Knee (Mechanics) Flashcards
(16 cards)
What type of joint is the tibiofemoral joint?
Ginglymoid, or modified hinge joint with six (6) degrees of freedom
T or F
Anterior cruciate ligament is considered the main stabilizer of the knee.
F (PCL)
From _______ of WB knee extension (moving toward full knee extension), the lateral condyle of the femur, together with the lateral meniscus, become congruent, moving the axis of movement more laterally.
30 to 5 degrees
In the last 5 degrees of extension, rotation is the only movement accompanying extension. This rotation is referred to as _____ and is a characteristic motion in the normal knee, in which during terminal knee extension the tibia externally rotates relative to the femur.
“screw home” mechanism
This joint is susceptible to orthopedic injury because it is the least stable joint in the lower limb and forces that are multiple times body weight are applied rapidly through a wide ROM.
Patellofemoral joint
What are the primary static restraints for the PF joint?
Medial patellofemoral ligament, medial and lateral retinacula, and the contact on the patella with the lateral edge of the patellar groove.
What are the primary dynamic restraints of the PFJ?
Quadriceps muscle, particularly the VMO, and the extensor mechanism in general.
It is a measure of the tendency of the patella to move laterally when the quadriceps muscles are contracted.
Quadriceps angle (Q-angle)
T or F
The Q-angle increases with knee flexion.
F (extension)
What is the normal value of the Q-angle?
▪ 8-14 degrees for males
▪ 15-17 degrees for females
T or F
Some of the highest Q-angles are found in patients with a combination of genu valgus and proximal tibial torsion.
F (varus)
This is an assessment of the relationship between the patella and the tibial tuberosity, and is another measurement that has been used to evaluate and treat PFJ pathology and as a quantitative measurement of patellar alignment.
Alignment Angle (A-angle)
T or F
The Q-angle shows the relationship between the longitudinal axis of the patellar and the patella tendon or the patella’s orientation to the tibial tubercle.
F (A-angle)
An A-angle greater than _____ is often cited as a cause of patellar pathomechanics.
35 degrees
Give the 4 patella-femur contact loading factors.
A. Angle of knee flexion
B. Location of contact
C. Surface area of contact
D. PFJ reaction force
One proposed mechanism or abnormal patellar tracking.
… is an imbalance in the activity or tension of the medial and lateral restraints.
