Bone Growth and Fractures

Question 1

cessation of bone growth

Answer 1

• growth in height ceases at the end of puberty
• sex steroids stimulate growth spurt but promote closure of epiphyseal plates
• growth in length ceases, cell proliferation slows and plate thins
  the plate is then invaded by blood vessels, epiphyseal and diaphysial vessels unite

Question 2

what are the areas of growth in the epiphyseal plate

Answer 2

ossification one 
calcification one 
hypertrophic zone 
growth (proliferation) zone 
resting zone

Question 3

Pathological defects in epiphyseal plates: resting zone

Answer 3

• Matrix production
• diastrophic dwarfism
• defective collagen synthesis/processing of proteoglycans

Question 4

Pathological defects in epiphyseal plates: growth zone

Answer 4

• cell proliferation
• achondroplasia, malnutrition, irradiation injury, gigantism
• deficiency in cell proliferation and/or matrix synthesis
• gigantism is an increase in cell proliferation

Question 5

Pathological defects in epiphyseal plates: hypertrophic

Answer 5

• calcification of the matrix
• rickets, osteomalacia
• insufficiency of calcium or phosphate fr normal calcification

Question 6

Pathological defects in epiphyseal plates: metaphysis

Answer 6

• bone formation and vascularisation
• osteomyelitis = bacterial infection
• osteogenesis imperfecta = abnormality of osteoblasts and collagen synthesis
• scurvy = inadequate collagen turn over

Question 7

Normal growth and development of bone requires:

Answer 7

• calcium
• phosphorus
• vitamins A and D
• balance between growth hormone, thyroid and parathyroid hormones, oestrogen and androgens

Question 8

Clues on energy transfer on an X-ray

Answer 8

wide displacement
comminuted
multiple fracture sites

Question 9

what is the definition of a fracture

Answer 9

a complete or incomplete break in a bone

Question 10

Avulsion fracture

Answer 10

– a fragment of bone is separated from the main mass

Question 11

Buckled fracture

Answer 11

• impacted fracture, torus fracture
• ends are driven into each other
• commonly seen in arm fractures in children

Question 12

compression or wedge fracture

Answer 12

usually involves the vertebra

Question 13

pathologic fracture

Answer 13

caused by a disease that weakens the bones

Question 14

stress fracture

Answer 14

hairline fracture

Question 15

Limb threatening or non-union risk

Answer 15

– Dislocation
– Comminuted
– Compound
– Compartment syndrome
– Vascular / nerve injury
– Significant soft issue injury – Pathological bone

Question 16

Bone healing following a fracture

Answer 16

Fracture healing depends on the activity of osteoblasts in the local periosteum

Takes 2 -20 weeks for healing, depending on: – Severity and position of the fracture
– Age of the patient

Question 17

first phase of fracture healing

Answer 17

reactive phase:

• fracture and inflammatory phase (haematoma)
• fibroblasts in the periosteum proliferate to form granulation tissue around the fracture site

Question 18

stage 2 phase of fracture healing

Answer 18

reparative phase:

• callus formation: osteoblasts quickly form woven bone, to bridge the gap
• woven bone: is weak as the collagen fibres are arranged irregularly
• lamellar bone: laid down, collagen organised in regular sheets to give strength and resilience

Question 19

stage 3 phase of fracture healing

Answer 19

remodelling phase:

- remodelling by osteoclasts to restore original bone shape

Question 20

conservative treatment

Answer 20

– Simple fracture with low risk of non-union
– Dependent on natural healing process
– +/- immobilisation
– Rehabilitation

Question 21

intervention treatment

Answer 21

– Fractures with limb threat or risk of non union
– Augment natural healing with replacement or strengthening
– +/- immobilisation
– Rehabilitation