Bone healing

Question 1

Why do we do anatomical reduction for Intraarticular fractures?

Answer 1

To reduce the risk of secondary osteoarthritis

Question 2

Anatomical reduction is done for which type of fractures?

Answer 2

Intra-articular

Question 3

Functional reduction is done for which type of fractures?

Answer 3

Shaft fractures

Question 4

What is absolute stability?

Answer 4

No movement at the fracture site

Question 5

What is relative stability?

Answer 5

Minimal movement at the fracture site

Question 6

Which fractures require absolute stability?

Answer 6

Intra-articular

Question 7

Which fractures require relative stability?

Answer 7

Epiphyseal or metaphyseal

Question 8

The timing to start mobilization depends on:

Answer 8

The stability of the fixation

Question 9

What is the aim of mobilization?

Answer 9

To start as early as possible in order to avoid complications like joint stiffness

Question 10

For a fracture to properly heal, it needs:

Answer 10

1) Good blood supply
2) Stability
3) Good bony opposition (bone on bone contact)

Question 11

What are the types of fracture healing?

Answer 11

1) Primary (Direct)
2) Secondary (Indirect)

Question 12

Secondary bone healing occurs in which type of stability?

Answer 12

Relative stability

Question 13

Primary bone healing occurs in which type of stability?

Answer 13

Absolute stability

Question 14

If someone has a cast, what type of stability is this?

Answer 14

Relative

Question 15

Someone wearing a sling would go through which type of bone healing?

Answer 15

Secondary

Question 16

Which methods provide relative stability?

Answer 16

1) Cast
2) Sling
3) Intramedullary nails
4) K-wires

Question 17

Primary bone healing is only possible with:

Answer 17

1) Fracture gap <2mm
3) Motion at the fracture site <1mm

Question 18

What is consolidation?

Answer 18

Restoring pre-fracture strength

Question 19

What are the 4 stages of bone healing?

Answer 19

1) Hematoma formation & Inflammation
2) Soft callous
3) Hard callous
4) Remodeling

Question 20

How is granulation tissue produced in bone healing?

Answer 20

Hematoma + necrosis release cytokines that:
1) Attract macrophages
2) Promotes neovascularization

= Granulation tissue produced

Question 21

What invades the granulation tissue when forming the soft callous?

Answer 21

1) Fibroblasts
2) Chondroblasts
3) Osteoblasts

Question 22

When does the fracture become sticky (soft callous)?

Answer 22

When the fibrous tissue is replaced by cartilage

Question 23

How does the soft callous becomes a hard callous?

Answer 23

When the cartilage is replaced by woven bone

Question 24

Bone healing between fracture ends resembles:

Answer 24

Endochondral ossification

Question 25

Remodeling is best in: (!!!)

Answer 25

1) Younger children 2) Fractures close to the growth plate

Question 26

What remodeling characteristics of bone facilitates early load and weight bearing?

Answer 26

1) Progressive mineralization of the woven callous 2) Its protuberant shape

Question 27

What characteristics of remodeled bone are suboptimal?

Answer 27

1) High cellularity and water content 2) Amorphous arrangement of collagen fibers 3) Patchy pattern of matrix mineralization

Question 28

The hard callous is replaced gradually with ___ according to:

Answer 28

Lamellar bone; Stresses applied upon it.

Question 29

What does osteoclastic resorption do?

Answer 29

Removes extraneous peripheral bone that isn’t necessary for optimal mechanical function

Question 30

What is absent in primary bone healing?

Answer 30

Massive callous formation

Question 31

What gradually disappears in primary bone healing?

Answer 31

Small fracture lines

Question 32

What is the Haversian remodeling?

Answer 32

The coordinated activity of osteoblasts and osteoclasts to resorb and replace existing cortical bone.

Question 33

What is primary bone healing responsible for?

Answer 33

The perpetual turnover of the skeleton

Question 34

Primary bone healing is a temporary acceleration of:

Answer 34

Haversian remodeling

Question 35

Primary bone healing is carried out by:

Answer 35

Bone metabolizing units

Question 36

Bone metabolizing units contain what at the front end?

Answer 36

Cutting cones

Question 37

Bone metabolizing units are lined by:

Answer 37

Multicellular osteoclasts

Question 38

What is the linear rate of bone resorption?

Answer 38

50µm/day

Question 39

Behind the bone metabolizing units, walls of osteons are lined by:

Answer 39

Osteoblasts

Question 40

Osteoblasts produce osteoid at a rate of:

Answer 40

1µm/day

Question 41

Which 3 tools are used for absolutely stable fractures?

Answer 41

1) Lag screws 2) Compression plates 3) Tension band wiring

Question 42

What are the complications of fracture healing?

Answer 42

1) Malunion 2) Nonunion

Question 43

What is malunion?

Answer 43

Good healing but in an inappropriate position = Compromises the function

Question 44

What is the treatment for malunion?

Answer 44

Osteotomy (break the bone) and fixation in the right position

Question 45

What are the types of nonunion?

Answer 45

1) Hypertrophic 2) Atrophic

Question 46

Where does the problem lie in hypertrophic nonunion?

Answer 46

Inadequate stability of the fracture site (Callous is formed but can’t hold the ends together)

Question 47

Where does the problem lie in atrophic nonunion?

Answer 47

Inadequate vascularity at the fracture site = necrosis at fracture ends

Question 48

What sign is seen on the x-ray in hypertrophic nonunion?

Answer 48

Elephant foot or horse hoof appearance

Question 49

Treatment of hypertrophic nonunion?

Answer 49

Surgical stabilization of the fracture

Question 50

What sign is seen on the x-ray in atrophic nonunion?

Answer 50

Pencil like appearance of fracture ends

Question 51

Treatment of atrophic nonunion?

Answer 51

1) Debridement of the necrotic bone ends 2) Bone grafting 3) Fixation