Knee Flashcards
What is the primary function of the proximal tibia?
Transfers weight across the knee to the ankle
True or False:
The fibula has no direct function at the knee.
True
The base of the patella is (superior/inferior) to the apex.
Superior
What is the normal Q angle of the knee?
13-15 degrees
What is the excessive frontal plane deviation with a knee angle measurement of less than or about 165 degrees?
Excessive genu valgum (knock-kneed)
What is the excessive frontal plane deviation with a knee angle measurement of more than or about 180 degrees?
Gene varum (bow-legged)
What is the natural frontal plane deviation in most people?
Genu valgum
A valgus force is applied ____, pushing in the ____ direction and the ____ collateral ligament would be stretched taut.
Laterally; medial; MCL
A varus force is applied ____, pushing in the ____ direction and the ____ collateral ligament would be stretched taut.
Medially; lateral; LCL
What shape is the medial meniscus?
Oval
What shape is the lateral meniscus?
Circular
What are the functions of the menisci?
- Reduce compressive stress
- Stabilization of the joint during motion
- Lubricating articular cartilage
- Providing proprioception
- Help guide knee arthrokinematics
Medial meniscus tears usually involve what components?
- axial rotation (forceful rotation of the femur over a partially flexed weight bearing knee)
- external values force
What is the ROM for the tibiofemoral joint?
140 - 0 - 5
In open chain knee extension the tibia rolled anterior, slides ____ and spins _____ on the femur
Anteriorly; externally
In close chain knee extension, the femur rolls anterior, slides _____, and spins_____ on the tibia
Posteriorly; internally
In closed chain extension, the PCL causes the _________ of femur while the condyles roll anteriorly.
Posterior slide
The axis of rotation at the knee has a tendency to migrate _____ as you go into more flexion.
Posteriorly
During _____ rotation of the tibia, the cruciate ligaments are twisted around each other. This occurs during (flexion/extension).
Internal; flexion
During _____ rotation of the tibia, the cruciate ligaments almost separate from each other. This happens during (flexion/extension).
External; extension
True or false:
The LCL is more taut in flexion and more slack in extension.
False; more slack in flexion and more taut in extension
The ACL limits (anterior/posterior) translation of the femur relative to the fixed lower leg.
Posterior
If the tibia was shoved anteriorly, what ligament would block the motion?
ACL
What are the most common mechanism of ACL injury?
- Strong activation of quads over slightly flexed or fully extended knee
- Valgus collapse of knee
- Excessive ER of knee
(other mechanisms: excessive IR combined with extension and extreme valgus; excessive hyperextension of knee while foot is firmly planted)
The PCL limits (anterior/posterior) translation of the tibia relative to the femur.
Posterior
When is the PCL most taut?
knee flexion
What are the most common mechanisms of PCL injury?
- Falling over a flexed knee where the proximal tibia hits the ground
- “dashboard injury”
PCL injuries are associated with high energy trauma
What is the normal frontal plane angle of the knee?
170-175
Hyperextension of the knee beyond 10 degrees of neutral
Genu Rectavatum
What happens when the Q angle increases?
A larger lateral bow string force occurs and pulls the patella laterally over a region of reduced contact area
