Bone Healing

Question 1

Inflammation phase

Answer 1

Bleeding, hematoma formation
Source of progenitor cells
Granulation tissue forms
Osteoblasts, fibroblasts proliferate
Some initial stability from tissue turgidity
Necrotic tissue, bone ends resorbed

Question 2

Repair phase

Answer 2

Soft callus: non ossified fibrous and cartilaginous tissue

Replaced via process of endochondral ossification into woven bone and becomes hard callus

Question 3

Remodelling phase

Answer 3

Begins during repair phase
Continues long after the fracture has healed clinically
Woven bone replaced by laminar, cortical bone
Allows bone to assume more normal shape
Based on stresses experienced by the bone

Question 4

Metaphyseal fracture healing

Answer 4

Forms an internal callus because trabecular/spongy bone is porous
But can be external depending on location

Question 5

Fracture fixation with callus

Answer 5

Intramedullar nail fixation
Fracture healing goes through normal process
Nailing doesnt impart complete stability so you get the callus

Question 6

Primary bone healing

Answer 6

For the fractures that will functionally not do well if allowed to heal with some deformity/abundant callus
Forearm and joints
Rigidly fixed fractures
Direct osteonal healing
A lot of direct contact, the rest fills in with woven bone and remodels from there

Question 7

How long does a fracture in a metaphyseal bone in an adult take to heal?

Answer 7

6-8 weeks

Question 8

Factors that double the time it takes for bone to heal

Answer 8

Elderly
Cortical bone
Open fracture
Smoker
Non compliant patient

Question 9

Causes of nonunion

Answer 9

Instability
Too much stability with gap
Inadequate vascularity
Infection
Nicotine (vasoconstriction)
Medications

Question 10

Malunion

Answer 10

If a bone heals with a deformity

Related to function, not healing, but is important in the care of the patient