Knee Flashcards
why is the knee subjected to very large moments?
connects the longest two levers in the body; has powerful musculature
arthrokinematic motion of knee flexion? (closed chain)
posterior roll, anterior glide
w/ lateral rotation
what are the functions of the menisci?
primary function of menisci?
shock absorption,
lubrication,
decreases joint stress
stabilization
increase the tibiofemoral contact area
what is compressed during genu varum?
medial mensicus
what is compressed during genu valgum?
lateral meniscus
what does the medial meniscus attach to?
MCL, ACL, PCL, and semimebranosus
what does the lateral meniscus attach to?
ACL, Meniscofemoral ligament, popliteus
which direction does the meniscus move during flexion?
which direction does the meniscus move during extension?
posterior
anterior
What is the normal femoro-tibial joitn alignment?
5-10 degrees of valgus
what is the normal gait pattern during walking for knee flexion?
65-75 degrees of knee flexion
what is the normal gait pattern during climbing stairs for knee flexion?
90-110 degrees of knee flexion
what is the primary factor that affects knee rotation?
sagittal plane position
what is the extensor retinaculum composed of?
medial patellofemoral ligament and lateral patellofemoral ligament; quadriceps muscle
what is the posterior capsule composed of?
oblique popliteal ligament, posterior oblique, arcuate ligament
what two ligaments attach to the popliteus?
oblique popliteal ligament and arcuate ligament
when are the MCL and LCL taught?
in extension
which ligament protects from anterior sheer force?
MCL
what two structures protect from a varus stress?
popliteus, ITB
what compartment does loading occur in for varus stress?
medial compartment
what does the ACL protect from?
anterior glide of tibia, excessive extension
when is the anteromedial bundle more taught?
flexion & tibial medial rotation
when is the posterolateral bundle more taught?
extension
which ligaments resist rotary forces?
all
which ligaments resist anterior and posterior glide?
ACL, PCL, MCL, LCL
static loading on the FTJ is affected by?
malalignment (varus or valgus); obesity
what kind of moment does gait cause at the FTJ?
adduction
what is the primary function of the patella?
to increase MA of quads
how much pull is on the rectus femoris, vastus lateralis, and vastus intermedius?
35 degree lateral pull
how much pull does the vastus medialis have?
40 degree medial pull
what is the quad resultant pull?
7-10 degrees laterally
what are the primary motions of the patella during knee flexion?
inferior glide, medial and lateral translation until 30-45 degrees, lateral tilt, patellar flexion
what is the closed pack position of the patella?
flexion
when does the contact area of the patella increase as the knee flexes?
at 90 degrees
what is the function of the popliteus?
unlocks the knee by medially rotating the tibia
what does the hamstring muscle group resist?
varus and valgus forces, resists anterior glide
what is the function of pes anserinus?
medial rotation, flexion, and resists valgus force and lateral rotation forces
what is the function of the TFL?
extension, lateral rotation, and resists varus force
when is length tension the greatest for the knee extensors?
higher force towards flexion if the hip is flexed
During a closed kinematic chain exercise (squat), when is moment arm the greatest?
in knee flexion
as knee flexion moment increases, this increases _______ force.
knee extension force
when is there an increased PFJ loading?
during quad contraction and knee flexion
glut med weakness causes what?
increase in femoral IR, femur tracks under patella
if you have foot pronated, what happens to the tibia?
internally rotates
what are the most effective treatments for patellofemoral problems?
hip external rotation strengthening, knee extensor strengthening, quads, glutes, hip flexors and extensors
arthrokinematic motion of open chain knee extension.
anterior roll, anterior glide, lateral rotation
arthrokinematic motion of closed chain knee extension.
anterior roll, posterior glide, medial rotation
arthrokinematic motion of open chain knee flexion.
posterior roll, posterior glide
when does the suprapatellar pouch slide downward?
during knee flexion
what is genu recurvatum known as?
hyperextension
what causes an increase in the Q angle?
lateral tibial torsion
what occurs at the knee with an increase in Q angle?
anterior knee pain
dynamic loading at the FTJ is affected by what?
3x body weight and gait causing an adduction moment at the FTJ resulting in compression in medial compartment
which type of tracking is associated with PFJ pain?
lateral tracking
what is the downside of having knee musculature?
increases the compressive loads
in open chain, when is there maximal JRF?
midrange
in closed chain, when is there maximal JRF?
90 degrees
