The Knee Complex Flashcards
Tibio Femoral Joint
1 DOF
ext/flx 0-135 deg
Rotary degree
tibiofemoral end feels
flx -soft
ext-firm
what defines the tibiofemoral double condyloid joint?
the medial and lateral articular surfaces
Femur
bicondylar, CONVEX
Q angle
normally 10-15 deg
as Q angle increases comprssion forces in the vastus lateralis will increase risk for lateral dislocation
forms a line connecting the ASIS to midpoint of patella, as well as midpoint of patella to tibial tuberosity
genu valgum
Increase in Q angle
compression laterally
genu varum
decrease in Q angle
compression medially
genu recurvatum
knee extension greater than 5 deg
can be due to muscle imbalances, systemic hypomobility, previous injury, nuerological deficit
What is the function of the cartilage support in the tibiofemoral joint ?
distribute the load
reduce friction between the tibia and the femur
medial meniscus
C shaped
lateral menisicus
4/5 of a circle
Surgeons “red zone”
external 1/3 recieves highly vascularized
surgical repair has high likelihood to heal
MCL
primary restraint to excessive valgus
is pulled taut in extension
given slack in flexion
LCL
primary restraint to excessive varus
attatches to fibular head
is pulled taut in extensions
slackened in flexion
ACL
primary restraint against anterior translation of tibia on the femur
taut in extenson
What muscle may resist anterior translation of the tibia?
Hamstrings
PCL
primary restraint to posterior displacement of the tibia on the femur
taut in flexion
IT Band
an extension of the TFL and gluteus maximus
function: passive lateral support to the knee
Patella
flat triangular shaped bone embedded with the quadriceps tendon
largest sesamoid in the body
function: an anatomical pulley for the quadriceps muscle
What motions can the patella do?
medial and lateral shift
media and lateral tilt
medial and lateral rotation
full extension
only the inferior pole of the patella makes contact with the femur
20 deg
patella and femur relation during flexion
as flexion continues the contact area between the two moves superiorly and laterally
full flexion
only the lateral and odd facets are making contact with the femur
In open kinetic chain what is the kinematics of the tibiofemoral joint
concave on convex
In closed kinetic chain what is the kinematics of the tibiofemoral joint
convex on concave
closed chain flexion
posterior roll with anterior glide
closed chain extension
anterior roll with posterior glide
screw home mechanism
occurs in last 20-30 deg of knee extension
an integral rotation to achieve full knee extension for stability of the joint
Initiation of knee flexion
tibia IR
femur ER
Completing knee extension
tibia ER
femur IR
Medial rotators of the knee
politeus
semimembranous
semitendinous
sartorius
gracilis
lateral rotators of the knee
biceps femoris
Knee extenstors
rec fem crosses two joints
not all fibers are oriented in same direction
what is the function of the patella?
lengthens the moment arm of the quads to increase distance of quadriceps tendon and patellar tendon of the knee joint
when is peak torques of the knee observed?
45 to 60 deg of knee flexion
patellofemoral pain syndrome
most accurate test is to reproduce the symptoms of squatting
ex. stair climbing and kneeling
what are the 4 types of patellofemoral pain syndrome
- overuse
- PFP with muscle performance deficits
3.PFP with movement cord deficits
4.PFP with mobility deficits
Bursitis
a direct blow or prolonged compressive or tensile forces
chondromalacia patella
cartilaginous changes seen on lateral surface of patellar facet
debated to be the same as PFP
they say cartilage is aneural, thus damage may extend beyond that tissue articular cartilage
What does genu recurvatum cause
compensatory lumbar lordosis
What part of the meniscus heals best
outer
