Hardware

Question 1

Buttress Plate: uses

Answer 1

wall that acts as a bridge between larger fragments with intervening small fragments leaning against the plate

-Usually used for peri/intra-articular fractures at the end of long bones

—- Distal tibia/pilon fractures

Question 2

Buttress plate: forces prevented

Answer 2

Prevents shearing/bending forces

Question 3

What side of injury is Buttress plate placed

Answer 3

on the tension side of an injury

Question 4

Neutralization plate: fracture type used in

Answer 4

applied to fractures already reduced/compressed with lag screw placed outside of the plate

-Protects interfrag screw from torsional forces

Question 5

What type of screws are used in a neutralization plate

Answer 5

all concentric screws

Question 6

Compression plate: when used and MOA

Answer 6

• used when lag screw fixation not enough

- MOA: overbend the plate, tension device, screw insertion geometry

Question 7

Important points about Static compression plate (3)

Answer 7

• compression achieved at the fracture
• Eccentric drilling of first two screws
• Rest of screws con be inserted concentrically

Question 8

Important points about dynamic compression plate (2)

Answer 8

-Compression achieved at fracture and when implant is subject to physiological loads

• Follows concept of tension band fixation
• —plate is placed on tension side not compression side

Question 9

What is a bridging plate

Answer 9

a neutralization plate without interfrag screws

Question 10

Bridging plate: what does it achieve

Answer 10

maintains length and alignment of severely comminuted fractures

Question 11

Wave plate: when is it used

Answer 11

for areas of delayed healing

-contoured away to allow bone graft and better ingrowth of vessels

Question 12

What is a Hook plate and when is it used

Answer 12

could be fashioned from 1/3 tubular plate

used for small/comminuted medial malleolar fragments

Question 13

Limited contact plate: design

Answer 13

grooves present on the underside of the plate that limit periosteal contact

Question 14

Tension band: construct and when useful

Answer 14

• 2 parallel K-wires reverses tension and turns it into compression
• good for avulsion fracture, malleoli, small fragment, comminuted fracture

Question 15

Stainless steel wire: when useful

Answer 15

for IPJ fusion

Question 16

Stainless steel wire: pro’s and cons

Answer 16

Pro: osteoporotic bone, splintage

Con: no compression, tendons may become irritated

Question 17

Axial or dynamic compression: 3 different modifications

Answer 17

1) neutralization mode: centered
2) compression mode: 1 mm eccentrically away from fracture line
3) Buttress mode- 1 mm eccentrically towards fracture line

Question 18

Limited contact dynamic compression: construct and how is stress distributed

Answer 18

• Underside of plate contoured for compression in different directions
• better distribution of stress to plate, less hardware failure

Question 19

Locking plate: how is force distributed

Answer 19

• Evenly distributes force across entire screw

- Screw and plate function as one unit instead of separate units.

Question 20

Reconstruction plate: construct

Answer 20

notches allow for easier bending

Question 21

Cortical screw: anatomy

Answer 21

threads are closer together than cancellous screw for better cortical bon contact

Question 22

Cortical Screw: what does the core diameter affect

Answer 22

Large core diameter increases strength

Question 23

Shaft screw: anatomy and when used

Answer 23

• Partially treaded

- For interfrag compression

Question 24

Cancellous screw anatomy

Answer 24

Threads are further apart for better cancellous bone contact.

-When used as lag screw the entire length of the thread should be in fracture fragment

Question 25

Cancellous screw: threads

Answer 25

deep and widely spaced apart

Question 26

Cancellous screw: self tapping

Answer 26

yes

Question 27

Cancellous screw: used

Answer 27

as lag screws for metaphyseal fractures

Question 28

Cortical screws: threads

Answer 28

shallow and closely spaced

Question 29

Cortical screw: self tapping

Answer 29

NO

Question 30

Describe Malleolar screws

Answer 30

partially threaded self cutting cortical screw

Question 31

Describe Herbert screw

Answer 31

• Headless screw.
• proximal and distal threads are separated by smooth shaft
• Leading threads have greater pitch. Allow for some compression

Question 32

Lag screw: optimal screw placement

Answer 32

one screw perpendicular to long axis of bone and the rest perpendicular to fracture line

Question 33

Lag screw: perpendicular to fracture

Answer 33

max interfrag compression but minimal axial stability

Question 34

Lag screw: perpendicular to long axis of bone

Answer 34

max axial stability,can cause dislocation of fragments as it is tightened

Question 35

Drill bit sizes: mini frag set

Answer 35

1. 1 (U)—> 1.5 (O)
2. 5(U)—> 2.0 (O)
3. 0 (U)—> 2.7 (O)

Question 36

Drill bit sizes: small frag set

Answer 36

2. 5 (U)—> 3.5 (O)

2. 5 (U)—> 4.0 (O)

Question 37

Drill bit sizes: large frag size

Answer 37

3. 2 (U)—> 4.5 (O)

3. 2(U)—> 6.5 (O)

Question 38

Steps to AO screw fixation (6)

Answer 38

• Underdrill
• Overdrill
• Countersink
• Measure
• Tap
• Insert

Question 39

1st screw placed in Lapidus procedure

• size
• orientation

Answer 39

-3.5 screw or 4.0 screw

“home run screw”

-from dorsal Met to plantar medial medial cuneiform

Question 40

Size of screw for Lisfranc arthrodesis

Answer 40

3.5 or 4.0 screw

Question 41

Triple arthrodesis size of screw

Answer 41

6.5 or 7.0 cannulated screws