Kinesiology of the knee Flashcards
Due to oblique axis, In full extension the tibia lies slightly _______ to the femur.
lateral
Due to oblique axis, In full flexion of the femur the tibia lies slightly ________ to the femur.
Medial
Both ___ & ___ are intracapsular and extrasynovial
ACL and PCL
O’Donahue’s triad
ACL, MCL, medial meniscus injury during valgus stress to a flexed knee.T
Tibiofemoral joint CPP
Full extension with external tibial rotation
Tibiofemoral joint capsular pattern
Flexion > extension
Tibiofemoral typical dislocation
Tibia moves anterior or posterior, uncommon
Axis of rotation at the knee is _______ in a superolateral direction
Oblique
This occurs as the medial femoral condyle is slightly longer than the lateral.
During terminal knee extension in non-weight bearing, the tibia rotates laterally about __ degrees on the fixed femur
20 degrees
_________ is primarily responsible for unlocking the femur and tibia.
Popliteus
_______ ________ and ___ are responsible for locking the tibia
Biceps femoris and ITB
Adductor magnus is responsible for locking the _______
Femur
This mechanism provides stability to the fully extended knee on standing so that the quadriceps activity is not required.
Locking-unlocking mechanism
The long axis of the femur and the long axis of the tibia intersect to create a physiologic valgus at the knee joint of ___-___ degrees
185-190 degrees
During terminal knee extension in weight bearing, the femur rotates _____ on the fixed tibia
Medially (internally)
_____________ allows us to stand erect for prolonged periods of time without requiring constant quadriceps contraction.
Screw home mechanism
In open kinetic chain the tibia must ________ rotate on fixed femur to unlock
Medially
In closed kinetic chain, the femur must ________ rotate on fixed tibia to unlock
Laterally
Medial/lateral rotation of the tibiofemoral joint occurs in what axis?
It occurs about mechanical axis of tibia roughly located at the medial tibial intercondylar tubercle
Rotation is maximal at ___ degrees knee flexion due to laxity in MCL and LCL
90 degrees
______ axis is directed inferomedial, whereas the ______ axis is directly vertical
Femoral axis
Tibial axis
-when these axes meet the form an “obtuse angle” of 185-190 degrees opening medially
Genu Varum
angle less than 175 degrees
Genu Valgum
Angle greater than 195 degrees
Genu recurvatum
Hyperextension of the knees in standing
May be BL or unilateral
Patellofemoral joint CPP
Full flexion; least congruent joint in the body
Patellofemoral joint capsular pattern
Not applicable
cartilage on posteromedial patella typically sees greatest degeneration
Patellofemoral joint typical dislocation
superolateral
The _______ acts to change the angle of pull of the quadriceps as a group
patella
___% increase in quadriceps force required to complete last ___ degrees of knee extension b/c this is the point at which the moment arm is the smallest
60% to complete last 15 degrees
As flexion increases, so does the force generated by ______ and thus compressive force across the PF joint
quadriceps mm
Contributing factors to lateral tracking of the patella
Stronger VL and VMO
lateral tibial torsion accompanying subtalar supination
Femoral retroversion
Hamstring group is significantly active in ________ chain movements
Closed chain
(to stabilise the pelvis during trunk motion)
2/3 as strong as quads- don’t work against gravity
Gastrocs primarily acts to prevent knee _________________ (by firing eccentrically)
hyperextension
Vastus _________ key in optimal patellar tracking
vastus __________ key in terminal extension
Vastus medialis oblique
Vastus medialis longus
