Fracture class and assessment (Lewis) Flashcards
(37 cards)
1
Q
Strength of bone dependent on
A
- material properties
- structural properties
- rate of load applied
- viscoelastic
- Orientation of applied load
- anisotropic
2
Q
Wolf’s law
A
Bone will form in response to forces it’s subject to
3
Q
Fracture mechanics
Types of stress
A
- Tension
- attachments of ligments or tendons
- Compression
- aka: axial loading
- Shear
- think of it as eccentric loading (making a parallelogram out of a box)
- Bending
- Torsion
4
Q
Tension
A
- Produces elongation
- Creates avulsion fractures
- Occurs at apophyses - traction physes (immature dogs)
- olecranon
- Calcaneus
- tibial tuberosity
5
Q
Compression
A
- Opposite force of tension
- Not a common type of fracture
- can happen in vertebral bodies (cancellous bone)
- Tends to create short oblique fractures
- Bone is strongest in this mode of loading
6
Q
Shear
A
- Eccentric loading of a bone’s surface
- Bone is weakest in this mode of loading
- lateral condylar fracture (when small dog jumps out of arms)
7
Q
Bending
A
- Results in compressive and tensile forces
- Causes short transverse or short oblique fractures
- often with butterfly thingy
- Fracture initiates on tension surface
8
Q
Torsion
A
- Rotational forces applied along long axis of the bone
- Results in spiral fractures
9
Q
Descriptive fracture classification
Important because
A
- Good communication
- Complexity
- Equipment
- Prognosis
- Concurrent injuries
- Systemic dz
- Cost
10
Q
Configuration
Incomplete fractures
A
- Greenstick: opposing cortices involved
- young animals
- bending or torsional forces
- can be oblique or spiral fractures
- Fissure: involves only one cortex
11
Q
Configuration
Complete fractures
A
- Continuity of bone is disrupted
- Transverse
- Oblique
- Spiral
- Comminuted
- Segmental
12
Q
Transverse fractures
*what force would bone be stable to if anatomically reduced?
A
- propagates perpendicular to bone’s long axis
- smooth or serrated fracture surfaces
- generally result of bending forces
- Some inherent stability
- Stable to
- shear forces
13
Q
Oblique fracture
A
- Fracture line rund diagonally to bone’s long axis
- opposing fracture surfaces (cortices) are in same plane
- generally result of axial compression and bending nforces
- limited inherent stability: would succumb to all forces if reduced
14
Q
Spiral fracture
A
- Fracture line runs diagonally to bone’s long axis
- Opposing fracture surfaces (cortices) are in different planes
- Generally result of torsional forces
- Inherently stable if reduced
15
Q
Comminuted fractures
A
- At least three fracture segments
- Fracture lines intersect
- High(er) energy trauma
- Multiple forces involved
*think about damage to all the soft tissue when you see this: KE=1/2mv2
16
Q
Segmental fracture
A
- At least three fracture segments
- will have a middle cylinder of bone
-
Fracture lines do not intersect
- very difficult to reduce and stabilize
- Bending and other forces
- May have a large avascular segment
- upsets main vascular medullary supply
*Not seen as frequently as people
17
Q
Open Fracture Classification
A
- Type 1
- Type 2
- Type 3a
- Type 3b
- Type 3c
*used to be called compound fracture
18
Q
Type I open fracture
A
- clean soft tissue laceration < 1cm
19
Q
Type II open fracture
A
- Soft tissue laceration > 1 cm
- mild trauma, no flaps or avulsion
*Needs more aggressive treatment
20
Q
Type IIIa open fracture
A
- Soft tissue available for wound coverage despite large laceration
- flaps or high energy trauma
21
Q
Type III b open fracture
A
- Extensive soft tissue injury, loss
- Periosteum stripped and bone exposed
22
Q
Type III c open fracture
A
- Arterial supply to the distal limb damaged
- Arterial repair indicated
*street pizza, establish prognosis and aggressive tx if trying to treat
23
Q
Fracture classification
Anatomic location
A
- Diaphyseal
- cortical bone; haversion system; dense bone; slow healing; very little soft tissue
- Metaphyseal
- mainly cancellous bone; lots of soft tissue; faster turn over; less mechanical forces
- Physeal (Salter-Harris)
- impacts growth
- Epiphyseal
- usually also articular fractures
- Articular
- goal: anatomic reduction and rigid fixation
24
Q
clnic question:
Articular fracture of the acetabulum, what do we want to do?
A
- Anatomic reduction
- Rigid internal fixation
25
Salter-Harris Classification
* Class I
* separation through the physis (epiphysis comes off)
* Class II
* comes through metaphysis, goes through physis
* Class III
* comes through epiphysis, goes through the physis
* Class IV
* comes through metaphysis, physis and epiphysis
* Class V
* compressive injury
\*higher classification, worse prognostic indication for continued growth from growth plate (in humans), in vet med, most fractures cause growth plate to close
26
Growth from growth plate
* Starts at reserve zone at epiphysis
* cells mature and migrate to metaphysis
27
**Boards question:**
Through what layer of the growth plate to Salter Harris fractures occur
Zona hypertrophy
## Footnote
\*growing cells bigger, mostly water, not strong
\*dogs cats have complex physes, humans tend to have straight physes so maybe this is a trick question...
28
Articular Fracture
* Can be complete or incomplete
* Involves articular cartilage and subchondral bone
* **very important to recognize**
* **demand anatomic reduction and rigid internal stabilization**
29
Fracture description
INCLUDE:
1. Open/closed
2. Configuration
3. Location
4. Right/Left
5. Bone
6. Displacement: distal segment relative to proximal segment
30
Describe this fracture:
* Closed
* Spiral
* Distal (dia-) metaphyseal
* fracture of left humerus
* with caudal & lateral displacement
31
Fracture diagnosis
1. History
2. Dysfunction
3. Pain
4. Local trauma
5. Abnormal conformation
6. crepitus
7. radiographs
32
Fracture diagnosis
Radiographic signs
* A disturbance or break in continuity
* Radiolucent line
* Summation
* or lack
* **Always include the joint proximal and distal to the fracture**
* **Always obtain two orthogonal views of the bone**
* **elbow**
* **sedate if necessary**
33
Fracture assessment score
* Developed to assist surgeons in decision making
* Consider risk factors
* Assess a score based on risk
34
Clinical fracture assessment
* 1 end (caution)
* Poor client compliance
* Poor patient compliance
* Wimp
* High comfort level required
* 10 end (little risk)
* Good client compliance
* Good patient compliance
* Stoic
* Comfort level not a consideration
35
Mechanical Fracture Assessment
* 1 (caution)
* non-reducible fragments
* multiple limb injury
* Giant breed
* 5
* Reducible fragments
* Preexisting Clinical Disease
* Large Dog
* 10 (caution)
* Compression
* Single Limb
* Toy Breed
36
Biologic Fracture Assessment
* 1 (caution)
* old patient
* poor health
* poor soft tissue envelope
* Cortical bone
* High velocity injury
* Extensive approach
* 10 (minimal risk)
* juvenile
* excellent health
* good soft tissue envelope
* Cancellous bone
* low velocity injury
* closed
* reduction
37
Interpretation of fracture assessment
* Average all scores
* High scores better
* Low scores
* slow or complicated healing
* greater reliance on implants for longer periods of time
