principles of fracture management

Question 1

what are orthoganal radiographs

Answer 1

two images taken at right angles to each other

Question 2

how do you assess a fracture?

Answer 2

assign a fracture score and assess the forces that will be applied to the fracture, thining about how these can be managed

Question 3

what does fracture score indicate?

Answer 3

gives an indication of the severity and biological nature of the fracture as well as non
biological factors such as owner finances and surgeon’s abilities

In most systems the higher the score the more demanding the fracture will
be to repair, the more robust that repair needs to be and the greater the chance
of complications

Question 4

what patient factors need to be considered with fracture score?

Answer 4

Weight of animal:- heavier have a higher score
Age:- younger animals lower score
Boisterousness and ability to manage cage rest
Concurrent illnesses

Question 5

what fracture factors need to be considered with fracture score?

Answer 5

Type of fracture:- does it allow compression plating or require external fixator, etc.
Open or closed?
Associated soft tissue injuries
Single or one of several fractures

Question 6

what owner factors need to be considered with fracture score?

Answer 6

Will they comply with post-op instructions?
Finances

Question 7

what surgeon factors need to be considered with fracture score?

Answer 7

Are they able to manage this fracture?
Is the correct equipment available?

Question 8

what mechanical factors do you need to thing about when fracture scoring?

Answer 8

is there displacement/ comminution of the fracture

Question 9

what biological factors do you need to thing about when fracture scoring?

Answer 9

young puppy should hear quickly but pathological farcture (Osteosarcomas) wont heal

Question 10

what forces are applied to bones?

Answer 10

• Bending
• Torsion
• Tension
• Axial compression (when this force is applied on oblique fracture surfaces a shear force will be generated)

Question 11

when thinking about plating a bone what do you need to think about regarding forces?

Answer 11

tension and compression
aspects of the long bone - plate needs to be placed on the tension side as will not fail due to tension

All diaphyseal bones are asymmetrically loaded when weight bearing

The mandible is also asymmetrically loaded during mastication

(By some fluke of nature the tension sides of the diaphyseal bones upon which
any plate will be placed are those with the easiest approaches )

Question 12

where is the tension aspect of the femur?

Answer 12

lateral aspect

Question 13

where is the tension aspect of the tibia?

Answer 13

medial aspect

Question 14

where is the tension aspect of the radius?

Answer 14

craniomedial aspect

Question 15

where is the tension aspect of the humerus?

Answer 15

latero-cranio aspect

Question 16

where is the tension aspect of the mandible?

Answer 16

dorsal aspect

Question 17

what is the impact of axial compression on a fracture?

Answer 17

Axial compression this is good if the fracture is transverse (i.e. at right angles to the long bone) or if the fracture interdigitates.

If not then compression of a comminuted (i.e. multiple fragments) or an oblique fracture causes the fracture to collapse or shear

Question 18

what is the impact of tension on a fracture?

Answer 18

Tension produced by ligaments or tendons pulling on one of the bone fragments causes the fracture to be distracted and needs to be overcome with lag screwing or tension bands

Question 19

what is the impact of torsion on a fracture?

Answer 19

Torsion resulting in rotation of the fracture site requires management with plates, external fixator or an interlocking nail

Question 20

what is the impact of bending on a fracture?

Answer 20

Bending occurs due to the asymmetrical nature of the bone loading. A pin in the centre of the medullary cavity is best suited at counteracting this force

Question 21

when does first intension (primary) bone healing occur?

Answer 21

Primary bone healing requires intimate contact of the bone ends preferably under compression.
This requires application of a bone plate and extensive dissection and manipulation of soft tissues

Question 22

when does senond intension (secondary) bone healing occur?

Answer 22

Secondary bone healing does not require accurate reduction of the fracture
e.g. the application of an external fixator without manipulation of the fracture itself or adopting a look but do not touch approach (LBDT) or minimally invasive plate osteosynthesis (MIPO) when a plate is placed through subcutaneous tunnels

Question 23

what is the purpose of fracture repair?

Answer 23

reduce movement and allow the formation of granulation tissue, callus and finally a bone

Question 24

what is strain relating to a fracture

Answer 24

strain - the movement that occurs at the fracture site in realtion to the fracture gap
asmall gapwith large movement - greater strain
tissues will only tolerate a certain level of strain

Question 25

what is the strain theory?

Answer 25

Strain is the change in length over the original length of the fracture. If there is a small gap and much movement then strain is high and the fracture fails to heal as the tissues rupture

The strain that tissues will tolerate reduces as the fracture heals

Question 26

how does a fracture deal with strain that is too high?

Answer 26

To reduce the strain the gap can be widened i.e.

• Resorption of fragment ends increases the fracture gap and hence decreased the strain
• Formation of callus creates greater stability and reduced movement at the fracture site and the strain decreases

Question 27

why is it essential to take post-oerative radiographs for frature repair?

Answer 27

used to assess:
* Alignment of the fracture
* The positioning of implants
* The encroachment of implants into joints or soft tissues or the bridging of growth plates in young animals

Question 28

when do frature repair cases need to be re-examined?

Answer 28

depends on the animals recovery and the type of intervention applied

(eg. an external fixator may require a weekly examination as the complication rate is higher whereas a plate repair may only require an examination at monthly intervals if it is progressing well)

Question 29

when should radiographic reassesment of a fracture repair occur?

Answer 29

• Prior to the removal of implants
• If progression is not as anticipated
• There is evidence of sepsis