Second Midterm - Week 6 knee Flashcards
What three joints make up the knee complex?
- tibiofemoral joint (posterior)
- tibiofibular joint
- patellofemoral joint (anterior)
The femoral condyles are separated by a fossa and are egg shaped. It has a larger (anterior/posterior) radius and a smaller (anterior/posterior) radius
Larger anterior radius
Small posterior radius
The femoral condyles have a divergent axes of motion which creates conjoint rotation. What is the screw home mechanism?
The tibiofemoral joint rotates around the lateral condyles
(Tibia externally rotates and femur internally rotates to lock the knee into extension and visa versa. This maximally stabilizes the knee)
Which femoral condyle has a larger and longer articular surface?
Medial condyle
Which femoral condyle has a smaller epicondyle?
Lateral condyle
Which femoral condyle is more obliquely orientated?
Medial condyle
Which femoral condyle extends more distally?
Medial condyle
When the knees are anatomically touching but the ankles are not (knock-knees), this is called genu _____
Valgum
When the knees are anatomically distant but the ankles are touching (bow-legged), this is called genu ______
Varum
A normal medial twist of the knee is _____ degrees
10-20
Anteverted femur is _____ degrees. This correlates with genu ______ and a (medial/lateral) orientation
> 20
Genu valgum
Medial orientation
Retroverted femur is _____ degrees. This correlates with genu ______ and a (medial/lateral) orientation
<10
Genu varum
Lateral orientation
The tibial condyles are the flat superior surface. The tibial spine provide attachment points for WHAT THREE STRUCTURES and what is their FUNCTION
- ACL/PCL and meniscus
- help stabilize the knee
Which tibial condyle is larger?
Medial tibial condyle
T/F the tibial condyles are concave
F they are flat
The medial and lateral articular surfaces of tibial condyles are separated by ________
Intercondylar eminence
What are the fibrocartilage shock absorbers that sit on the surface of tibial condyles and what are their functions (4)
- medial and lateral menisci
- deepen the articular surface to increase stability
- Makes a flexible socket to condyles
- Accommodate slide and decrease shear stress
- Reduce wear and tear
The slight posterior ngulation of the condyles helps to ________
Prevent hyperextension
External tibial torsion may be responsible for foot _____
Foot flare
What type of cartilage lines the patellar surface of the femur?
Hyaline cartilage
T/F the patellar surface of the femur is anterior to the condyles
T
On the patellar surface of the femur the lateral facet is (smaller/larger) and the lateral lip is (shorter/taller) than the medial?
Larger
Taller
What is the main function of the patella?
Increase the angular pull of the quads
The lateral facet on the patella is (smaller/larger) than the medial?
Larger
The patella has the (thinnest/thickest) cartilage in the body?
Thickest
Patella Baja is when the patellofemoral ratio is _____
<0.8 and the patella is too distal to the knee
Patella Alta is when the patellofemoral ratio is ______
> 1.2 and the patella is too proximal to the knee
What makes up the patellofemoral ratio X:Y or X/Y?
X = length of the infrapatellar tendon Y = S-I diameter of patella
During flexion, the patella glides _________ and __________ in the patellar sulcus.
Inferior and posterior
How much contact between the patella and femur exists when the knee is in flexion at
- 0 degrees
- 30 degrees
- 60-90 degrees
- 135 degrees
- no contact
- Inferior pole of patella contacting superior part of condyles
- max contact
- superior pole of patella contacting inferior aspect of condyles. And the odd medial facet contact
At what degree of flexion is the max contact between the patella and femur?
60-90 degrees
At what degree of flexion is the odd medial facet in contact with the femur
135
At what degree of flexion is the inferior pole of the patella in contact with the femur? What about the superior pole?
30
135
What two intersecting lines create the patellofemoral Q-angle?
- ASIS -> center of patella
- center of patella -> tibial tuberosity
What is the normal range of patellofemoral Q-angle? For women? For men?
5-15
Women = 10-12
Men = 8-10
The patellofemoral Q-angle represents the pull of the ______
Quads
Genu varus (increases/decreases) the Q angle? Genu Valgum (increases/ decreases) the Q angle?
Decreases
Increases
The patella is less stable when
- knee is (flexed/extended)
- VMO is (weak/strong)
- Genu _______
- vastus lateralis is (too loose/too tight)
- patella is (too small/too large)
- patellar facet angle is (too flat/too angled)
- (small/large) lateral lip or (deep/shallow) groove
- patella (baja/alta)
- (internally/externally) rotated tibia
- (decreased/increased) foot flare
- excessive foot (pronation/supination)
- Knee EXTENDED
- VMO WEAK
- Genu VALGUM
- VL too TIGHT
- Patella too SMALL
- Patellar facet angle too FLAT
- SMALL lateral lip or SHALLOW groove
- Patella ALTA
- EXTERNALLY rotated tibia
- INCREASED foot flare
- Excessive foot PRONATION
What type of cartilage is the meniscus?
Fibrocartilagenous
A partial meniscectomy creates ______% increase in wear and tear. A full meniscectomy creates _____%
50-60
100+
The shape of the medial menisci is (C/O)? The lateral menisci is (C/O) shaped?
Medial = C Lateral = O
Which menisci is thinner and more fixed? Which is stronger and more mobile?
Medial
Lateral
Which menisci is more often injured?
Medial
The lateral menisci makes up ____% of menisci tears?
25
The MCL and semimbranosus tendon attach to the ____ menisci
Medial
The popliteus attached to the ____ meniscus
Lateral
Which ligament arises form the posterior horn of the lateral meniscus travels anterior to the PCL and attaches to the lateral surface of the medial condyle of the femur?
Anterior meniscofemoral ligament (Humphrey)
*The posterior meniscofemoral ligament (Wrisberg) travels posterior to the PCL
During flexion, the menisci slide (anterior, posterior). Which moves more, the lateral or medial?
Posterior
Lateral moves more
During flexion, there is more focal weight on the (anterior/posterior) horns of the menisci ?
Posterior
Deep squats increase stress on the (anterior/posterior) horns of the menisci?
Posterior
During flexion, synovial fluid is squeezed (anterior, posterior) in the menisci?
Posterior
During extension the menisci slide (anterior/posterior)? Which moves more, the lateral or medial
Anterior
Lateral moves more
During extension the (medial/lateral) menisci deforms more?
He medial deforms more
**attached to the MCL
At full extension, there is (more/less) total pressure on the menisci and (more/less) focal pressure?
More total
Less focal
During extension, the synovial fluid in the menisci is pushed (anterior/posterior)
Anterior
T/F menisci rotate with the femur
T
*abnormal motion leads to tears
During tibial internal rotation, the medial meniscus rotates (anterior/posterior) which increases the pressure.
The lateral meniscus moves (anterior/posterior)
Anterior
Posterior
During tibial external rotation, the medial meniscus rotates (anterior/posterior)
The lateral meniscus moves (anterior/posterior) which increases the pressure
Anterior
Posterior
Genu varus pinches he (medial/lateral) meniscus & tractions the (medial/lateral) meniscus through coronary ligaments
Medial
Lateral
Genu valgum pinches he (medial/lateral) meniscus & tractions the (medial/lateral) meniscus through coronary ligaments
Lateral
Medial (also through the collateral ligament)
Which part of the menisci has a blood supply?
Outer 1/3 in young and healthy
Are the menisci innervated?
Yes for pain and proprioception
What affect does aging have on the menisci? (3)
- decreased vascularization
- increased wear and tear
- increased friability
Where does the MCL attach? It resists (valgus/varus) stress
Medial femoral condyle & medial tibial condyle
*hence aka tibial collateral ligament
Valgus
How is the MCL sprained?
Direct blow to the lateral side of the knee
External rotation force (twisting)
Where does the LCL attach? It resists (valgus/varus) stress?
Lateral femoral epicondyle & fibular head
*hence aka fibular collateral ligament
Varus
How is the LCL sprained?
- Direct blow to the medial side of the knee
- hyper extension
Medial rotation (increases/decreases) tension on collaterals? Lateral rotation?
Decreases
Increases
The ACL and PCL are (intra/extra)capsular, (intra/extra)synovial and support vessels for nutrients
Intracapsular
Extrasynovial
Where does the ACL attack?
Anterior tibial plateau and tibial spine & the medial aspect of the lateral femoral condyle
The ACL is (larger/smaller) than the PCL
Smaller
The ACL is always tense because the (anterior/posterior) band is taut in flexion and the (anterior/posterior) band is taut in extension
Anterior
Posterior
T/F the ACL is not vascularized?
False. It is highly vascularized and the knee will fill with blood if it is torn
The ACL resists (anterior/posterior) translation of the tibia
Anterior
What is the most common serious ligament injury to the knee?
ACL
___ of all knee hemiarthrosis involve the ACL
3/4
What is the test for ACL
Anterior drawer test: anterior tibial translation joint play (anterior glide)
Where does the PCL attach?
Posterior tibial plateau and posterior tibial spine & lateral aspect of the medial femoral condyle
The PCL is ____________ in relation to the ACL
Posteromedial
The PCL is __ times as strong as the ACL
2x
The PCL is always tense but is lest tense at ____ degrees of flexion
25-40
*it also has two parts like the ACL
Which crucial ligament is lest likely to require surgery?
PCL
The PCL resists (anterior/posterior) translation of the tibia
Posterior
How can you see if a PCL is torn? (2)
- posterior sag sign
- posterior drawer test: posterior tibial translation join play (posterior glide)
The cruciates twist around each other in (internal/external) rotation of the femur?
Internal
*helps lock out with screw home mechanisms during extension
Which cruciate is weaker and more likely to tear due to internal rotation?
ACL
The cruciates untwist during (internal/external) rotation of the femur?
External
*help to unlock during takeoff
The IT blends with the __________ and attaches to ______
Lateral retinaculum
Gerdy’s tubercle
A tight IT band rubs on the lateral femoral condyle and pulls on the ______. This is called ______
Patella
ITB syndrome
The posteriormedial capsular complex consist of what 3 things?
- posterior part of MCL
- semimebranosus tendon
- oblique popliteal ligaments
The posteriomedial capsular complex resists:
- hyper (extension/flexion)
- (anterior/posterior) translation
- (varus/valgus) stress
- extreme rotation: lateral (>/
- hyperextension
- anterior translation
- valgus stress
- extreme rotation (lateral >medial)
The posterolateral capsular complex consists of? (6)
- LCL
- poplitiofibular ligament (PFL)
- arcuate ligament
- biceps femoris tendon
- popliteus
- ITB
The Posterolateral capsular complex resists:
- hyper (extension/flexion)
- (anterior/posterior) translation
- (varus/valgus) stress
- extreme rotation: lateral (>/
- hyper extension
- anterior translation
- varus stress
- extreme rotation: medial > lateral
What does the PFL stand for? It _____ during flexion and helps provide support to the knee
Poplitiofibular ligament
- tenses
What 4 bursa/cysts is the joint cavity connected to?
- Suprapatellar bursa
- popliteal bursa
- bakers cyst (aka popliteal cyst)
- gastrocnemius bursa
What 4 bursa are not connected to the joint cavity?
- pre-patellar
- infrapatellar
- pes anserine
- ITB
What ”ligaments” are actually extensions of he quadriceps tendon?
Medial and lateral retinaculum
Valgus sprain and patellar dislocations tear the (medial/ lateral) retinaculum?
Medial
Weak or stretched (medial/lateral) retinaculum OR tight (medial/lateral) retinaculum can cause patellar instability
Medial
Lateral
What is the synovial plica?
Remnant embryonic sac
*most are small and asymptomatic
Which one has more co-contracted, closed or pen chain?
Closed
Increased velocity = (increased/decreased) co-contraction of antagonist
Increased
What is the balance between quads and hamstrings ratio?
~60:40
VMO is most important to ______ stability
Patellar
Muscle contraction is _____ stability
Dynamic
* they are secondary stabilizers
Walking on a stable surface produces _____ BW on quad tension.
- Jogging = ?BW
- sprinting = ?BW
- jumping = ?BW
1x
- 5x
- ~7x
- > 10x
The patella increases extensor leverage ___% when knee is flexed 90-120
13
The patella increase extensor leverage ___% when the knee is flexed 0-5
31
What is PERCENTAGE of BW on quadriceps force during squats at the following degrees:
- 5
- 15
- 30
- 45
- 75
- 30% of BW
- 100% of BW
- 200% of BW
- 300% of BW
- 500% of BW
What is the compression force on the patella during
- walking?
- Jogging?
- Stair climbing?
- Down a stair?
- 90 degree squat?
- Knee extension?
- Jumping?
- 0.5x BW
- 4x BW
- 2.4x BW
- 3.5x BW
- 7.5x BW
- 8x BW
- > 10x BW
