Knee Flashcards
How much knee flexion is required for level surface gait?
60-68°
How much knee flexion is required for stairs?
80 ascending, 90 descending
How much knee flexion is required for sit-stand-sit transfers?
90*
how much knee flexion is required for tying a shoe?
106
How much knee flexion is required for full squat to floor?
150-160
What is the roll & slide for OKC knee extension?
anterior & anterior
What is the roll & slide for OKC knee flexion ?
Posterior & Posterior
What direction does the menisci translate in OKC extension?
Anterior
why does the menisci translate forward in OKC extension?
Meniscopatellar ligaments
What direction does the menisci translate in OKC flexion?
Posterior
Why does the meniscus translate back in OKC flexion?
Semimembranous attach to medial meniscus
Popliteus attachment to lateral meniscus
What is the function of menisci?
- Increase tibial plateau radius of curvature
- Reduce TF friction
- Attenuated TF compression loads
- TF total contact area
In CKC flexion what is the roll & glide?
Posterior roll & anterior slide
By 15° of flexion in CKC what is occurring?
Medial compartment posterior roll begins to be accompanied by small amount of anterior slide
why does movement begin first in the medial compartment?
Medial femoral condyle has more surface are so it has more work to do
What occurs at 25° of flexion in CKC?
Lateral compartment posterior roll begins to be accompanied by small amount of anterior slide
What occurs by mid ROM in CKC flexion?
Equal magnitude of posterior roll & anterior femoral slide within both compartments
By late ROM what occurs in CKC flexion?
Larger amount of anterior femoral slide than posterior femoral roll in both compartments
By end ROM what occurs in CKC knee flexion?
All anterior femoral slide in both compartment
when is the angle of inclination for the ACL the smallest?
full flexion
what does the ACL control in CKC knee flexion when coming from terminal extension?
Posterior femoral roll
In deeper degrees of CKC knee flexion what does the ACL control?
sufficient enough to produce femoral slide
what is the impact of hyperextension on the ACL?
Middle of ACL comes in contact w/ femoral intercondylar shelf (notch of grant) which tension loads ACL causing disruptions in the middle of ACL
what bands of the ACL are taut in greater degree of flexion?
Anteromedial (AMB)
what bands of the ACL are tart in greater degree of extension?
Posterolateral (PLB)
T or F: Some portion of the ACL is taut in all varying degrees of TF movement
True
When does greatest movement of tibia anteriorly occur?
about 30° b/c neither band is really streteched
When is the angle of inclination smallest for the PCL?
full extension
What occurs because of the PCL in greater degrees of extension?
Posterior directed force is sufficient enough to produce posterior femoral slide
What is the ligamentous check rein to internal rotation?
Cruciates
what is the ligamentous check rein to external rotation?
Collateral
what is the screw home mechanism?
Automatic, conjunct, obligatory ER of tibia w/ terminal 20-30 degrees of knee extension
What do the cruciate do during the screw home mechanism?
Wind around each other as reach extension
what does an increase in valgus result in?
- Compression overload to lateral TF compartment
- Distraction overload to medial TF compartment
what does a decrease in valgus result in?
- Compression overload to medial TF compartment
- Distraction overload to lateral TF compartment
In the frontal plane slight valgus occurs with?
IR
In frontal plane slight Varus occurs with?
ER
What is the degrees of the posterior tibial slope?
9
in ER which is compartment is lengthened and what does this produce?
Lateral is lengthened, so medial is shortened producing TF varus
In IR which compartment is lengthened & what does this produce?
Lentehed medial, so lateral is shortened producing TF valgus
Why is the patella so important in function of the quads?
- Patella contributes to quads MA
- No angle w/o patella & therefore no compressive resultant force
What is the function of PF compressive force>
Stabilize patella in trochlea groove
Patella assures some compression in full extension
why does the patella not have much stability?
Patella not in femoral sulcus
TRUE or FALSE: PFC force increase with increase flexion
True
True or False: There is not a consistent PF compressive load from extension to flexion b/c of the patella tilting
true
What’s the order of facet of the patella making contact?
Infrafacet
Middle
Superior
Then odd
Around what degree of flexion does the odd facet (medial) make contact?
120°
what is the IT band impact on the patella?
Add an additional tendency for lateral translation
What is the result of Quad Q angle?
Tendency to laterally translate the patealla
What are 3 way to increase the Q-Angle?
- Laterally displace tibial tubercle
- Medially displace patella
- Laterally displace ASIS
