SA Ortho - Bone Healing Stable/unstable

Question 1

fracture injuries

Answer 1

Soft tissue damage
Instability of bone
Loss of function

Question 2

Fracture fixation purpose

Answer 2

Reestablish mechanic support

Question 3

What does bone depend on to heal

Answer 3

Age, location, presence of necrotic debris, vascularity availability, stability, distance between fragments

Question 4

Stable conditions for bone healing

Answer 4

Direct apposition of bone
Direct or primary bone healing

Question 5

Unstable bone healing conditions

Answer 5

Connective tissue, fibrocartilage then bone
Indirect or secondary bone healing

Question 6

Most important factor in bone healing

Answer 6

Vascular

Question 7

Why is stability key in healing?

Answer 7

Allows vessels and cells to cross fracture line effectively
Interruptions in this connection from instability regresses progress

Question 8

Distance can cause what in healing

Answer 8

If distance is too great the fracture will experience motion and callus will be large as a result

Question 9

Stages of bone healing

Answer 9

Coagulation - fracture hematoma
Inflammation - clean up
Granulation - repair
Maturation - remodeling

Question 10

Inflammation

Answer 10

Neutrophils
Macrophages
Osteoclasts
Help clean up the area, remove any bacteria present

Question 11

Granulation

Answer 11

More stability = more cartilage
Fibroblasts produce fibrous tissue
Chondrocytes produce fibrocartilage
Osteoblasts produce bone

Question 12

Stable conditions - type of callus

Answer 12

No gap due to good blood supply - direct or primary healing

Question 13

Unstable conditions - callus type

Answer 13

Gap with good blood supply will result in indirect or secondary bone healing

Question 14

Contact areas in primary healing

Answer 14

Contact between fragments - gap should be <1mm
GOOD BLOOD SUPPLY

Question 15

Structures in contact area in primary healing

Answer 15

Osteoclasts create tunnels across fracture line
Vessels follow
Osteoblasts fill in tunnel in concentric ring

Question 16

What location is NOT ideal for a callus ?

Answer 16

Joints ! Not helpful v v bad

Question 17

Gap area <200Um

Answer 17

Hematoma in gap
Bv and mesenchymal cells
Osteoblasts deposit lamellar bone
Ideal gap space

Question 18

Gap >200uM but <1mm

Answer 18

Hematoma in gap
BV and mesenchymal cells
Osteoblasts deposit woven bone haphazard

Question 19

Indirect healing

Answer 19

Good blood supply
Large gaps
Not rigidily stable

Question 20

Tissue replacement in indirect bone healing

Answer 20

Fibrous tissue first
Fibrocartilage
Bone-woven

Question 21

Features of maturation

Answer 21

Remodeling
Modeling
Osteoclasts/blast

Question 22

Direct healing

Answer 22

Minimal callus
Takes longer to achieve full bone strength

Question 23

Indirect healing

Answer 23

More callus
Remodels faster and stronger but callus may impair

Question 24

Which is better healing for articular fractures

Answer 24

Direct - as smooth as possible

Question 25

Factors in describing bone healing

Answer 25

Mechanical Biological Clinical

Question 26

Each factor is scored from 1-10

Answer 26

1=factor does not favor rapid bone healing 10=factor favor bone healing

Question 27

Factors for an assessment scores

Answer 27

Age, health, condition of soft tissue, type of bone (cortical, cancellous) type of injury, open or closed fracture

Question 28

Low scores on fracture assessment

Answer 28

Implants bridge fracture and support all loads Strong durable Plate, external fixator, interlocking nail

Question 29

Mid score fracture assessment

Answer 29

Less implant strength and endurance needed Plates and external fixators, interlocking nail, IM pins and wires

Question 30

High scores on fracture assessment

Answer 30

Bone and implants share load and rapid healing expected External fixator, IM pins and wires, external coaptation

Question 31

Vascularity integrity

Question 32

Fracture location

Answer 32

Metaphyseal heal faster than diaphaseal Distal antebrachium in mini dogs and tibial diaphyseal heal slowwwww

Question 33

Degree of immobilization

Answer 33

More rigid fixation = faster healing

Question 34

Fracture type

Answer 34

More complicated the fracture = slower healing

Question 35

Degree of post-reduction apposition

Answer 35

Better apposition = faster healing

Question 36

Age of animal in healing

Answer 36

Younger = faster

Question 37

Degree of location in healing

Answer 37

Fractures w lots of soft tissue damage - slower healing

Question 38

Degree of bone loss in healing

Question 39

Types of bones involved in healing

Answer 39

Cancellous bone = rapid + rich blood supply Cortical bone = slower (direct healing)

Question 40

Local malignancy in healing

Answer 40

Pathologic fractures can heal just slowly

Question 41

Corticosteroids in healing

Answer 41

Use of corticosteroids will slow healing - inhibit differentiation of osteoblast form mesenchymal cells and decrease rate of synthesis of major components of bone matrix