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athletic injuries 2036 > Lecture 15: Medial support complex > Flashcards

Lecture 15: Medial support complex Flashcards

1
Q

what are the 3 layers of tissue in the medial support complex?

A

1: superficial
2: middle
3: deep

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2
Q

superficial layer of the medial support complex

A
  • sartorius and fascia
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3
Q

middle layer of the medial support complex

A

contains superficial MCL and semimembranosus (which is part of the hamstrings)

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4
Q

what is apart of the deep layer of the medial support complex?

A

contains deep fibers of MCL and capsule

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5
Q

stability of the medial support complex

A
  • MCL primary stabilizer 25-30 degrees of flexion
  • muscles help in full extension
    • medial hamstrings (Sartorius, semimembranosus + semintondosus )
    • medial head of gastrocs
    • quad muscles (vastus med)
  • bony structure is tertiary support
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6
Q

Medial collateral ligament (MCL)

A
  • a capsular ligament
  • has superficial and deep components
    • deep portions connect directly to the medial meniscus
    • superficial portions run from medial femoral epicondyle to supermedial surface of tibia
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7
Q

what is swelling like in the Medial Collateral ligament (MCL)?

A

it is a capsular ligament therefore you will see big thick capsular swelling near 8hr afterwards

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8
Q

what are the second line of support for medial knee injuries?

A

the ACL and MCL

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9
Q

what are the cruciates of the knee?

A

1: the ACL
2: the PCL

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10
Q

where does the word “cruciates” come from?

A

means that the ligaments (ACL and PCL) cross

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11
Q

anatomy of the anterior cruciate ligament (ACL)

A
  • it runs from anterior aspect of tibial plateau to the posterior medial aspect of lateral femoral condyle.
  • primary restraint to anterior tibial translation
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12
Q

the greatest translation of the ACL occurs at

A

20-30 degrees

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13
Q

what are the 2 major bundles named for their attachment on the tibia of the ACL?

A

1: anteromedial - tighter in flexion
2: posterolateral - tighter in extension

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14
Q

ACL attachments

A
  • from anterior aspect of the tibial plateau to posterior medial aspect of lateral femoral condyle
  • 2 major bands:
    1: anteriomedial
    2: posterolateral
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15
Q

what is the stablizing role of the ACL

A

1: restrict posterior translation of the femur relative to the tibia during weight bearing (when it is fixed it stops the tibia from moving backwards)

2: restricts anterior translation of the tibia during non-weight bearing (stops it from moving forwards)

3: secondary support for VALGUS and VARUS with collateral ligament damage

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16
Q

anatomy of the posterior cruciate ligament (PCL)

A
  • the PCL orginates on the lateral aspect of the medial femoral condyle and inserts posteriorly to intercondylar area of tibia
  • larger and stronger than the ACL (so it doesn’t get injured as much)
  • primary restraint to posterior tibial translation
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17
Q

what degree is the greatest translation that occurs at the posterior cruciate ligament (PCL)?

A
    • 30 degrees
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18
Q

what are the 2 major bundles named for their attachment on the tibiafor PCL

A

1: anterolateral - tight in flexion

2: posteromedial - tight in extension

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19
Q

PCL attachments

A
  • from lateral aspect of medial femoral condyle
  • passes medial to ACL
  • inserts posteriorly to intercondylar area of tibia
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20
Q

stabilizing role of the PCL

A

1: functions to restrict anterior translation of the femur relative to the tibia during weight bearing

2: restricts posterior translation of the tibia during non-weight bearing

3: limits hyper-internal rotation

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21
Q

the meniscus

A
  • serve essential roles in maintaining knee function
    • stabilize knee by increasing concavity of tibia (deepens the socket and allows for the tibia to sit in it)
    • shock absorption
      (full extension 45-50% of load)
      (90 degree flexion 85% of load)
      (compression facilitates distribution of nutrients)
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22
Q

medial meniscus

A
  • C - shaped
  • larger radius of curvature (bigger and rounder)
  • tight connection with capsule and MCL
  • poor mobility (basically means it is stuck there because it is less mobile it might be more likely to be torn)
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23
Q

lateral meniscus

A
  • O shaped
  • smaller (tighter) radius of curvature
  • attached loosely to capsule and popliteal tendon
  • increased mobility
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24
Q

what muscle do you use for the first couple of degrees of knee flexion getting out of screw home

A

popliteus

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25
Q

meniscal fixation

A
  • significant disparity in the literature and between individuals
  • the menisci are fixed in place and prevented from extruding by coronary ligaments and anterior and posterior transverse meniscal ligaments
  • deep portion of capsule attached to periphery of meniscus
  • medial is thicker/tighter than the lateral (this is why it is less mobile)
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26
Q

meniscal blood flow

A
  • each meniscus can be divided into 3 different zones
    1: red-red zone
    2: red-white zone
    3: White - white zone
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27
Q

red- red zone

A
  • heals well because you are not cutting the meniscus and so it can heal nicely
  • has good blood supply - outer 1/3
28
Q

Red-white zone

A
  • minimal blood flow supply
  • middle 1/3
29
Q

white- white zone

A
  • is avasular
30
Q

clinical perspective of knee injuries

A

pretty much just doing SOAP (same as usual)

31
Q

area of pain in a knee assessment

A

1: medial: thinking ACL
2: lateral : thinking MCL
3: internal: thinking ACL PCL

32
Q

subjective knee assessment

A

mechanism of injury
- varus or valgus
- contact or non-contact

sounds (i.e. pop or crack this is when you think its a fracture )
continue to play/able to WB?
locking, giving way since (this is when you are thinking ACL mostly but it can also be other ligaments)

33
Q

swelling of knee injuries

A

nature of any swelling - hemarthrosis
- bleeding into the joint
- typically occurs more quickly than synovial effusion/capsular swelling
- noticeable swelling 2-6 hours post-injury
- >75% were ACL tears in adults
- patellar dislocation next most common (young)
- in paediatrics, suspect patellar dislocation

34
Q

Ottawa knee rules

A

x-ray series is only required for knee injury patients with any of the below

1: age 55 or older
(because you are worried about their bone density)
2: isolated tenderness of the patella
3: tenderness of the head of the fibula
4: cannot flex 90 degrees
5: unable to bear weight both immediately and in the emergency room department for 4 steps

35
Q

Acute patellar dislocation

A

MOI
- forceful knee rotation (tibia external rotation/ femur internal rotation) +- forceful quadriceps contraction
- knee usually near full extension (out of trochlea)
- +- laterally directed force

36
Q

patellar dislocation - symptoms

A
  • may report feeling knee “shift”, “move” or “pop out”
  • pain ++ until reduced
  • fast swelling (because you are tearing our a bunch of things)
37
Q

patellar dislocation - signs

A
  • loss of knee function (if still dislocated)
  • tenderness over medial border of patella
  • positive lateral apprehension text
38
Q

what test do you do with a patellar dislocation

A

lateral apprehension test

39
Q

3 layers of lateral support complex

A

1: superficial
2: middle
3: deep

40
Q

superficial layer of lateral support

A
  • iliotibial band and biceps femoris
41
Q

middle layer of lateral support complex

A
  • patellofemoral ligaments and retinaculum
42
Q

deep layer of lateral support complex

A
  • lateral (tibial) collateral ligament (LCL)
  • popliteus tendon
  • capsule
  • other ligaments (Arcuate, Fabellofibular, etc)
43
Q

Lateral Collateral Ligament (LCL)

A
  • LCL injuries are less common but more complicated secondary to the number of structures
  • usually varus loading +- hyperextension
  • ## most contribution at 20-30 degrees of knee flexion
44
Q

medial collateraal ligament - the facts

A
  • 40% of all severe knee injuries involve the MCL , making it the most frequently injured knee structure
  • valgus force with or without rotation
  • often occur in isolation
45
Q

signs and symptoms of collateral ligament sprains

A

swelling: timing
- minimal swelling LCL only - more if soft tissue is injured
- slow localized swelling medial side (grade 2+)
- capsular effusion > 8hrs

stress testing: in the same direction of MOI (done in 20-30 degrees because this is where you are looking for pain, laxity and endpoint)
- grade 1: pain with no laxity
- grade 2: pain with laxity. distinct end point
- grade 3: pain variable with gross laxity - no end point

46
Q

valgus goes with —
varus going with —

A

1: MCL
2: LCL

47
Q

ACL injuries

A
  • occurs with either contact or non-contact (60-80%) mechanism
  • usually during ocurring or single leg landing
  • may occur in isolation or in combination with other injury
  • 2-8 x higher injury rate in females
48
Q

are ACL injuries more common in females or males?

A

females

49
Q

what are the MOI of ACL injuries?

A

1: valgus after MCL - usually with contact

2: deceleration/internal rotation - non-contact

3: IT CAN NOT HAPPEN IN ISOLATION

4: quads active - anterior tibial translation

50
Q

can ACL injuries occur in isolation?

A

NO

51
Q

ACL injury: quads active mechanism

A

main mechanism
- rapid deceleration
- untoward landing

shoe - surface interface friction
anterior tibial dislocation by quads

52
Q

ACL - key findings on subjective examination

A

symptoms
- 80% describe an audible “pop” or “crack”
- can range from very painful to minimal pain
- usually unable to continue activity

hemarthrosis
> 75% 1-6 hours
- may report instability or giving way

53
Q

ACL objective findings (SIGNS)

A

signs
- restricted movement (especially extension)

lateral joint tenderness- often mistaken for LCL
- 80% lateral bone bruise or segond fracture

positive anterior drawer & lachmands positive
- graded like other ligaments

54
Q

what is the best test to do for ACL injuries?

A

lockmans test
- looking for the end point

can also do anterior drawer but it is not truly the best
- it can be worse because the hamstrings might help and make things look different

55
Q

posterior cruciate ligament injuries

A
  • strongest of the knee ligaments
  • only 1 in 10 cruciate injuries involve the PCL
  • usually sports injuries - but also common in MVA’s
56
Q

PCL Etiologogy/MOI

A
  • most common is a direct blow to upper portion of the tibia
  • fall on a flexed knee
  • MVA -dashboard injury or pre-tibial trauma

hyper-flexion
- increase tension in anterior segment
- impinged between posterior tibia + inracondylar notch roof

hyperextension

57
Q

PCL objective findings - signs

A

sings
- minimal swelling
- posterior drawer test is most sensitive
- graded like other ligaments
- sag test will be positive
- need to assess medial and lateral structures too!

58
Q

patellofemoral pain

A

pain in the peripatellar/retropatellar area that is aggrevated by at least one activity that loads the patellofemoral joint during weight bearing on a flexed knee
- pain walking down stairs
- pain with squatting
- pain following sitting for long periods
- running, jumping, hopping

59
Q

hypo pressure of the knee

A

the cartilage will degenerate from the inside out because it needs a certain amount of force to go through it to stay healthy

60
Q

hyper pressure

A

is ruined because of grinding

61
Q

propsed contributing INTRSINTIC factors

A

1: lower chain alignment
2: excessive pronation
3: poor multi-plane lumbo-pelvic/Pelvo femoral control (core, gluteus medius)
4: shortened muscles: hamstrings, ITB, calves and rectus femoris
5: pull of quads

62
Q

the lower chain alignment (q-angle)

A
  • if it is greater than 20 degrees it increases the risk of instability of PF joint
63
Q

excessive pronation of the knee

A
  • over pronation at the subtalar joint causes internal rotation of the tibia and delayed re-supination
  • this affects screw-home mechanism as tibia does not externally rotate
    • as such the femur must internally rotate more to get to extension
  • results in lateral pull on the patella
64
Q

poor multi-plane lumbo-pelvic/ pelvo femoral control (AKA medial collapse mechanism)

A
  • hip adduction, femoral internal rotation and knee valgus
  • change femur under patella
  • decrease contact area
  • increase joint stress
65
Q

vastus medialis dysfunction

A
  • sum of all 4 quads and tibial tendon are offset into valgus
  • theory that weak VMO will not be able to maintain alignment
    • slow
    • weak
      -altered line of pull

will cause abnormal pull on the patella.. overloading lateral side

66
Q

how do you treat for patellofemoral pain treatments?

A

pretty much do the normal phases
1: inital phase- POLICE/PEACE & LOVE

2: repair phase

3: remodeling phase

athletic injuries 2036 (20 decks)

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