MSK

Question 1

What is stage 1 of fracture repair?

Answer 1

Inflammation:
Begins immediately after fracture.
Hematoma and fibrin clot.
Platelets, PMN’s, neutrophils, monocytes, macrophages.
By products of cell death - lysosomal enzymes.

Question 2

What else happens in stage 1 of fracture repair?

Answer 2

Fibroblasts
Mesenchymal and osteoprogenitor cells.
Angiogenesis - macrophages produce angiogenic factors under hypoxic conditions.

Question 3

How might people affect inflammation?

Answer 3

NSAID’s
Loss haematoma - open fractures, surgery.
Extensive tissue damage - poor blood supply.

Question 4

What are the different growth factors in Platelet concentrates?

Answer 4

"buffy coat" 
Platelet-derived growth factor (PDGF)
Transforming growth factor-beta (TGF-B)
Insulin like growth factor (IGF)
Vascular endothelial groth factor (VEGF)

Question 5

What is stage 2 of fracture repair?

Answer 5

Soft callus 
Begins when pain and swelling subside. 
Lasts until bony fragments are united by cartilage or fibrous tissue. 
Some stability of fracture. 
Angulation can still occur.
Continued increase in vascularity.

Question 6

How can people affect soft callus?

Answer 6

Replace cartilage - DMB (demineralised bone matrix)

Jump straight to bone - bone graft, bone substitutes.

Question 7

What is a autogenous cancellous bone graft?

Answer 7

Gold standard
Osteoconductive
Osteoinductive
Best choice for the majority of bone graft needs.

Question 8

What is stage 3 of fracture repair?

Answer 8

Hard callus
Conversion of cartilage to woven bone.
Typical long bone fracture - Endochondral bone formation.
Increasing rigidity - “secondary bone healing”
Obvious Callus.
Membranous bone formation.

Question 9

What is stage 4 of fracture repair?

Answer 9

Bone remodelling.
conversion of woven bone to lamellar bone.
Medullary canal is reconstituted.
Bone responds to loading characteritics of Wolff’s Law.

Question 10

What is a strain?

Answer 10

Degree of instability is best expressed as magnitude of strain.
If strain is too low mechanical induction of tissue differentiation fails.
Too high and healing process does not progress to bone formation.

Question 11

What can cause Delayed union (failure to heal in expected time)?

Answer 11

High energy injury. 
Distraction. 
Instability
Infection 
Steroids 
Immune suppressants
Smoking 
warfarin 
NSAID
Ciprofloxacin

Question 12

What can cause Non Union?

Answer 12

Failure to heal.
Failure calcification fibrocartilage.
Instability - excessive osteoclasisis. 
Abundant callus formation.
Pain and tenderness. 
Persistant fracture line. 
Sclerosis.

Question 13

What are some of the alternative managements that could be considered?

Answer 13

Different fixation.
Dynamisation.
Bone grafting.