10. Healing of fractures

Question 1

What are the three stages of healing?

Answer 1

1. Inflammatory
2. Reparative
3. Remodelling

Question 2

Describe the inflammatory stage of healing:

Answer 2

Haematoma forms at injury site. Macrophages and inflammatory leukocytes move into damaged area to scavenge debris. Begin producing pro-inflammatory agents that initiate healing. Thick mass of callus forms from haematoma.
Time frame: Hours to days

Question 3

Describe the reparative stage of healing:

Answer 3

Osteoblasts are recruited.
Soft callus: Inflammation triggers cell division and the growth of new blood vessels. Chondrocytes secrete collagen and proteoglycans, creating fibrocartilage that forms the soft callus. Is organised and reorganised into hard callus.
Hard callus: Through endochondrial ossification and direct bone formation, woven bone replaces soft callus to create a hard callus around the broken fragments of bone. Weaker than normal bone, not able to palpitate or move.

Question 4

Describe the remodelling stage of healing:

Answer 4

Over time, mechanically strong and highly organised cortical bone replaces weaker, disorganised bone. Epiphyseal realign. External callus is organically removed by osteoclasts.

Question 5

Bone growth and remodelling:

Answer 5

35 years old, very little changes. Requires continuous osteoblasts, osteoclasts, osteocytes and stem cells.

Question 6

Outcomes of complications to healing times:

Answer 6

Delayed union: Takes twice as long
Non-union: Aka pseudoarthrosis.
Malunion: Bone heals in wrong position and has to be refracted and set again.
Refracturing: If internal fixations in place for too long.

Question 7

Time frame of stages:

Answer 7

7-14 days: Granulation tissue forming between fragments. Leads to vascularisation, small broken pieces get reabsorbed (phagocytosis)
4-16 weeks: In reparative phase. Osteoblasts lay down woven matrix. Soft newly formed callus.
16 weeks to several years: Remodelling (is faster in children)

Question 8

Healing times:

Answer 8

Phalanges: 3 weeks
Metacarpals and metatarsals: 4-6 weeks
Distal radius: 4-6 weeks
Radius and ulna: 8-10 weekss
Humerus: 6-8 weeks
Femoral neck: 12 weeks
Femoral shaft: 12 weeks
Tibia: 12 weeks.

Question 9

Treatment

Answer 9

Once in position, bone is immobilised for union.

Operative or non-operative: External fixation (traction) internal fixations, sometimes a splint first. Casting.

Question 10

Aim and function of casting:

Answer 10

Aim: To immobilise, prevent displacement, reduce pain, allow healing to occur
Function: Immobilise joint above and below.
OT: Trying to minimise amount of cast whilst maximising function

Question 11

Name the 7 types of casts

Answer 11

Short arm cast
Long arm cast
Arm cylinder cast
Unilateral hip spica cast
One and one half hip spica cast
Bilateral long leg hip spica cast
For babies: Abduction boot cast, short leg hip spica cast

Question 12

What does FWP and PWB mean:

Answer 12

Full weight bearing
Partial weight bearing: 50% or less, not full weight. Not just toe, put part of foot pressure. Rest of weight onto crutches.

Question 13

What does NWB and WBAT mean?

Answer 13

NWB: None weight bearing: Have to completely lift leg up, no contact with ground.
WBAT: Depends on pain, pain is what limits you.

Question 14

What does ORIF stand for?

Answer 14

Open reduction and internal fixation

Question 15

Explain the use of K wires

Answer 15

Temporary and definitive treatment of fractures.
When sole form of fixation: Also use casting or splinting.
Often used with: Patella, proximal humour fracture, hand surgery.