tx tight in extension (unable to achieve full extension), balanced flexion
cut more distal femur
cut off for aspirate TKA
WBC more than 1100
PMN more than 64%
cut off for aspirate THA
WBC more than 3000
PMN more than
cam mech
in PS knee
post built into poly that articulates w fem component in flexion
loose flexion gap in PS knee causes
posterior knee dislocation when cam jumps the post in flexion
osteolysis cellular mech
macrophage activation and bone resorption (lytic lesion on XR)
ideal size of cement mantle
at least 2 mm
contraindication for constrained acetab liner
malpositioned implant
young pt w large inherent ROM
if pt had prior patellectomy what type of TKA
posterior stabilized TKA
if fem component has a box then it is
Posterior stabilied
indications for constrained acetab components
1) abd insufficiency/capsular attenuation
2) neuro dz
3) well positioned comp
WAYS to incr hip dislocation
head neck ratio
decr head neck ratio
WAYS to decr hip dislocation
skirted femoral head
incr dislocation bc decr head neck ratio
osteolysis is due to macrophage response to wear particles of what size
less than 1 micron in size
indications for constrained nonhinged TKA
varus/valgus deformity w MCL/LCL incompetency
post polio
neuorpathic arthropathy
how to measure femoral offset
distance from center fem head to line down fem shaft
how to decr osteolysis around distal fem stem
use proximally circumferentially coated ingrowth stem
indications for constrained acetab component
recurrent dx due to
- capsular attenuation
- abductor dysfunction
- cog dz
- late dx w well positioned components
if tight in both flexion/extension do what
resect more prox tibia
high or low osteolysis with alumnia ceramic
low
mc reason for reoperation in 1st 6 months after hip resurfacing
fem neck fx
release of popliteus does what in valgus knee
increase lateral flexion space
how to decr Q angle and patellar subluxation
ER fem/tibial component
moving fem head medially will incr or decr offset
incr
