joints Flashcards
optimal pore size for bone ingrowth
50-150 um
safe zone for acetabular screw placement
posterior-superior
what structures are at risk in the anterior-superior quadrant of the acetabulum?
external iliac artery and vein
what structures are at risk in the posterior-inferior quadrant of the acetabulum?
sciatic nerve, inferior gluteal nerve and vessels, internal pudendal nerve and vessels
what structures are at risk in the anterior-inferior quadrant of the acetabulum?
obturator nerve, artery, vein
what vessel is between the TFL and sartorius in the anterior approach to the hip?
ascending branch of the lateral femoral circumflex
radiation dosing for HO ppx in THA
700-800 Gy within 24 hours before or 72 hours after surgery
ideal cup version
15-25 anteversion
goal combined anteversion
25-45
goal cup inclination
30-50 abduction
particle number and size in metal on poly and metal on metal
smaller particles in metal on metal but higher number
cell type in metal on metal wear debris
T-cell lymphocyte
what property causes fracture of ceramic heads
low toughness of material
properties of highly cross linked PE vs non-highly cross linked PE
highly cross linked generates smaller particles, is more resistant to wear, has reduced mechanical properties
order of release of medial structures in TKA
osteophytes, deep MCL (includes capsule), posterior medial corner (capsule, semimembranosus), superficial MCL
what part of the MCL is tight in flexion?
anterior superficial MCL
what part of the MCL is tight in extension?
posterior oblique superficial MCL
what can be damaged when you place a retractor inferior to the TAL?
obturator nerve and artery
structure at risk during lateral retinacular release in TKA
lateral superior geniculate artery
where is the MFCA at risk in a THA?
underneath the quadratus femoris muscle or glut max tendon
vessel at risk with placing retractor over ASIS in posterolateral approach for THA
branch of femoral artery
position of fusion for hip
20-25 flexion, neutral abduction, 0-30 external rotation
most common reason to convert hip fusion to THA
low back pain
best indication for constrained liner
abductor deficiency
gap size required for ingrowth
<50 um
what is the max amount of micromotion that allows ingrowth/ongrowth
<150 um
what nerve is most at risk with lengthening during THA
peroneal division of sciatic
why do ceramic bearings have high fracture risk
low toughness of material
cytokines a/w ALTR in MOM hips
IL-2/6, IFNy, RANKL
order of release for valgus knee
osteophytes, lateral capsule, IT band (tight in extension), popliteus (tight in flexion), LCL
common femoral deformity in valgus knee
lateral femoral condyle hypoplasia
how does lateral femoral condyle hypoplasia affect component position in TKA
internal rotation of femoral component/external rotation of tibial component
what kerboul angle is at high risk for collapse in AVN?
> 240, <190 is low risk
most important type of wear in osteolysis process
adhesive wear
cytokines release by macrophage in osteolysis
TNFa, IL-1B, TGFB, IL-6, PDGF, RANKL
main determinant of number of PE particles generated
volumetric wear (related to square of radius of the head)
how does head size affect linear and volumetric wear?
smaller head size -> increased linear wear, bigger head size -> increased volumetric wear
where is the ascending branch of the LFCA at risk in THA?
anterior approach. passes up between TFL and sartorius
what type of PE manufacturing has the best wear?
direct compression molding
what causes stripe wear?
repetitive subclinical subluxation
