fractures biomechiics and classification Flashcards
forces that can cause and act on a fracture
- Compression
- Tension
- Bending
- Torsion
-forces will affect how a fracture forms and heals
-Most (but not all) fractures are acted upon by
a combination of forces.
-The forces that will act upon a fracture once the pieces are realigned are the forces that will need to be neutralized in order for the fracture to heal.
tension on bone
- Results in distraction
- Most common at apophyses,
where large muscle masses pull
on the bone when the limb is
bearing weight
-A fracture caused by a tensile force is
called an avulsion.
- Examples: triceps/olecranon,
quadriceps/tibial tuberosity
bending force on bone
-Happens when a force is
applied perpendicular to
the long axis of a bone
- Can also result from
compression when the
proximal and distal ends
of the bone are offset - Results in angulation
Compression and
tension sides of a bone
torsion
casts and splints
Casts/Splints:
* Good against bending
* Fair against torsion
* Do virtually nothing for compression or tension
Intramedullary Pins
Good against bending…and that’s IT.
wires
- Wires: Help to control tension and produce
compression; ineffective against other forces
interlocking nails
-good agaisnt all forces
external skeletal fixators
good against all forces…as long
as an appropriately strong configuration is chosen
bone plates
-good against all forces
fracture classification 1 is it open or closed
Closed: no wound connects the bone with the outside world
Open (used to be called “compound”): there is, or has been, a
connection between bone and the outside world
fracture classification 2 What is the fracture configuration and
degree of comminution?
-greenstick
-fissure
-saucer
-complete
-transverse
-oblique: A long oblique fracture is at least
twice the diameter of the bone
at that point
-spiral
-Comminuted Fractures =More than two fragments
Factors influencing fracture configuration
Energy applied
Type and direction of force applied
Which bone is injured
Age of animal
fracture classification 3 what part of the bone is fractured?
What part of the bone is fractured?
* Proximal, distal, or middle
third of the bone
* Fractures in the middle of
the bone are called
“midshaft.”
- Articular
- Physeal
- Metaphyseal
- Diaphyseal
- Condylar/Supracondylar
- Trochanteric
How is the fracture displaced?
-Describe the location of the most distal
fragment relative to the position of the most
proximal fragment.
-* If fragments are angled relative to each other, describe where the apex
of the angle points in that
plane
Bonus Classifications! Fracture classification due to
cause
- traumatic
- pathologic
- fatigue
- iatrogenic
external coaputation
limb splinting
* Casts
* Splints
* Bandages
* Slings
* Braces
external skeletal fixation
bone splinting
Forces neutralized by external coaptation
- Bending
- Torsion (depends on fit of coaptation
device)
Casts: Appropriate Uses
- Definitive stabilization of some fractures
- Joint immobilization
- Support after arthrodesis
- Protection of repair for recovery (large
animals
splints uses
- Definitive repair of relatively stable fractures (eg. adjacent bone intact, well-reduced transverse fracture)
- Repair of fractures in young animals
- Support of operative repairs/ reduced luxations
- Temporary stabilization
Braces (orthotics or orthoses)
Like splints but with minimal padding
* Designed to be worn part time
* May allow motion in one plane but
not another
orthotics
- Designed to be worn only part of the day
- Can be custom-made or off the shelf
- Currently minimal evidence as to efficacy
-need to be custom made or well fitted to work
