Unit 6B - Surgical Fracture Fixation

Question 1

What is the most commonly used material in fracture fixation?

Answer 1

Stainless steel

Question 2

What are the 3 parts of a screw?

Answer 2

Head
Shaft
Tip

Question 3

What 3 factors determine the strength of a screw fixation?

Answer 3

1. Strength of screw
2. Strength of bone
3. Design of screw thread

Question 4

What are the functions of the head of a screw?

Answer 4

1. Provides a butters to stop the hold screw sinking into the bone
2. Provides a connection with the screwdriver

Question 5

Name 3 type sof screw head shapes?

Answer 5

1. Hexagonal
2. Crosshead
3. Star

Question 6

Name the 3 different screw diameters to consider?

Answer 6

1. Core diameter
2. Shaft diameter
3. Thread diameter

Question 7

What is the pitch of a screw?

Answer 7

The linear distance travelled by the screw for a compete turn of the screw

Question 8

Why are cortical screws not self-tapping?

Answer 8

Self tapping would cause damage to the bone and make screw impossible to insert due to excessive torque required

Question 9

In engineering process of compressing two objects together is sometimes called what?

Answer 9

Lagging

Question 10

Name 5 applications of orthopaedic screws?

Answer 10

1. To prevent sideways displacement of fragments
2. To hold a plate against bone
3. To increase the grip of an intramedullary nail one the bone
4. To permit displacement in an axial direction
5. As part of an external fixator assembly

Question 11

What is osteosynthesis?

Answer 11

Reconstruction of a fractured bone by surgical and mechanical means

Question 12

When is the use of plates indicated?

Answer 12

1. When anatomical alignment must be restored accurately
2. Where the use of screws alone is inadequate
3. When load sharing may be achieved with confidence

Question 13

Name 4 areas of the body where plates are commonly used?

Answer 13

1. Around joints
2. In bones of the forearm
3. On the pelvis
4. On the face and jaw

Question 14

What is the primary function of K-wires?

Answer 14

To maintain fragments in alignment by pushing them or holding them together

Question 15

Flexible wire is used to induce compression in which 2 ways?

Answer 15

1. Used statically by enclosing or crossing the fragments (clerage)
2. Used dynamically as a tension band

Question 16

Why is wire fixation becoming less popular than it used to be?

Answer 16

Due to it being awkward to use and because nails and screws can offer easier options

Question 17

What is a cerclage wire?

Answer 17

A wire that crosses or encircles a fracture fragment

Question 18

In which bones are pins commonly used in fracture fixation?

Answer 18

Small bones and upper limb bones in small children

Question 19

Modern nailing is a technique whereby the nail is inserted into the bone from one end whilst not disturbing the fracture site at all - what is this called?

Answer 19

Antegrade technique

Question 20

What are the 3 most important factors that determine the effectiveness of a nail?

Answer 20

1. Material of which it is made
2. How much of the nail is in contact with the bone for any particular fracture
3. The dimensions and shape of the nail, and its wall thickness if it is hollow

Question 21

Name 5 uses of intramedullary nails?

Answer 21

1. Transverse and short oblique fractures of the trial and femoral shafts
2. Comminuted fractures of tibia and femur, provided cross looking capabilities are available
3. Pathological shaft fractures, especially in osteoporotic bone
4. Delayed or non-union fractures of the shafts of the femur or tibia
5. Selected open fractures

Question 22

What are the main functions of cross screws?

Answer 22

1. Hold apart bone fragments

2. Provide rotatory control

Question 23

Name 5 uses of external fixation in orthopaedics?

Answer 23

1. Limb lengthening
2. Limb shortening
3. Joint fusion (arthrodesis)
4. Correction of angulatory or rotatory deformity
5. Bone segment transportation

Question 24

Name 2 uses of external fixation post-trama?

Answer 24

1. Temporary

2. Definitive

Question 25

What is dynamisation of an external fixator?

Answer 25

Release of a fixator to allow axial (proximal-distal) movements

Question 26

What are the 2 principles for external fixator configuration?

Answer 26

1. The bone/frame construct should be stable (i.e. not rigid)
2. Pin placement must not tether soft tissue or restrict access to wounds

Question 27

When is dynamisation usually used?

Answer 27

1. The soft tissues are well on the way to healing

2. The simple unilateral frame is to be used for definitive fracture control

Question 28

What are the advantages of using external fixators?

Answer 28

1. Can be assembled and fitted quickly which is of value in emergencies
2. They can be adjusted at a later time
3. Can remove beam of the fixator to take clear x-rays
4. Fixators are versatile enough to use in many sites
5. Excellent access to soft tissues

Question 29

What are the 3 main disadvantages of external fixators?

Answer 29

1. Infection of bone-pin interface
2. Pin loosening if weight bearing is applied
3. Soft tissue tethering by pins between skin and bone

Question 30

Name 3 complications of external fixation?

Answer 30

Pins may loosen
Pin tract infection
Soft tissue tethering