement

A

~Allows for best joint congruency during knee motion
~Compressive forces increase at end ranges of motion
~Injury can occur POSTERIOR horn at end range FLEXION
~Injury can occur to ANTERIOR horn at end range EXTENSION

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24
Q

Tibiofemoral Joint:
Joint Capsule

A

~Poor boney congruency, more reliance on inert structures
~Synovial layer - meant to secrete and absorb fluid, providing nutrients and lubrication
~Strongly innervated to provide feedback -nociceptors and mechanoreceptors

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25
Q

Joint Capsule
Extension

A

Bony congruence and ligaments most taught “closed pack”

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26
Q

Joint Capsule
Flexion

A

Passive structures get more lax, allowing more translation/ rotation of tibiofemoral joint “open pack”

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27
Q

Joint Capsule
Anterior Portion

A

~Medial/lateral retinaculum
~Medial patellofemoral ligament (MPFL)

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28
Q

Joint Capsule
Medial Portion

A

Medial collateral ligament (deep and superficial)

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29
Q

Joint Capsule
Lateral Portion

A

Iliotibial (IT) Band reinforces

30
Q

Joint Capsule
Posterior Portion

A

Arcuate and posterior oblique ligament

31
Q

Anterior Cruciate Ligament
(ACL)

A

~Highly injured
~Lateral / posterior femur to Medial / anterior tibia
~Consists of 2 bundles
~Provides rotary stability with valgus/varus moments
~Intracapsular, extrasynovial

32
Q

ACL is the primary restraint against _____________of the tibia and _______________of the knee

A

Anterior translation; Excessive valgus forces/moments

33
Q

ACL Anteromedial Bundle

A

Taught in flexion

34
Q

ACL Posterolateral Bundle

A

Taught in extension

35
Q

Posterior Cruciate Ligament
(PCL)

A

~Shorter and less oblique than ACL
~Attaches from posterior tibia to medial femoral condyle
~PCL and meniscofemoral ligament form PCL complex
~Contributes to rotary and valgus/varus stability
~Intracapsular, extrasynovial

36
Q

PCL primary restricts _________________ of the tibia

A

Posterior translation

37
Q

Medial Collateral Ligament
(MCL)

A

~Divided into superficial and deep layers
~Deep layer connected to meniscus
~MCL is “less taught” as knee is flexed through ROM

38
Q

MCL primarily restrains ______________ moment at the knee and secondarily restrains __________ rotation.

A

Valgus; lateral

39
Q

Lateral Collateral Ligament
(LCL)

A

~Attaches to the lateral femoral condyle and fibular head
~Considered part of the posterior lateral corner

40
Q

LCL primarily restrains excessive _________ forces and secondarily restrains _________ rotation.

A

Varus; lateral

41
Q

Iliotibial Band (ITB)

A

~Thick fibrous band / fascia forming from TFL fibers and posterior fiber of the glute max
~Inserts onto Gerdy’s tubercle on lateral tibia
~NOT contractile, remains taught regardless of hip/knee position

42
Q

ITB Main concern

A

Fat pad between ITB insertion and tibia can take on stress/friction and cause pain

43
Q

Knee Extension

A

Normal: 0-10 degrees

Genu recurvatum >10 degreed

44
Q

Knee Flexion

A

Normal: 0-150 degrees

45
Q

Knee Accessory Motion

A

IR/ER: ~10 degrees | Screw Home Mechanism

Abduction/Adduction: Varus/Valgus

46
Q

Tibiofemoral Joint
Open Chain Arthrokinematics

A

Tibia (concave) on Femur (convex) = Same
Flexion: Posterior roll and glide
Extension: Anterior roll and glide

47
Q

Tibiofemoral Joint
Closed Chain Arthrokinematics

A

Femur (convex) on Tibia (concave) = Opposite
Flexion: Posterior roll, anterior glide
Extension: Anterior roll, posterior glide

Example: squat

48
Q

Screw Home

A

~Greater medial plateau, shorter lateral femoral condyle
~Tibial external rotation occurs at last 30 degrees, most noticeable in full or hyperextension

~Open chain: Tibial ER on Femur during extension
~Closed chain: Femoral IR on Tibia during extension

49
Q

Screw Home

A

~Unlocking the knee
~From extension to flexion
~Laterally rotated tibia must IR upon initiation of flexion

~Open chain: Tibia must ER during last 30 deg of extension
~Closed chain: Tibia must IR during last 30 deg of extension

50
Q

Factors guiding “Screw Home” rotation

A
  1. Shape of medial femoral condyle
  2. Tension in ACL
  3. Lateral pull of quadriceps
51
Q

Patellofemoral Joint:
Patella

A

~Largest sesamoid bone in the body
~Embedded in the quadriceps muscle
~Incongruent joint

52
Q

Primary Function of the Patella

A

Anatomical pulley for the quadriceps muscle

53
Q

Patellofemoral Joint:
Patellar Positioning

A

~Patella Alta = longer patellar tendon
——>less congruency, more risk of subluxation

~Patella Baja = shorter patellar tendon

54
Q

As the knee _______, there is more contact of the patellofemoral joint.

A

flexes

55
Q

Patellofemoral Joint:
Patellar tracking

A

~Slight medial movement at initiation of flexion
~Continued inferior glide once in trochlear groove

56
Q

Patellofemoral Stability

A

Frontal Plane
~Physiologic valgus at femur/tibia
~Quadriceps pulls patella slightly laterally
~Medial structures help stabilize

57
Q

In knee extension, the patella sits in superior _________________.

A

Femoral sulcus

58
Q

What helps stabilize the Patellofemoral Joint?

A

Inert Tissue Stability
~Boney congruency
~Retinaculum - ligamentous, synovial capsule
~Plica

59
Q

Q - Angle

A

Frontal Plane : physiologic valgus at femur / tibia
~Angle formed between ASIS to midpoint of patella and a line connecting the tibial tuberosity and midpoint of patella

60
Q

Normal Q-Angle between _____ and _____ degrees.

A

180; 185

61
Q

Increased Q-angle associated with

A

increased subluxation

62
Q

Tibiofemoral Joint
Open-Packed Position

A

20-25 degrees

63
Q

Tibiofemoral Joint
Closed-Packed Position

A

Full extension with lateral rotation

64
Q

How does genu valgum alter the mechanical axis of the lower extremity?

A

“Knock Knees”
~WB line is shifted onto the lateral compartment

65
Q

What effect can genu valgum have on the compressive loading of the articular cartilage in each tibiofemoral compartment?

A

~Compression forces are increased on the lateral aspect of the TFJ

66
Q

What are the patella plicae?

A

~Folds created by the failure of the synovial membrane to become fully reabsorbed
~Infrapatellar plica most common

67
Q

What implications do plicae have in knee joint dysfunction?

A

~Can become impinged with knee flexion
~May become irritated and inflamed, leading to pain, effusion, and changes in joint structure and function

68
Q

Identify and describe which muscles are capable of altering strain on the anterior cruciate ligament.

A

~Any muscle action that produces shear forces at the Tibiofemoral joint
~Quads and gastro -ant shear on tibia
~Hamstrings relieve ACL of ant shear of tibia

69
Q

3 major bursae of knee joint

A

~Suprapatellar bursa -ant. brw quads tendon and ant femur super. to patella
~Subpopliteal bursa - post. btw popliteus tendon and lat femoral condyle
~Gastrocnemius bursa - btw tendon of the med head of gastro and medial femoral condyle

70
Q

T/F All 3 major bursae are continuous with the synovial capsule of the knee

A

True; but mostly the suprapatellar

71
Q

At which point in the knee’s ROM is axial rotation greatest?

A

90 deg knee flexion