TKA THA

Question 1

DOF of knee

Answer 1

6 DOF

Question 2

varus

Answer 2

knee out

Question 3

valgus

Answer 3

knees in

Question 4

causes of knee degeneration

Answer 4

osteoarthritis
fractures
torn cartilage/ligaments

Question 5

more conforming implant

Answer 5

Higher stress across fixation surface
lower wear/stres on PE

Question 6

less conforming implant

Answer 6

lower stress across fixation surface
higher wear/stres on PE

Question 7

reduced radius

Answer 7

increasing radius near extension and decreasing radius at flexion

Question 8

single radius

Answer 8

identical femoral radius from extension to flexion

Question 9

advantages of UKA

Answer 9

preserves ACL
smaller incision and less blood loss
lesser bone removed
quicker recovery

Question 10

disadvantages of UKA

Answer 10

short life
loosening risk
prosthetic wear
degeneration of opposite compartment

Question 11

Causes for THA

Answer 11

arthritis
hip dysplasia
avascular necrosis
hip fracture

Question 12

arthritis / dysplasia

Answer 12

wear of cartilage
bone on bone contact
joint becomes stiff, uneven, painful

Question 13

avascular necrosis

Answer 13

disruption of blood supply to hip
bone tissues die and femoral head collapses

Question 14

intracapsular fracture

Answer 14

subcaptial neck fracture
transcervical neck frac
basicervical neck frac

Question 15

extracapsular fractures

Answer 15

trochanteric
subtrochanteric

Question 16

garden 1

Answer 16

incomplete fracture of the femoral neck

Question 17

garden 2

Answer 17

complete fracture without displacement

Question 18

garden 3

Answer 18

complete fracture with partial displacement

Question 19

garden 4

Answer 19

complete fracture with full displacement

Question 20

as the fracture angle increases there is a greater risk of a non union due to ….

Answer 20

increasing shear stresses across the fracture

Question 21

cannulated hip screws

Answer 21

multiple screws in parallel
used for un-displaced femoral neck fractures
good for fracture which no shear stress (horizontal)

Question 22

dynamic hip screws

Answer 22

-extra-capsular fractures
-adequate for fracture with shear stress
-resist angular deformation while allowing compression along the lag screws axis
l-ag screw is inserted into the head of the femur and held in place by a plate positioned on the side of the femur

Question 23

Cephalo-medullary device

Answer 23

• intramedullary nails designed for the fixation of the femoral head and neck
• complex proximal femoral fractures
• nail is closer to the central axis of the femur
  -act as load sharing device

Question 24

hemiarthroplasty hip

Answer 24

-replaces one half of the joint
-recommended only for elderly due to their low life span
- tends to loosen or to erode acetabulum

Question 25

THA components

Answer 25

femoral head
femoral stem
acetabular cup
polyethylene between liner and ball

Question 26

THR

Answer 26

resurfacing
preserves more bone
removes cartilage and damaged tissues
places a metal cap and cup over the femoral hear and acetabulum
small stem

Question 27

THR advantages

Answer 27

head size is more natural to fem head
less wear due to advanced bearing
bone conservation

Question 28

stability is sustained by…

Answer 28

bony impingement, muscle and ligaments tension force

Question 29

hip implant design considerations

Answer 29

ROM
stability
wear resistance
lifestyle
gender
age
weight
severity of wear

Question 30

Metal on poly - pros/cons

Answer 30

pros:
options
toughness
cons:
wear of standard poly
xlpe sensitivity

Question 31

cer on poly - pros /cons

Answer 31

pros:
reduced wear
abrasion resistance
cons:
fracture risks
fewer sizes

Question 32

metal on metal - pros /cons

Answer 32

pros:
reduced wear
head size options
strength and toughness
cons:
high ion levels
sensitive to abrasion