joints

Question 1

optimal pore size for bone ingrowth

Answer 1

50-150 um

Question 2

safe zone for acetabular screw placement

Answer 2

posterior-superior

Question 3

what structures are at risk in the anterior-superior quadrant of the acetabulum?

Answer 3

external iliac artery and vein

Question 4

what structures are at risk in the posterior-inferior quadrant of the acetabulum?

Answer 4

sciatic nerve, inferior gluteal nerve and vessels, internal pudendal nerve and vessels

Question 5

what structures are at risk in the anterior-inferior quadrant of the acetabulum?

Answer 5

obturator nerve, artery, vein

Question 6

what vessel is between the TFL and sartorius in the anterior approach to the hip?

Answer 6

ascending branch of the lateral femoral circumflex

Question 7

radiation dosing for HO ppx in THA

Answer 7

700-800 Gy within 24 hours before or 72 hours after surgery

Question 8

ideal cup version

Answer 8

15-25 anteversion

Question 9

goal combined anteversion

Answer 9

25-45

Question 10

goal cup inclination

Answer 10

30-50 abduction

Question 11

particle number and size in metal on poly and metal on metal

Answer 11

smaller particles in metal on metal but higher number

Question 12

cell type in metal on metal wear debris

Answer 12

T-cell lymphocyte

Question 13

what property causes fracture of ceramic heads

Answer 13

low toughness of material

Question 14

properties of highly cross linked PE vs non-highly cross linked PE

Answer 14

highly cross linked generates smaller particles, is more resistant to wear, has reduced mechanical properties

Question 15

order of release of medial structures in TKA

Answer 15

osteophytes, deep MCL (includes capsule), posterior medial corner (capsule, semimembranosus), superficial MCL

Question 16

what part of the MCL is tight in flexion?

Answer 16

anterior superficial MCL

Question 17

what part of the MCL is tight in extension?

Answer 17

posterior oblique superficial MCL

Question 18

what can be damaged when you place a retractor inferior to the TAL?

Answer 18

obturator nerve and artery

Question 19

structure at risk during lateral retinacular release in TKA

Answer 19

lateral superior geniculate artery

Question 20

where is the MFCA at risk in a THA?

Answer 20

underneath the quadratus femoris muscle or glut max tendon

Question 21

vessel at risk with placing retractor over ASIS in posterolateral approach for THA

Answer 21

branch of femoral artery

Question 22

position of fusion for hip

Answer 22

20-25 flexion, neutral abduction, 0-30 external rotation

Question 23

most common reason to convert hip fusion to THA

Answer 23

low back pain

Question 24

best indication for constrained liner

Answer 24

abductor deficiency

Question 25

gap size required for ingrowth

Answer 25

<50 um

Question 26

what is the max amount of micromotion that allows ingrowth/ongrowth

Answer 26

<150 um

Question 27

what nerve is most at risk with lengthening during THA

Answer 27

peroneal division of sciatic

Question 28

why do ceramic bearings have high fracture risk

Answer 28

low toughness of material

Question 29

cytokines a/w ALTR in MOM hips

Answer 29

IL-2/6, IFNy, RANKL

Question 30

order of release for valgus knee

Answer 30

osteophytes, lateral capsule, IT band (tight in extension), popliteus (tight in flexion), LCL

Question 31

common femoral deformity in valgus knee

Answer 31

lateral femoral condyle hypoplasia

Question 32

how does lateral femoral condyle hypoplasia affect component position in TKA

Answer 32

internal rotation of femoral component/external rotation of tibial component

Question 33

what kerboul angle is at high risk for collapse in AVN?

Answer 33

>240, <190 is low risk

Question 34

most important type of wear in osteolysis process

Answer 34

adhesive wear

Question 35

cytokines release by macrophage in osteolysis

Answer 35

TNFa, IL-1B, TGFB, IL-6, PDGF, RANKL

Question 36

main determinant of number of PE particles generated

Answer 36

volumetric wear (related to square of radius of the head)

Question 37

how does head size affect linear and volumetric wear?

Answer 37

smaller head size -> increased linear wear, bigger head size -> increased volumetric wear

Question 38

where is the ascending branch of the LFCA at risk in THA?

Answer 38

anterior approach. passes up between TFL and sartorius

Question 39

what type of PE manufacturing has the best wear?

Answer 39

direct compression molding

Question 40

what causes stripe wear?

Answer 40

repetitive subclinical subluxation