Fracture class and assessment (Lewis) Flashcards Preview

Ortho sx > Fracture class and assessment (Lewis) > Flashcards

Flashcards in Fracture class and assessment (Lewis) Deck (37):
1

Strength of bone dependent on

  • material properties
  • structural properties
  • rate of load applied 
    • viscoelastic
  • Orientation of applied load
    • anisotropic

2

Wolf's law

Bone will form in response to forces it's subject to

3

Fracture mechanics

Types of stress

  • 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

Tension

  1. Produces elongation
  2. Creates avulsion fractures
  3. Occurs at apophyses - traction physes (immature dogs)
    • olecranon
    • Calcaneus
    • tibial tuberosity

5

Compression

  1. Opposite force of tension
  2. Not a common type of fracture
    • can happen in vertebral bodies (cancellous bone)
  3. Tends to create short oblique fractures
  4. Bone is strongest in this mode of loading

6

Shear

  1. Eccentric loading of a bone's surface
  2. Bone is weakest in this mode of loading
    • lateral condylar fracture (when small dog jumps out of arms)

7

Bending

  1. Results in compressive and tensile forces
  2. Causes short transverse or short oblique fractures
    • often with butterfly thingy
  3. Fracture initiates on tension surface

8

Torsion

  1. Rotational forces applied along long axis of the bone
  2. Results in spiral fractures

9

Descriptive fracture classification

Important because

  • Good communication
    • Complexity
    • Equipment
    • Prognosis
    • Concurrent injuries
    • Systemic dz
    • Cost

10

Configuration

Incomplete fractures

  1. Greenstick: opposing cortices involved
    • young animals
    • bending or torsional forces
      • can be oblique or spiral fractures
  2. Fissure: involves only one cortex

11

Configuration

Complete fractures

  • Continuity of bone is disrupted
    1. Transverse
    2. Oblique
    3. Spiral
    4. Comminuted
    5. Segmental

12

Transverse fractures

*what force would bone be stable to if anatomically reduced?

  • 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

Oblique fracture

  • 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

Spiral fracture

  • 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

Comminuted fractures

  • 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

Segmental fracture

  • 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

Open Fracture Classification

  • Type 1
  • Type 2
  • Type 3a
  • Type 3b
  • Type 3c

*used to be called compound fracture

18

Type I open fracture

  • clean soft tissue laceration < 1cm

19

Type II open fracture

  • Soft tissue laceration > 1 cm
  • mild trauma, no flaps or avulsion

*Needs more aggressive treatment

20

Type IIIa open fracture

  • Soft tissue available for wound coverage despite large laceration
  • flaps or high energy trauma

21

Type III b open fracture

  • Extensive soft tissue injury, loss
  • Periosteum stripped and bone exposed

22

Type III c open fracture

  • Arterial supply to the distal limb damaged
  • Arterial repair indicated

*street pizza, establish prognosis and aggressive tx if trying to treat

23

Fracture classification

Anatomic location

  • 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

clnic question:

Articular fracture of the acetabulum, what do we want to do?

  • 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

*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:

Q image thumb

  • 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