Fractures and Bone Healing

Question 1

Who are fractures more common in?

Answer 1

• men up to 45
• women over 45
• before 75 = wrist fractures -> Colles and Colles like

Question 2

What is the difference between a Colles fracture and a Colles like fracture?

Answer 2

• Colles = fracture of distal radius

- Colles like = ulnar fracture as well

Question 3

What are the 3 broad types of fractures?

Answer 3

• closed (bone fragments do not pierce skin, nerves and vessels may still be hurt)
• open/compound (bone fragments pierce skin, bacteria and pathogens may enter)
• displaced or undisplaced

Question 4

What are transverse fractures?

Answer 4

• directly applied force to fracture site

- break goes right across bone

Question 5

What is a spiral/oblique fracture?

Answer 5

• violence transmitted through limb from a distance (twisting movements)
• e.g. 1 end of limb fixed and proximal twisted
• x-ray view required as fracture may extend up and around bone

Question 6

What is a crush/compression fracture?

Answer 6

• axial skeleton common in osteoporosis

- trabecular bone weakened and fractures due to body weight

Question 7

What are the causes of crush fractures?

Answer 7

30-80 years

- decrease in toughness, strength and elasticity of trabecular bone

Question 8

What is a burst fracture?

Answer 8

• at thoracic lumbar junction

- in short bones (vertebra)

Question 9

How can a fall end in a burst fracture?

Answer 9

• due to fall and land on feet, force directed through pelvis into column, vertebra squashed between IV discs, burst open and trabecular bits break off, pedicles and lamina made of cortical bone not impacted
• pieces impinge nerve roots

Question 10

What is an avulsion fracture?

Answer 10

• tendon/ligament inserting into bone tears off taking bone fragment with it
• caused by traction
• internal fixation/screw to put attachment back on

Question 11

What is a dislocation/subluxation?

Answer 11

• fracture involving a joint

- get malalignment of joint surfaces

Question 12

What is an impacted fracture?

Answer 12

• bone fragments impacted/forced into each other
• difficult to see on x-ray
• often only requires splinting

Question 13

What is a comminuted fracture?

Answer 13

• 2 or more bone pieces involved
• high energy trauma
• disruptive to blood supply
• long time to heal
• difficult to put pieces back together

Question 14

What is a stress fracture?

Answer 14

• fatigue (abnormal stress on normal bone) or insufficiency fractures (normal stress of abnormal bone)
• happening inside bone so difficult to see on x-ray
• periosteal reaction (marker of osteoblast differentiation)

Question 15

What is a torus fracture?

Answer 15

• common in children
• softer bones = axial load causes trabecular compression, one side of bone bulges
• indentation underneath
• quickly heals

Question 16

What is a greenstick fracture?

Answer 16

• children
• soft bones
• bend without fracturing properly

Question 17

How do you get fractures of the epiphyseal growth plate?

Answer 17

• EGP of ulnar can cause EGP to close prematurely so interferes with growth
• radial distal joint = EGP stops growing but does not stop at elbow and ulnar does not stop

Question 18

What is a fracture hematoma?

Answer 18

• blood from broken vessels = clot
• hypoxia and low pH
• pro-inflammatory cytokines and anti-inflammatory cytokines from peripheral blood
• immune cells recruited to injury site
• 6-8 hours after injury
• swelling and inflammation to dead bone cells

Question 19

What is a fibrocartilaginous callus?

Answer 19

• lasts 3 weeks
• procallus (new capillaries organise fracture haematoma into granulation tissue, fibroblasts and osteogenic cells invade, differentiate into chondrocytes/osteocytes)
• make collagen fibres
• chondroblasts begin to produce fibrocartilage

Question 20

What is a bony callus?

Answer 20

• after 3 weeks
• lasts 3-4 months
• osteoblasts make woven bone

Question 21

What is bone remodelling?

Answer 21

osteoclasts remodel woven bone (compact and trabecular)