Knee Flashcards
how many articulating surfaces in the knee
3
how many distinct joints?
2
how many joint capsules
1
what are the two joints called
patellofemoral and tibiofemoral
what should be done at every visit
observation
what types of swelling occur at the knee
localized and generalized
localized swelling indicates
bursal
generalized swelling indicates
intra-articular (synovitis)
what test can be used for generalized swelling (synovitis) of the knee
bounce home
tibia has a slight varus/valgus angulation in comparison to the femur?
valgus
bowlegged
genu varus
knock knee
genu valgus
hyperextension of the knee
genu recurvatum
genu recurvatum more popular in what gender
females
people who have lax or long ligaments tend to have
genu recurvatum
if person has long ligament the recurvatum will be present
in elbow as well
two types of lax ligaments
acquired (gymnast) and gen isolated (golfer)
tibiofemoral joint is made up of
distal end of femur and proximal end of tibia
what separates the two femoral condyles
intercondylar eminece
what type of joint is the knee
ginglymoid (modified hinge joint)
the knee joint is complex and geometrically incongruous this lends
little inherent stability to the joint
knee joint stability is dependent on
static restraints f jt capsule
ligaments
menisci
dynamic restraints of quads/ hamstrings/ gastroc
where do the femoral condyles project
posteriorly from femoral shaft
largest bone in the body
femur
intercondylar eminences are attachment points for
ACL and PCL
which condyle is smaller
Lateral
why is the lateral condyle smaller?
less weight and downward foce
why is the medial condyle larger
it bears the main amount of the body weight
lateral condyle is ____shaped and faces ______
ball shaped and outward
what shape is the medial condyle and where does it face
elliptical faces in
what originates on the lateral condyle
popliteus
what originates on the posterior lateral epicondyle
lateral head of gastrocnemius and LCL
what originates on the medial epicondyle
insertion of adductor magnus, medial head of gastroc, and MCL
anterior-posterior width medial femoral condyle
bigger than lateral by about 1.7cm
articular surface of the medial femoral condyle
longer than lateral
proximal tibia has what
two plateaus
what separates the plateaus
intercondylar eminence
tibial plateaus are concave in what direction
medial to lateral
anterior posterior direction medial tibial plateau is
concave
anterior posterior direction lateral tibial plateau is
convex
the convexity of lateral plateau produces
more asymmetry and increase in lateral mobility
how much more surface area is there in medial plateau
50%
how much thicker is the articular surface of medial side
3x
what attaches to these plateaus
meniscus
patello femoral joint complex articulation dependant of what types of restraints for function
dynamic and static
posterior surface of the patella include how many facets
up to 7 (11)
what type of bone is the patella
sesmoid
what side of the knee is more prone to injury
medial
where is the patella embeded
in the tendon of quadriceps femoris superiorly and patella tendon inferiorly
in flexion patella fixed or mobile
fixed
in extension patella fixed or mobile
mobile
some basic functions of patella
articulation low friction
protect distal femur and quads from attritional wear
improve cosmetic appearance of the knee
improve moment arm of quads
decrease anterior-posterior tibiofemoral shear stress on knee
Q angle
bisection of two line
1-ASIS>patella
2- patella>tibial tubercle
most common Q angle range for women
15-17
most common Q angle range for men
8-14
any angle greater than 20 degrees
abnormal
and increased Q angle can be called
bayonet sign
patellofemoral athralgia
when knee flexed at 30 degrees tibia fails to derotate normally- patella tendon fails to line up with anterior crest of tibia
sup/inf>flex/ext patella moves
5-7cm
if the patella tracks abnormally
muscular imbalance
the bad tracking and imbalance is probably because of
VMO and vastis lateralis
normal patellar posture for exerting deceleration forces in a functional 45 degrees patella should be
squarely against anterior femur
if patella is lower than normal
patella baja
if patella is higher than normal
patella alto
what in the largest synovial capsule in the body
knee
the synovial memb is strange why
it excludes cruciate ligaments but is within the jt capsule
cruciate ligaments are considered
extrasynovial but intra articular
repetitive micro trauma on the knee causing traction apophysitis at the tibial tuberosity.
with or without avulsion
Osgood-Schlatter’s
Osgood-Schlatter’s is most common
preadolescent during growth spurt
predisposing factors for Osgood-Schlatter’s
tight hamstrings
tight achilles
tight quads
Osgood-Schlatter’s is more common in what gender
males
what ages does Osgood-Schlatter’s effect
10-15
when is pain with Osgood-Schlatter’s most prominant
going up or down stairs
Osgood-Schlatter’s has a history
single violent injury or repetitive flexion-extension movement
what four major ligaments are important in static stability of the knee
ACL, PCL, MCL, LCL
Primary restraint of knee anterior translation
ACL
Primary restraint of knee posterior translation
PCL
Primary restraint of knee valgus rotation
MCL
Primary restraint of knee varus rotation
LCL
Primary restraint of knee lateral rotation
MCL, LCL
Primary restraint of knee medial rotation
ACL, PCL
cruciate ligaments restrict what type of motion
normal rather than abnormal
what is one of the most important ligaments to knee stability
ACL
is there a need to xray osgood schlaters
no
what is the treatment for osgood schlaters
conservative, stop activity, self limiting, anti inflammatories (food)
longer thinner cruciate ligament
ACL
shorter broader cruciate ligament
PCL
MOI or ACL rupture
sudden deceleration
abrupt change direction/speed/velocity
closed kinetic chain (foot on ground)
90-95% total restrain to posterior translation of tibia on femur
PCL
MOI for PCL tear
excessive hyperflexion
hyperextension
common injury causing PCL tear
dashboard injury
broad and fas shaped collateral ligament
Medial Collateral ligament
difficult portion of MCL to palpate
posterior taut in extension blend with capsule and medial border of meniscus
aka for MCL
tibial collateral lig
primary function of MCL
stabilizer of medial side knee against valgus forces
Primary function of the LCL
resist varus forces
aka for LCL
fibular collateral ligament
how does the LCL differ from the MCL
develops independently
remains free from joint capsule and lateral meniscus
what separates LCL from inner structures of the knee
popliteus tendon
secondary restrains of the knee
hamstrings quadriceps patellar lig oblique popliteal ligaments fabella structures in the posterior-lateral and posterior- medial corners of the knee
what type of cartilage are the menisci made up of?
fibrocartilage
medial meniscus is shaped how
like a C
larger thicker meniscis
medial
wider in what direction
posteriorly than anteriorly
rounder O-shaped meniscus
laterl
more mobile meniscus
lateral
which has two meniscofemoral ligaments attaching to it
lateral
tear occurs in line with the circumferential fibers of the meniscus
longitudinal tear
extra long longitudinal tear that has flapped up
buckethandle tear
bucket-handle tear may displace into the intercondylar notch, where it may cause true locking of the knee joint.
displaced bucket handle
innbebition
displace fluid
how does meniscus lubricate
imbibe via movement
generally at the junction of the posterior and middle thirds small flap tear occurs
parrot beak
extend from the inner free margin toward the periphery
radial tear
why are radial tears difficult
avascular, generally wont heal- most medial aspect
function of meniscus
load transmission shock absorption joint lubrication joint stability guide movement
meniscectomy reduces shock-absorbing capacity by
20%
triad of O’donoghue
terrible triad
unhappy triad
MCL, ACL, medial meniscus rupture
what do bursae do
reduce friction and cushion the movement of one body part over another
what are the main bursae of the knee
deep infrapatellar gastroc pes anserine prepatellar superficial infra patellar
prepatellar bursitis aka
housemaids knee
MOI prepatellar bursitis
overuse
kneeling while leaned forward
direct blow
clergyman’s knee
infrapatellar bursitis
swelling both sides of the patellar lig
kneeling leaned back on heels
borders of popliteal fossa
superior lateral- biceps femoris
superior medial- semitendinosus/membranosus
inferior- 2 heads of gastroc
what are within the borders of popliteal fossa
posterior tibial nerve, popliteal artery and nerve
escaped synovial fluid enclosed in a membrane sac protruding through the joint capsule of the knee
bakers cyst
bakers cysts cause what distally
pooling in the foot and ankle
bakers cysts are associated with
RA
baker cysts are considered
femoral tibial joint disorder
two tests used to confirm
bowstring and bounce home
pain in the region of the knee that feels like meniscal tear. when surgeons go looking it is a clear meniscus.
won’t find it unless you are looking for it
plica
synovial mesenchymal reminant
plica
major muscles that act on the knee
quads hamstrings gastroc popliteus hip adductors
lateral restraints of the patella
retinaculum
which retinaculum is torn more often
lateral
what tests can be done to ensure stability of the retiaculum
patellar apprehension test
extension lag (last 10 degrees) of the knee is because of
weak quads
knee extension comes with some amount of tibial rotation this is called
helfets helix
how can it be determined extension lag is weak quads
circumferential mensuration three inches up from patella. atrophy
how do you asses proper motion of the tibia at the knee
screw home method
two dots one on patella and one on tib tub
completely locking the knee causes
deficant venous return cause people to pass out
major vessels of the knee
femoral
popliteal
genicular
major nerves
saphenous N
common peroneal N- palpate at fib neck
tibial N
tests that relate to sciatic N issues
SLR Bragard buckling bowstring lasegue bechterew anterior innominate/mazion/ advancement sign toe walk
biceps femoris action at the knee
flexion and external rotation
bicep femoris nerve supply
sciatic
bicep femoris N root derivation
L5, S1-2
Semimembranosus nerve supply
sciatic
Semimembranosus N root derivation
L5, S2-2
semitendinosus N supply
sciatic
semitendinosus N root derivation
L5 S1-2
Gracilis action
knee flexion
gracilis N supply
obturator
gracilis N root derivation
L2-3
Sartorius action
flexion knee
sartorius N supply
femoral
sartorius N root derivation
L2-3
popliteus action
flexion knee
popliteus N supply
tibial
popliteus N root derivation
L4-5 S1
Gastroc action
flexion knee
gastroc N supply
tibial
gastroc N root derivation
S1-2
tensor fascia lata action
flexion and extension of knee
tensor fascia lata N supply
sup glute
tensor fascia lata N root derivation
L4-5
rectus femoris
vastus medialis
vastus intermedius N supply
vastus lateralis
femoral
rectus femoris
vastus medialis
vastus intermedius N root derivation
vastus lateralis
L2-4
acute phase of intervention
reduce pain swelling control inflammation regain ROM min muscle atrophy maintain fitness
functional phase intervention
full painless ROM
restore normal jt kinematics
improve muscle strength
restore normal force couple relationships
