Knee Flashcards
inflammation where the patellar tendon attaches to tibial tuberosity
Osgood Schlatter’s
___ distribute wt from ___ femoral condyles to tibial plateau
menisci
convex
compared to the lateral ones the medial plateau is more ___ and the medial meniscus is ___
concave
fixed (lateral is more mobile)
knee pivots on ___ compartment through flexion (tibial __ rotates) and extension (tibial __ rotates) => ___ meniscus under more shear stress
medial
internally
externally
medial
MCL resists ___ stress
rupture => __ instability
valgus x2
LCL resists ___ stress
varus
ACL resists ___ of the tibia and __ of the tibia in extension
anterior subluxation
internal rotation
PCL resists ___ of the tibia/ __ of femur and knee ___
rupture => __+___
posterior subluxation of tibia anterior subluxation of femur knee hyperextension => recurrent hyperextension instability descending stairs
posterolateral corner = +++ that resist ___ of tibia in flexion
rupture => + instability
LCL PCL popliteus and other ligs external rotation varus and rotatory
in younger ptnts meniscal tears usually caused by __/__
sport / rising from squat
in elderly ptnts meniscal tears are usually caused by __
atraumatic degenerative tears
__% of ACL ruptures have a meniscal tear
50
menisci that is 10x more likely than the other to tear
medial
Ix for meniscal tears
MRI
___ in knee menisci have blood supply therefore __ tears wont heal
peripheral 1/3
radial
appearance of a normal knee menisci on MRI
uniformly black
acute locked knee =
displaced bucket handle meniscal tear
in a displaced bucket handle meniscal tear patient will have a ___ block to extension
15 degree springy
Rx of displaced bucket handle meniscal tear =
if not within a few wks =>
Sx - arthroscopic repair / partial menisectomy
fixed flexion deformity
Grd 1 ligament injury =
tear some fibres but macroscopically intact = a sprain
Grd 2 ligament injury =
partial tear - some fascicles disrupted
Grd 3 ligament injury =
complete tear
Rx of MCL injury =
brace, early motion, physio
rarely needs Sx - advancement/reconstruction
how is MCL injured ?
severe valgus stress
how is ACL injured?
twisting
__% of ACL rupture ptnts have reconstruction
40%
Sx for ACL rupture if:
to protect meniscal repair to return to professional sport/ high demand job young multiligament reconstruction DOESNT treat pain/prevent arthritis
mechanism of LCL injury =
varus and hyperextension
if LCL injury doesnt heal there is a high incidence of ___
common peroneal nerve injury
usually LCL is injured along with __+__
PCL and ACL
complete rupture of LCL needs __ in <=2-3wks and then later ___
repair
reconstruction
mechanism of PCL injury =
direct blow to anterior tibia
hyperextension
isolated PCL rupture is __ and doesnt need __
get ____ pain and bruising
rare
reconstruction
popliteal
complications of knee dislocation =
popliteal artery injury
common peroneal nerve injury
compartment syndrome
Rx of knee dislocation
emergency reduction
recheck neurovascular supply
perhaps externally fix temporarily and multiligament reconstruction
mechanism of patellar dislocation
rapid turn/direct blow
risk factors for patellar dislocation (5)
F, adolescents, ligament laxity, valgus knee, torsional abnormalities
mechanism of extensor mechanism rupture =
fall on flexed knee with quads contracted => patellar/quad tendon rupture
predisposing factors to extensor mechanism rupture =
previous tendonitis
steroids
renal failure
ciprofloxacin
if in Extensor mechanism rupture there is no __ and a palpable __ => Sx repair
straight leg raise
gap
dashboard injury to knee =
PCL rupture
pain on joint line =
meniscal/chondral pathology
___ cartilage covers bone in synovial joint
hyaline
provides tensile strength to hyaline cartilage
collagen
provide compressible strength to hyaline cartilage
as they are highly ___
proteoglycans
hydrophilic
proteoglycans = ____ attaching __ branches with keratin sulfate and ____ chains
hyaluronic acid
protein
chondroitin sulfate
hyaline cartilage:
only ___ thickness can heal
heals with ___ which has more friction and less wear resistance
full
fibrocartilage
osteochondritis dissecans affects ____
age group=
most common site =
subchondral bone
adolescents
medial femoral condyle
area of knee surface loses blood supply and cartilage +/- bone fragments off -
osteochondritis dissecans
osteochondritis dissecans can heal spontaneouslybut is unlikely to heal after __
puberty
Rx of osteochondritis dissecans
if detaching on MRI = pin in place
if detached = fix/remove
if severe may = cartilage regeneration / micro# - better for smaller defects (not if OA/ inflam arth/joint instability)
cartilage regeneration is unsuccessful in ___ joint
patellofemoral
Rx for varus knee with isolated early medial compartment OA
osteotomy - shifts load to lateral compartment
affedcts result of later TKR ; good for heavy manual workers
