Fracture Healing

Question 1

What is a fracture?

Answer 1

Any structural break in continuity of bone

Fractures are accompanied by significant soft
tissue injury

Soft tissue injury determines severity of injury and speed of rehabilitation

Question 2

Bone Biomechanics

Answer 2

Bone mineral (hydroxyapatite) strongest in compression - where the calcium is

Bone matrix (collagen) strongest in tension

Question 3

Open and Closed Fractures

Answer 3

Open fracture:
Any break in the skin that extends down to
bone
Much higher infection risk
More soft tissue damage, takes longer to heal

Closed fracture:
Skin is intact
Less infection risk, less soft tissue damage

Question 4

Description: Displacement

Answer 4

Undisplaced:
Buckle, hairline
Impacted

Displaced:
Lateral shift (percentage)
Angulation
Lengthening or shortening

Question 5

Pediatric Fractures: Salter–Harris Classification

Answer 5

Type I: fracture through growth plate
Type II: fracture exits through metaphysis
Type III: fracture exits through epiphysis (intra- articular)
Type IV: transverse, across growth plate (intra-articular)

Question 6

Fracture Healing Stages

Answer 6

Inflammation
Soft callus
Hard callus
Remodeling

Question 7

Inflammatory Stage

Answer 7

Lasts 1–3 days
Clinically: pain swelling and heat
Fracture hematoma clots at fracture site
Inflammatory cells migrate into region

Question 8

Soft Callus Stage

Answer 8

Early stage
Clinically stability is poor
Osteogenic “repair cells” from periosteum infiltrate hematoma
Chondroblasts form cartilage callus fracture site
becomes “sticky”
Osteogenic cells differentiate into osteoblasts
Cartilage callus is converted into woven type bone
Callus becomes evidenton X-ray at end of stage

Question 9

Hard Callus Stage

Answer 9

Clinical union (about 6–12 weeks)
Clinically fracture site no longer moves
Cartilage is replaced by woven bone
Callus is well developed on X-ray

Question 10

Remodeling Phase

Answer 10

Proceeds for years
Wolff’s law:
Bone responds to stress, becoming stronger
Osteoblasts lay down new bone along lines of stress
Osteoclasts resorb poorly located bone

Question 11

Factors That Affect Healing: Age

Answer 11

Children heal much quicker
Adolescents to older adults heal similarly
Elderly only heal slower when malnourished or when they have medical conditions

Question 12

Factors That Affect Healing: Site and Configuration

Answer 12

Metaphyseal bone heals faster than diaphyseal
(Better blood supply)
Comminuted fractures heal slower (> soft tissue injury, compromised blood supply to fragments)
Pediatric growth plate injuries heal in half the time (cellular machinery “geared up” for healing)

Question 13

Factors That Affect Healing: Initial Displacement

Answer 13

More displaced heals slower
More soft tissue damage
More vascular disruption

Question 14

Factors That Affect Healing: Blood Supply

Answer 14

Fractures need good blood supply to heal
Scaphoid in wrist has poor blood supply
Tibia is subcutaneous, not surrounded by muscle, and has a poorer blood supply
Vascular injuries or disease can affect
healing.

Question 15

Closed Reduction

Answer 15

Displaced fractures need to be reduced (straightened)

If stable after reduction, then cast immobilization
If unstable after reduction, then percutaneous or external fixation

Question 16

Open Reduction

Answer 16

Fractures that cannot be reduced closed need to be surgically opened

Bones can be directly manipulated and aligned

Internal fixation (plates and screws) is used to hold fracture

Question 17

Common Fractures

Answer 17

Proximal humerus (surgical neck)
Distal radius (Colles)
Scaphoid (navicular)
Hip
Femur
Tibia
Ankle

Question 18

Complications in fractures

Answer 18

Malunion
Nonunion
Infection
Compartment syndrome
Complex regional pain syndrome - Reflex sympathetic dystrophy (RSD)

Question 19

Malunion

Answer 19

Fracture heals normally
Unacceptable alignment

Question 20

Nonunion

Answer 20

Fracture does not show any sign of healing by three months
Need to stimulate bone to heal
Electrical stimulator
Bone grafting
Improved immobilization

Question 21

Infection

Answer 21

Possible after any surgical procedure
More common with open fractures
More common with diabetes

Question 22

Compartment Syndrome

Answer 22

Vascular compromise caused by extreme swelling
Tissue pressure becomes higher than venous pressure
Blood can get in, but can’t get out: circulation is blocked
Muscle compartment becomes ischemic and muscle dies

Question 23

Complex Regional Pain Syndrome

Answer 23

Pain, swelling, and autonomic dysfunction are hallmarks

Early: constant burning, aching, pain out of proportion to injury; edema can rapidly lead to joint stiffness
Middle: cold, glossy skin with decreased ROM
Late: atrophy and contractures

Stage 1: 3-6 months
Stage 2: 3-6 months
Stage 3: may last years