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Athletic Injuries > Lecture 15 - Knee Injuries pt.2 > Flashcards

Lecture 15 - Knee Injuries pt.2 Flashcards

1
Q

What are the 3 layers of the Medial Support Complex

A
  1. superficial
  2. middle
  3. deep
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2
Q

what structures are found in the superficial layer of the medial support complex?

A
  • sartorius and fascia
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3
Q

what structures are found in the middle layer of the medial support complex?

A
  • superficial MCL and semimembranosis
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4
Q

what structures are found in the deep layer of the medial support complex?

A
  • deep fibres of the MCL and capsule
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5
Q

What contributes to the stability of the medial support complex?

A
  • MCL (strongest at 20-30 degrees) –> ACL and PCL are secondary vs. valgus
  • Muscle help in full extension –> medial hamstrings, medial head of gastrocs and quad muscles
  • Bony structure is tertiary support
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6
Q

What is the MCL?

A
  • medial collateral ligament
  • a capsular ligament (swells)
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7
Q

Where are the superficial and deep components of the MCL?

A
  • deep = connect directly to the medial meniscus
  • superficial = run from medial femoral epicondyle to superomedial surface of tibia
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8
Q

What is the distribution of knee structures resisting at 5 degrees?

A
  • superficial MCL = 57%
  • deep MCL = 8%
  • posterior oblique = 18%
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9
Q

what is the distribution of knee structures resisting at 25 degrees?

A
  • superficial MCL = 78%
  • deep MCL = 4%
  • posterior oblique = 4%
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10
Q

Where is the ACL located?

A
  • anterior aspect of tibial plateau to posterior medial aspect of lateral femoral condyle
  • “up and around”
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11
Q

what are the two bundles/bands of the ACL?

A
  • anteromedial –> tighter in flexion
  • posterolateral –> tighter in extension
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12
Q

What is the main role of the ACL?

A
  • primary restraint to anterior tibial translation
  • greatest translation occurs at 20-30 degrees (so test at this range)
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13
Q

What is the stabilizing role of the ACL?

A
  • restrict posterior translation of femur relative to the tibia during weight bearing
  • restrict anterior translation of tibia during non-weight bearing
  • limits excessive rotation of the tibia
  • secondary support for valgus and varus with collateral ligament damage
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14
Q

which of the cruciate ligaments is weaker?

A
  • the ACL
  • this is why it is injured so much easier/ more often
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15
Q

where is the PCL located?

A
  • originated on the lateral aspect of the medial femoral condyle and inserts posteriorly to the intercondylar area of the tibia
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16
Q

what are the two bundles/bands of the PCL?

A
  • anterolateral –> tight in flexion
  • posteromedial –> tight in extension
  • slight sideways translation at extension due to the screw home mechanism
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17
Q

what is the main role of the PCL?

A
  • primary restraint to posterior tibial translation
  • greatest translation occurs at 20-30 degrees
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18
Q

Where is the PCL located in relation to the ACL?

A
  • passes medial to the ACL
  • located posterior to the ACL
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19
Q

what is the stabilizing role of the PCL?

A
  • restricts anterior translation of the femur relative to the tibia during weight bearing
  • restricts posterior translation of the tibia during non-weight bearing
  • limits hyper-internal rotation
  • secondary support for valgus and varus with collateral ligament damage
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20
Q

what is the role of the meniscus?

A
  • an essential role in maintaining knee function
  • stabilize knee by increasing concavity of tibia (more depth so more stability)
  • shock absorption (full extension = 45-50% of load, 90 degree flexion = 85% of load)
  • compression facilitates distribution of nutrients
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21
Q

compare and contrast the medial and lateral meniscus

A

Medial
- c-shaped
- large radius of curvature
- tight connection with capsule and MCL
- poor mobility
- many issues/ bad news

Lateral
- O-shape
- small (tighter) radius of curvature
- loose connection with capsule and popliteal tendon
- increased mobility

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22
Q

What is meniscal fixation?

A
  • menisci are fixed in place and prevented from extruding by coronary ligaments and anterior/posterior transverse meniscal ligaments
  • deep portion of capsule attached to periphery of meniscus
  • medial is thicker/tighter than lateral
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23
Q

Which menisci is injured first and why?

A
  • medial injures first and often (because tighter)
  • lateral injuries are more catastrophic due to how mobile it is
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24
Q

What are the three different zones of the Menisci?

A
  • red-red zone
  • red-white zone
  • white-white zone
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25
Q

what are the characteristics of the red-red zone?

A
  • good blood supply
  • outer 1/3
  • heals easier (stitches and rehab/recovery)
  • will supply
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26
Q

what are the characteristics of the red-white zone?

A
  • minimal blood supply
  • middle 1/3
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27
Q

what are the characteristics of the white-white zone?

A
  • no blood supply/ avascular
  • inner 1/3
  • will not heal on its own, removal/cut out
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28
Q

what is the goal of clinical perspective in knee injuries?

A
  • to assess knee and determine degree of injury
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29
Q

what must you consider in a clinical perspective?

A
  • subjective findings and objective examination findings
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30
Q

what might you look for in subjective findings?

A
  • area of pain (medial vs. lateral vs. deep)
  • MOI (varus or valgus, contact or non-contact)
  • sounds (pop or crack)
  • locking? (meniscus usually)
  • did you see it coming? (last second turning to avoid hit)
  • pain and disability at time of injury
  • presence and timing
  • onset of swelling
  • degree of disability (could they continue?, could they stand?)
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31
Q

what might you look for in objective examination findings?

A
  • observation
  • STTT
  • special tests (could include neuro)
  • palpation
32
Q

What is hemarthrosis?

A
  • bleeding into the joint
  • quick swelling (noticeable usually within the first 2 hours)
33
Q

What percentage of knee assessments result in ACL tear diagnosis in adults?

A
  • > 75%
34
Q

what is the most common knee injury in young (11-14) patients?

A
  • patellar dislocation
  • then fractures and meniscal tears
35
Q

why is it important to learn the past trauma of patients?

A
  • because when checking for swelling and dislocations, would need to know past injuries in case one side looks/feels different
36
Q

What are Ottawa Knee Rules?

A

A knee X-ray is only required if any of the following:
- age 55 or older (bone density)
- isolated tenderness of the patella (and nowhere else in the knee)
- tenderness of the head of the fibula
- cannot flex to 90 degrees
- unable to bear weight immediately and in ER for 4 steps (regardless of limping)

37
Q

what type of patella dislocation is more common?

A
  • lateral dislocation
38
Q

what is a patella dislocation?

A
  • when the patella moves out of its groove (usually laterally) onto/over the femoral condyle
39
Q

What is the MOI of acute patella dislocation?

A
  • forceful knee rotation (tibia ER/femur IR) +/- forceful quadriceps contraction
  • knee usually near full extension (out of trochlea)
  • +/- laterally directed force
40
Q

What are the symptoms of a patellar dislocation?

A
  • a possible feeling of “knee shift”, “move” or “pop out”
  • pain ++ until reduced (less pain once put back in place)
  • fast swelling (hemoarthrosis)
41
Q

what are the signs of a patellar dislocation?

A
  • loss of knee function (if still dislocated)
  • tenderness over the medial border of the patella (bc. torn everything medially for it to shift)
  • positive lateral apprehension test
  • need to R/O ACL (because would also have swelling and similar subjective findings)
42
Q

how do you put a dislocated knee back in place?

A
  • relocate at the same position as MOI
  • slightly flex the hip
  • slowly extend the knee
  • should relocate on its own (if it doesn’t do not force it, might be an underlying fracture)
  • always send for X-Rays immediately
43
Q

What are the 3 layers of the lateral support complex?

A
  • superficial
  • middle
  • deep
  • and support from muscles
44
Q

what are the structures of the superficial layer of the lateral support complex?

A
  • iliotibial band and biceps femoris
45
Q

what are the structures of the middle layer of the lateral support complex?

A
  • patellofemoral ligaments
  • retinaculum
46
Q

what are the structures of the deep layer of the lateral support complex?

A
  • lateral (tibial) collateral ligament (LCL)
  • popliteus tendon
  • capsule
  • other ligaments
47
Q

What is the MOI of an LCL injury?

A
  • less common but more complicated
  • usually varus loading +/- hyperextension
  • most contribution at 20-30 degrees of knee flexion
  • may include ITB, lateral hamstrings and/or popliteus (test these too because usually injured with LCL)
48
Q

What is the MOI of lateral spread?

A
  • usually varus
49
Q

what is the MOI of medial spread?

A
  • usually valgus
50
Q

What is the MOI of an MCL injury?

A
  • most frequently injured knee structure (40% involve MCL)
  • valgus force with or without rotation
  • often occur in isolation (without other structures getting injured)
51
Q

What are the signs/symptoms of collateral ligament sprains?

A
  • pain over structure
  • minimal swelling = LCL
  • slow localized swelling = MCL
  • stress testing = in same direction of MOI (for either)
  • valgus stress = MCL (tested at 0 and 20-30 degrees)
  • varus stress = LCL (tested at 20-30 degrees)
  • graded 1-3
52
Q

what are the characteristics of each grade of a sprain?

A
  • grade 1 = pain with no laxity
  • grade 2 = pain with laxity, but a distinct end point
  • grade 3 = pain variable with gross laxity and no endpoint
53
Q

What are the common mechanisms of ACL Injuries?

A
  • contact or non-contact mechanism
  • usually during cutting or single limb landing
  • may occur in isolation or with other injuries
  • 2-10x higher rate in females
54
Q

what other injuries may occur with an ACL injury?

A
  • 75% meniscal injuries
  • 80% have bone bruise on lateral joint line (lateral knee pain from bones hitting each other)
55
Q

What are the four MOIs of ACL tear?

A
  1. valgus after MCL - usually with contact
  2. deceleration/internal rotation - non-contact
  3. hyper-extension (not straight hyperextension unless everything else is also torn)
  4. quads active - anterior tibial translation (quads fire more than hamstrings)
56
Q

what is the quads active mechanism of ACL injury?

A
  • rapid deceleration and untoward landing
  • shoe- surface interface friction
  • anterior tibial dislocation by quads (hamstrings not on)
  • causes bone bruising
57
Q

what are the symptoms of ACL tears?

A
  • ~80% describe an audible pop/crack
  • range from very painful to minimal pain
  • usually unable to continue activity
  • hemarthrosis (> 75% 1-6 hours)
  • instability/ giving way
58
Q

what are the signs of ACL tears?

A
  • restricted movement (especially extension)
  • lateral joint tenderness (mistaken for LCL) - 80% have a lateral bone bruise or segond fracture
  • positive anterior drawer and Lachman’s tests (which is better than anterior drawer because of hamstrings being inactivated)
  • graded like other ligaments (pain, endpoint, laxity)
59
Q

what are the common characteristics of posterior cruciate ligament injuries?

A
  • strongest of the knee ligaments
  • 1/10 are PCL tears (9/10 are ACL)
  • ~60% include injuries to other structures (usually meniscal tears)
  • usually sports injuries but also common in MVA (motor vehicle accidents)
60
Q

What are the common MOIs of PCL injuries?

A
  • direct blow to the upper portion of the tibia (fall on flexed knee or MVA dashboard trauma)
  • hyper-flexion (increased tension in anterior segment and impingement)
  • hyperextension
61
Q

what are the symptoms of PCL injuries?

A
  • feeling of a pop in the posterior knee
  • poorly defined pain in the back of the knee
  • minimal swelling at time of injury
62
Q

what are the signs of PCL injuries?

A
  • minimal swelling
  • posterior drawer test (tibia will fall back)
  • sag test will be positive (shin sags in leg up crunch position if PCL is gone)
  • need to assess medial and lateral structures as well
63
Q

what is patellofemoral pain?

A
  • pain in the peripatellar/retropatellar area that is aggravated by at least one activity that loads the patellofemoral joint during weight bearing on a flexed knee
64
Q

what are examples of flexed knee activities that may trigger pain with PFP?

A
  • pain walking down the stairs
  • pain with squatting
  • pain following sitting for long periods
  • running, jumping, hopping
65
Q

what are the statistics of patellofemoral pain?

A
  • 10-25% of all PT visits are for patellofemoral pain syndrome
  • conflicting evidence
  • evaluating overuse injuries to identify factors that may contribute to the condition
66
Q

what are the possible causes of PFP?

A
  • uneven pressure distribution across the back of the patella
  • medial hypo-pressure = cartilage degeneration from inside-out
  • lateral hyper-pressure = cartilage rub and fibrillation
67
Q

what are the 5 proposed intrinsic factors of PFP?

A
  1. lower chain alignment
  2. excessive pronation
  3. poor multi-plane lumbo-pelvis/pelvo femoral control (core and glutes)
  4. shortened muscles (it band, hamstrings, calves, and rectus femoris)
  5. pull of quads
68
Q

How does lower chain alignment cause PFP?

A
  • valgus Q angle
  • greater Q angle = greater lateral pull
  • q angle > 20 increases risk of instability of PF joint
  • can cause PFP syndrome, OA and ITB friction syndrome
69
Q

How does excessive pronation cause PFP?

A
  • over-pronation at the subtalar joint causes internal rotation of the tibia and delayed re-supination
  • affects screw-home mechanism (tibia can’t externally rotate)
  • femur is forced to internally rotate more to get to extension
  • causes lateral pull on the patella
70
Q

what is medial collapse mechanism?

A
  • hip adduction, femoral knee rotation and knee valgus
  • change femur under patella (decreased joint contact area and increases joint stress)
  • pull on IT band to more patella
71
Q

how does shortened muscles cause PFP?

A
  • quads = increased compression of PF joint
  • hamstrings = require increase in quads force production to overcome length issue
  • IT band = increases pressure over the lateral surface of the trochlear groove, moves over femoral condyle at 25-30 degree flexion
  • gastrocs and soleus = limit dorsiflexion, compensated with excessive rotation of lower leg and altered Q angle
72
Q

what is vastus medialis dysfunction?

A
  • sum of all 4 quads and tibial tendon are offset into valgus
  • weak oblique VM will not be able to maintain alignment (slow, weak, altered line of pull)
  • will cause abnormal pull on the patella (will pull sideways or at 45, want it to pull straight up)
73
Q

what are PFP pain treatments?

A
  • identify and correct the intrinsic and extrinsic issues
  • difficult to manage
  • different for each individual
74
Q

what are the pain treatments for the 3 phases?

A
  • initial phase = police/peace and love, relative rest, palliate pain, decrease swelling and identify issues
  • repair phase = correct biomechanical issues (muscle length, muscle strength and function)
  • remodeling phase = slowly increase FIIT
75
Q

what are the evidence-based practice tips for PFP rehab?

A
  • daily exercise of 2-4 sets of >10 (20-30) reps for 6 weeks (for running/jumping athletes)
  • patellar taping and knee bracing (if it works, if not, don’t do it)

Athletic Injuries (13 decks)

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