Fracture assessment and classification

Question 1

What are you looking for in thoracic radiographs after a traumatic fracture?

Answer 1

Pulmonary contusions
Pneumothorax
Fractured ribs
Other, e.g. a ruptured diaphragm

Question 2

Orthopaedic signalment of young animals

Answer 2

More prone to physeal fractures than (non-physeal) luxations

Question 3

Orthopaedic signalment of elderly animals that have obtained a fracture after minimal trauma

Answer 3

Pathological fracture

Question 4

Orthopaedic signalment differences between male and female animals

Answer 4

Male animals more prone to traumatic fractures (increased tendency to stray)

Question 5

What fracture type are Springer Spaniels prone to?

Answer 5

Humeral condylar fractures

Question 6

What fracture type are bull terriers and greyhounds prone to?

Answer 6

Avulsions of the tibial tuberosity

Question 7

Orthopaedic signalment of toy breeds

Answer 7

Prone to distal radial and ulnar fractures after minimal trauma

Question 8

Orthopaedic signalment of athletic animals e.g. greyhounds and lurchers

Answer 8

Commonly sustain fractures of accessory carpal, radial carpal, and central tarsal

Rarely seen in other dogs

Question 9

Direct fractures

Answer 9

Occur after direct trauma. Often high energy fractures with associated extensive soft tissue.

Question 10

Indirect fractures

Answer 10

Fracture occurs some distance from the point of application of force and they tend to occur at weak points in the bone.

Fractures can be sustained after minimal trauma for example fractures of the distal radius and ulna are seen in toy breeds after a fall.

Fractures of the humeral condyle also occur in skeletally immature (3-5mth) toy breed puppies after jumping off chairs or out of owners’ arms.

Question 11

Fatigue or stress fractures

Answer 11

Occur because of accumulated microdamage to bone & may lead to eventual complete fracture.

Question 12

Pathological fractures

Answer 12

Fractures can occur after minimal trauma through abnormal bone such as neoplasms (osteosarcoma) or osteoporotic bone (nutritional secondary hyperparathyroidism).

Question 13

Muscular action fractures

Answer 13

Fractures can occur secondary to a forceful muscular contraction when the joint or limb is in a fixed position for example avulsion fractures.

Question 14

What is important to check for in a fractured limb, especially prior to any surgical intervention?

Answer 14

Deep pain sensation

Question 15

Fracture classification points (10)

Answer 15

1. Cause of fracture
2. Communication with external environment
3. Extent of bony damage
4. Number and position of fragments
5. Direction of fracture lines
6. Location
7. Forces acting on the fracture/displacement
8. Stability
9. Degree of complexity and involvement of other tissues
10. Age

Question 16

How can the cause of a fracture be defined?

Answer 16

Extrinsic
- direct
- indirect

Intrinsic
- muscular
- pathological
- stress

Question 17

How can the communication with the external environment of a fracture be defined?

Answer 17

Closed
Open

Question 18

Golden period of treating an open fracture

Answer 18

4-6 hours after injury - can effectively be considered a closed fracture

If open more than 6hrs must be considered infected and treated accordingly.

Question 19

Typres of incomplete fractures

Answer 19

Greenstick

Fissure

Depressed

Question 20

Greenstick fractures

Answer 20

occurs in young animals with a fractured cortex on one side together with plastic deformation of the transcortex

may be stable and should heal providing disruptive forces are neutralised.

Question 21

Fissure fractures

Answer 21

often associated with comminuted fractures

can open if inappropriate fixation methods are used potentially making a fracture more complicated.

Question 22

Depression fractures

Answer 22

Usually occur in the skull and are the result of multiple fissures with anatomical displacement of a section of flat bone in the direction of the force.

Further displacement into the cavity must be resisted but anatomical reconstruction is not always necessary unless the displacement is resulting in a problem due to pressure on the underlying structures.

Question 23

Simple fracture

Answer 23

two pieces

Question 24

Comminuted fracture

Answer 24

fractures with more than two pieces and unstable.

All the fracture lines are communicating

Risk of complications is higher with this type of fracture, because of lack of vascularity at the fracture site and associated soft tissue injury.

Question 25

Segmental fractures

Answer 25

fractures with three or more fragments with fracture lines that do not meet at a common point Will need surgical anatomical reconstruction. Blood supply to the fragments may be suboptimal and sequestration may occur.

Question 26

Transverse fracture

Answer 26

fracture line is perpendicular to the long axis of the bone may be able to be manipulated into position and retain axial alignment (resisting compression). Need to be fixed with compression though as otherwise there will be too much movement.

Question 27

Oblique fracture

Answer 27

fracture line is diagonal to the long axis of the bone have little axial stability when reduced and have to be held in position artificially.

Question 28

Spiral fracture

Answer 28

the fracture curves around the bone have little axial stability when reduced and have to be held in position artificially.

Question 29

Locations of fractures

Answer 29

Diaphyseal a. Proximal b. Midshaft c. Distal Metaphyseal Epiphyseal (Salter Harris classification) Condylar Articular

Question 30

Which location of fractures heal quickest?

Answer 30

metaphyseal and epiphyseal

Question 31

Avulsion fractures

Answer 31

fractures affect a fragment of bone at the site of insertion of a muscle tendon or ligament. fixation must counteract the strong muscular pull (eg by using pins and figure of eight tension band wire).

Question 32

Impaction fractures

Answer 32

occurs when a bony fragment (generally cortical) is forced or impacted into cancellous bone – typically occurs at the end of long bones relatively uncommon in small animals and are often stable as a result of the interaction of the two fracture ends. If realignment is necessary the fragments have to be disengaged and held apart by fixation to prevent shortening

Question 33

Compression fractures

Answer 33

occurs when cancellous bone collapses and compresses upon itself – usually vertebral body. rarely subject to surgical reduction unless adjacent elements are compromised – generally heal very quickly.

Question 34

Overriding fracture

Answer 34

describe direction the most distal fragment has displaced in relation to the proximal fragment e.g. displaced proximal, cranial and medial most fractures show overriding and one can anticipate problems at reduction if significant overriding has occurred especially in well-muscled animals and in proximal long bones.

Question 35

Stable fracture

Answer 35

those in which the fragments interlock, providing resistance to collapse

Question 36

Unstable fractures

Answer 36

fracture fragments do not interlock – type of fracture more common.

Question 37

What are the degrees of complexity and involvement of other tissues in a fracture?

Answer 37

Severe muscle damage Nerve damage Vessel damage

Question 38

Recent fracture

Answer 38

sharp fracture edges

Question 39

Older fractures

Answer 39

resorption of sharp edges, possibly some callus formation Old fractures may be more difficult to reduce than fresh fractures. Old fractures include non or delayed union fractures which need special consideration.

Question 40

What are the most urgent fractures

Answer 40

Open fractures and fractures of the skull or spine - most urgent Articular fractures and dislocations should be dealt with within 24 to 48 hours Long bone fractures should be treated within 5-7 days

Question 41

When should intramedullary pins be used for?

Answer 41

the humerus, femur, tibia, proximal ulna, metacarpal, metatarsal and os calcaneus bones NOT radial or mandibular fractures

Question 42

What is external skeletal fixation best used for

Answer 42

Lower limb bones Avoid where there are large muscle masses surrounding bones

Question 43

Fixation of bones in young animals

Answer 43

Young animals (less than 6 months of age) heal rapidly so smaller and weaker implants can be used as stability does not need to be maintained for such a long period (adaptation osteosynthesis). If physes are still open then an implant should be selected that will minimally damage these and allow continued growth. In young animals the bone is relatively soft and screws will easily strip their thread.

Question 44

Bone quality and fracture repair

Answer 44

In osteopenic bone screw holding is poor. If there is underlying bone disease such as nutritional secondary hyperparathyroidism then fractures may be best treated conservatively.

Question 45

Treatment of fractures involving the joint surfaces

Answer 45

Perfect reduction of the articular surface Using rigid internal fixation interfragmentary compression of the fracture gap - using lag screws (+/- plates) Early mobilisation and use of the joint is important to minimise stiffness.

Question 46

What to do if multiple limb involvement in a fracture repair

Answer 46

the optimal or most rigid fixation method should always be chosen as the repaired fractures will be loaded to a far greater degree than in solitary injuries.

Question 47

What forces does a transverse fracture have innate resistance to?

Answer 47

Shear Very good against axial compression

Question 48

What forces does an oblique/spiral fracture have innate resistance to?

Answer 48

Bending Torsion

Question 49

What forces does a comminuted fracture have innate resistance to?

Answer 49

None

Question 50

What forces does an intramedullary pin have innate resistance to?

Answer 50

Bending

Question 51

What forces does a interlocking nail have innate resistance to?

Answer 51

Bending Shear Axial compression (++) Torsion

Question 52

What forces does an ESF have innate resistance to?

Answer 52

Bending (++) Shear Axial compression Torsion

Question 53

What forces do plates and screws have innate resistance to?

Answer 53

Bending Shear (++) Axial compression (+++) Torsion (++)