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Kin 2236 Athletic Injuries > (3) Lecture 15: Knee 2.0 > Flashcards

(3) Lecture 15: Knee 2.0 Flashcards

1
Q

Medial Support Complex Layers

A

3 layers

Superficial: Sartorius and fascia
Middle: superficial MCL and semimembranosus
Deep: deep fibres of MCL and capsule

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2
Q

Medial Support Complex Stability

A

Primary stabilizer: MCL - 25 to 30 degrees
- ACL/PCL secondary

Bony structure is tertiary support

Muscles help in full extension
- medial hamstrings (sartorius, semimemb, semitend.)
- medial head of gastrocs
- quad muscle - vastus med.

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3
Q

MCL Components

A

CAPSULAR = swelling

Has superficial and deep components
- deep: connect directly to medial meniscus
- superficial: run from medial femoral epicondyle to superomedial surface of tibia

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4
Q

Contribution by Structure to Medial Knee Injuries

A

AT 25 degrees
- most from superficial MCL then crucoiates

AT 5 degrees
- most from superficial MCL (less than at 25) then post capsule then cruciates

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5
Q

Anatomy of ACL

A
  • runs from anterior aspect of tibial plateau to posterior medial aspect of lateral femoral condyle

2 major bundles named for attachment on tibia:
- anteromedial - tighter in FLEXION (heat-sensitive)
- posterolateral - tighter in EXTENSION

PRIMARY RESTRAINT TO ANTERIOR TIBIAL TRANSLATION

greatest translation at 20 - 30 degrees

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6
Q

Stabilizing role of ACL

A

WEAKER of two cruciates

  • restricts POSTERIOR translation of FEMUR relative to tibia during WEIGHT BEARING
  • restricts ANTERIOR translation of TIBIA during NON-weight bearing
  • also limits excessive rotation of tibia

secondary support for VALGUS and VARUS w/ collateral lig. damage

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7
Q

Heat sensitive view of ACL

A

anteromedial bundle tightens in FLEXION
posterolateral bindle tightens in EXTENSION

WHITER = MORE ON STRETCH

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8
Q

Anatomy of PCL

A
  • originates on lateral aspect of medial femoral condyle and inserts posteriorly to intercondylar area of tibia

2 major bundles named for attachment on tibia:
- anterolateral: tight in FLEXION (larger)
- posteromedial: tight in EXTENSION

LARGER AND STRONGER than ACL

  • primary restraint to POSTERIOR tibial translation
  • GREATEST translation at 20-30 degrees
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9
Q

Stabilizing role of PCL

A

STRONGER of cruciate ligs

  • restricts anterior translation of femur relative to the tibia during weight beating (foot planted)
  • restricts posterior translation of tibia during NON-weight bearing
  • limited HYPER-INTERNAL ROTATION
  • secondary support for valgus + varus w/ collateral lig damage
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10
Q

Collaterals supports

A

Lateral primary support = MUSCLES
Medial primary support = MCL

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11
Q

Meniscus

A
  • once believed to be a useless remnant of intra-articular attachments
  • stabilize knee by increasing concavity of tibia

Shock absorption
- full extension (45-50% of load)
- 90 degree flexion (85% of load)
- compression facilitates distribution of nutrients

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12
Q

Medial vs Lateral Meniscus

A

Medial Meniscus - LOTS of issues (more injured)
- C-shaped
- larger radius of curvature
- tight connection w/ capsule + MCL
- POOR MOBILITY
- ex. Tutanic

Lateral Meniscus - less injured but more CATASTROPHIC
- O shape
- smaller radius of curvature
- attached loosely to capsule + POPLITEAL TENDON
- increased mobility
- ex. speedboat

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13
Q

Meniscal Fixation

A
  • menisci are fixed in place + prevented from extruding by CORONARY ligaments and anterior + posterior transverse meniscal ligaments
  • deep portion of capsule attached to periphery of mensicus
  • medial is THICKER/TIGHTER than lateral
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14
Q

Meniscal Blood Flow

A

Divided into 3 zones:
- RED zone: good blood supply - outer 1/3
- RED-WHITE zone: minimal blood supply - middle 1/3
- WHITE zone: avascular

Outer injuries heal better b/c of good blood flow
Inner injuries are usually cut out b/c they won’t heal

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15
Q

Subjective Knee Assessment

A

Area of pain - medial, lateral, internal?

Mechanism of Injury
- Varus or Valgus (valgus: hit on outside + stretch inside)
- Contact or non-contact (if non-contact: decelerating, cutting, landing?)

Sounds (i.e. “pop” or “crack”)

Continue to play/able to weight bear (WB)?

Locking (meniscal), giving way since (ligamentous, muscle, etc)

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16
Q

Knee Swelling - Subjective Assessment

A

Nature of swelling - hemarthrosis?

Noticeable swelling 2-6 hours post-injury
- >75% of adults - ACL tear
- Young (13-14) most common is patellar dislocation
- Pediatrics - suspect patellar dislocation

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17
Q

Hemarthrosis

A

Fast swelling
- bleeding into joint
- typically occurs more quickly than synovial effusion/capsular swelling

Ex. ACL, red-red mensicus, patellar dislocation

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18
Q

Ottawa Knee Rules

A

Knee X-Ray is ONLY needed for knee injuries w/ any of these findings:
- age 55 or older
- isolated tenderness of patella (no other bone tenderness)
- tenderness of head of fibula (2-3 in. lateral from tib. tuberosity)
- cannot flex to 90 degrees
- unable to bear weight for 4 STEPS (unable to TRANSFER WEIGHT TWICE onto each lower limb regardless of limping)

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19
Q

Subluxed or Dislocated Patella

A

generally dislocates LATERALLY

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20
Q

Acute Patellar Dislocation MOI

A
  • forceful knee rotation (tibia ER/femur IR) +/- forceful quad contraction
  • knee usually near full extension (out of trochlea) - patella moves UP in extension
    +/- laterally directed force
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21
Q

Symptoms of Patellar Dislocation

A
  • may report feeling knee “shift”, “move” or “pop out”
  • LOTS OF PAIN UNTIL REDUCED
  • FAST swelling = hemarthrosis
22
Q

Signs of Patellar Dislocation

A
  • loss of knee function (if still dislocated)
  • tenderness over MEDIAL border of patella
  • POSITIVE LATERAL APPREHENSION TEST

NEED TO R/O ACL –> b/c of similar subjective findings - hemarthrosis, shift/move/pop

23
Q

Patellar Dislocation Treatment

A

Slightly FLEX HIP and slowly EXTEND THE KNEE
- takes tension off quads - easier to reduce
- usually patella relocates. If not, do NOT force the patella medial

send for X-rays immediately

24
Q

Lateral Support Complex

A

3 layers
Superficial: ITB and biceps femoris
Middle: patellofemoral ligs and retinaculum
Deep:
- LCL
- popliteus tendon
- capsule

MAIN SUPPORT FROM MUSCLES

25
LCL
- injuries are less common but more complicated - usually VARUS (force on medial side) loading +/ hyperextension - most contribution at 20-30 degrees of knee FLEXION - may include ITB, lateral hamstrings and/or popliteus
26
Varus force vs valgus loading
Varus loading - force on medial side Valgus: hit on outside + stretch inside
27
MCL Facts
- 40% of all severe knee injuries involve MCL - MOST FREQUENTLY INJURED knee structure - VALGUS force +/- rotation - often occurs in ISOLATION (unlike lateral)
28
Signs and symptoms of collateral ligament sprains
reports of pain over structure Swelling? Timing? - slow localized swelling on medial side (grade 2+) -- capsular effusion > 8 hrs Stress testing: in SAME DIRECTION of MOI - valgus stress for MCL and varus stress for LCL - Grade 1: pain w/ no laxity - Grade 2: pain w/ laxity; distinct endpoint - Grade 3: pain variable; gross laxity; no endpoint
29
ACL injuries
- can be contact or non contact (60-80% non-contact) usually during cutting or single leg landing - may occur in isolation or in combo w/ other injury (75% have meniscal injury; 80% have bone bruise on lateral jt line or Segond Fracture) 2-8x higher injury rate in females
30
ACL MOI
1. Valgus after MCL - usually w/ contact 2. Deceleration/internal rotation - non-contact 3. Quads Active - anterior tibial translation (quads fire more than hamstrings - more common in FEMALES) NOT hyperextension - doesn't happen in isolation
31
Quads Active ACL MOI
no co-contraction from hamstrings Main mechanisms - rapid deceleration - untoward landing anterior tibial dislocation by quads
32
Symptoms of ACL injury
- 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
33
Signs of ACL injury
- restricted movement - especially extension - lateral joint tenderness - often mistaken for LCL (80% have lateral bone bruise or Segond Fracture) - POSITIVE ANTERIOR DRAWER + LACHMAN'S TEST (LACHMAN > ANT. DRAWER) - Lachman @ 20-30 degrees of flexion
34
PCL Injuries
- STRONGEST of knee ligaments - only 1 in 10 cruciate injuries involve PCL - 60% include injuries to other structures - usually sports injuries but also common in MVAs
35
PCL MOI
Most common: DIRECT BLOW to upper portion of tibia - fall on flexed knee - MVA - dashboard injury or pre-tibial trauma Hyper-flexion - increased tension in anterior segment - impinged btwn posterior tibia + intracondylar notch roof Hyperextension
36
Signs of PCL Injury
- MINIMAL swelling - POSTERIOR DRAWER test = most sensitive - SAG TEST will be positive - assess medial and lateral structures too
37
Malalignment Syndromes/Overuse Knee Injuries/Patellofemoral Pain
- tendinosis - osteoarthritis - runner's knee - chondromalacia - ITB friction syndrome - Patellofemoral Pain Syndrome - jumper's knee
38
PFP
Patellofemoral Pain - pain in peripatellar/retropatellar area that is aggravated by at least one activity that loads the patellofemoral jt during weight bearing on a flexed knee - pain walking down stairs - pain with squatting - pain following sitting for long periods - running, jumping, hopping patients w/ PFPS are 10-25% of PT visits
39
Causes of PFP
- HYPO-pressure on medial aspect of patellofemoral jt - HYPER-pressure on later aspect - results in cartilage degeneration from inside-out - results in cartilage rub and fibrillation
40
Proposed contributing INTRINSIC factors
1. Lower chain alignment 2. Excessive pronation 3. Poor multi-plane lumbo-pelvic/pelvo femoral control (core, glut. medius) 4. Shortened muscles: hamstrings, ITB, calves and rectus femoris 5. Pull of quads
41
Lower Chain alignment and PFP
VALGUS alignment is common for PFP Load bearing axis on outside = pushing in (knocked knees)
42
Q-Angle
- axis formed by femur and tibia - greater Q angle = greater lateral pull - Q angle > 20 degrees = increased risk of instability of PF jt - can be factor in PFPS, OA, ITB friction syndrome (varus)
43
Medial Collapse Mechanism
poor multi-plane lumbo-pelvic/pelvo femoral control - hip adduction, femoral internal rotation and knee valgus (lateral pull on patella) change femur under patella - less joint contact area - more joint stress
44
Shortened muscles
Tight muscles crossing the knee may cause altered function Quads, hamstrings, ITB, triceps surae
45
Shortened quads
increased compression of PF joint during physical actibity
46
Shortened hamstrings
antagonist to quads will need increased quads force production to overcome length issue
47
Shortened ITB
lateral influence on patella = more pressure over lateral surface of trochlear groove must move over femoral condyle at 25-30 degrees flexion
48
Shortened triceps surae
triceps surae: gastrocs + soleus limit ankle dorsiflexion, which is often compensated for by excessive rotation of lower leg - altered Q angle
49
Vastus medialis dysfunction
- sum of all 4 quads and tibial tendon are set into valgus - theory that weak VMO will not be able to maintain alignment causes abnormal pull on patella - overloading lateral side
50
PFP Treatment
Initial phase - PEACE & LOVE/POLICE - palliate pain, decrease swelling, identify training issues Repair phase - correct biomechanical issues - look at muscle length, strength and function Remodeling phase - slowly increase training frequency and intensity
51
Evidence Based Tips for PFP Rehab
- prescribe daily exercises of 2-4 sets of 10+ reps over a period of 6+ weeks - consider higher reps for PFP patients who do lots of running and jumping - conflicting research about knee braces and oatellar taping - some evidence for prefabricated foot orthoses w/ regard to reducing short term pain

Kin 2236 Athletic Injuries (20 decks)

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