Fracture assessment and classification Flashcards
What are you looking for in thoracic radiographs after a traumatic fracture?
Pulmonary contusions
Pneumothorax
Fractured ribs
Other, e.g. a ruptured diaphragm
Orthopaedic signalment of young animals
More prone to physeal fractures than (non-physeal) luxations
Orthopaedic signalment of elderly animals that have obtained a fracture after minimal trauma
Pathological fracture
Orthopaedic signalment differences between male and female animals
Male animals more prone to traumatic fractures (increased tendency to stray)
What fracture type are Springer Spaniels prone to?
Humeral condylar fractures
What fracture type are bull terriers and greyhounds prone to?
Avulsions of the tibial tuberosity
Orthopaedic signalment of toy breeds
Prone to distal radial and ulnar fractures after minimal trauma
Orthopaedic signalment of athletic animals e.g. greyhounds and lurchers
Commonly sustain fractures of accessory carpal, radial carpal, and central tarsal
Rarely seen in other dogs
Direct fractures
Occur after direct trauma. Often high energy fractures with associated extensive soft tissue.
Indirect fractures
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.
Fatigue or stress fractures
Occur because of accumulated microdamage to bone & may lead to eventual complete fracture.
Pathological fractures
Fractures can occur after minimal trauma through abnormal bone such as neoplasms (osteosarcoma) or osteoporotic bone (nutritional secondary hyperparathyroidism).
Muscular action fractures
Fractures can occur secondary to a forceful muscular contraction when the joint or limb is in a fixed position for example avulsion fractures.
What is important to check for in a fractured limb, especially prior to any surgical intervention?
Deep pain sensation
Fracture classification points (10)
- Cause of fracture
- Communication with external environment
- Extent of bony damage
- Number and position of fragments
- Direction of fracture lines
- Location
- Forces acting on the fracture/displacement
- Stability
- Degree of complexity and involvement of other tissues
- Age
How can the cause of a fracture be defined?
Extrinsic
- direct
- indirect
Intrinsic
- muscular
- pathological
- stress
How can the communication with the external environment of a fracture be defined?
Closed
Open
Golden period of treating an open fracture
4-6 hours after injury - can effectively be considered a closed fracture
If open more than 6hrs must be considered infected and treated accordingly.
Typres of incomplete fractures
Greenstick
Fissure
Depressed
Greenstick fractures
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.
Fissure fractures
often associated with comminuted fractures
can open if inappropriate fixation methods are used potentially making a fracture more complicated.
Depression fractures
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.
Simple fracture
two pieces
Comminuted fracture
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.
Segmental fractures
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.
Transverse fracture
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.
Oblique fracture
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.
Spiral fracture
the fracture curves around the bone
have little axial stability when reduced and have to be held in position artificially.
Locations of fractures
Diaphyseal
a. Proximal
b. Midshaft
c. Distal
Metaphyseal
Epiphyseal (Salter Harris classification)
Condylar
Articular
Which location of fractures heal quickest?
metaphyseal and epiphyseal
Avulsion fractures
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).
Impaction fractures
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
Compression fractures
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.
Overriding fracture
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.
Stable fracture
those in which the fragments interlock, providing resistance to collapse
Unstable fractures
fracture fragments do not interlock – type of fracture more common.
What are the degrees of complexity and involvement of other tissues in a fracture?
Severe muscle damage
Nerve damage
Vessel damage
Recent fracture
sharp fracture edges
Older fractures
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.
What are the most urgent fractures
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
When should intramedullary pins be used for?
the humerus, femur, tibia, proximal ulna, metacarpal, metatarsal and os calcaneus bones
NOT radial or mandibular fractures
What is external skeletal fixation best used for
Lower limb bones
Avoid where there are large muscle masses surrounding bones
Fixation of bones in young animals
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.
Bone quality and fracture repair
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.
Treatment of fractures involving the joint surfaces
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.
What to do if multiple limb involvement in a fracture repair
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.
What forces does a transverse fracture have innate resistance to?
Shear
Very good against axial compression
What forces does an oblique/spiral fracture have innate resistance to?
Bending
Torsion
What forces does a comminuted fracture have innate resistance to?
None
What forces does an intramedullary pin have innate resistance to?
Bending
What forces does a interlocking nail have innate resistance to?
Bending
Shear
Axial compression (++)
Torsion
What forces does an ESF have innate resistance to?
Bending (++)
Shear
Axial compression
Torsion
What forces do plates and screws have innate resistance to?
Bending
Shear (++)
Axial compression (+++)
Torsion (++)
