Bone Growth and Fractures Flashcards
cessation of bone growth
- 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
what are the areas of growth in the epiphyseal plate
ossification one calcification one hypertrophic zone growth (proliferation) zone resting zone
Pathological defects in epiphyseal plates: resting zone
- Matrix production
- diastrophic dwarfism
- defective collagen synthesis/processing of proteoglycans
Pathological defects in epiphyseal plates: growth zone
- cell proliferation
- achondroplasia, malnutrition, irradiation injury, gigantism
- deficiency in cell proliferation and/or matrix synthesis
- gigantism is an increase in cell proliferation
Pathological defects in epiphyseal plates: hypertrophic
- calcification of the matrix
- rickets, osteomalacia
- insufficiency of calcium or phosphate fr normal calcification
Pathological defects in epiphyseal plates: metaphysis
- bone formation and vascularisation
- osteomyelitis = bacterial infection
- osteogenesis imperfecta = abnormality of osteoblasts and collagen synthesis
- scurvy = inadequate collagen turn over
Normal growth and development of bone requires:
- calcium
- phosphorus
- vitamins A and D
- balance between growth hormone, thyroid and parathyroid hormones, oestrogen and androgens
Clues on energy transfer on an X-ray
wide displacement
comminuted
multiple fracture sites
what is the definition of a fracture
a complete or incomplete break in a bone
Avulsion fracture
– a fragment of bone is separated from the main mass
Buckled fracture
- impacted fracture, torus fracture
- ends are driven into each other
- commonly seen in arm fractures in children
compression or wedge fracture
usually involves the vertebra
pathologic fracture
caused by a disease that weakens the bones
stress fracture
hairline fracture
Limb threatening or non-union risk
– Dislocation – Comminuted – Compound – Compartment syndrome – Vascular / nerve injury – Significant soft issue injury – Pathological bone
Bone healing following a fracture
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
first phase of fracture healing
reactive phase:
- fracture and inflammatory phase (haematoma)
- fibroblasts in the periosteum proliferate to form granulation tissue around the fracture site
stage 2 phase of fracture healing
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
stage 3 phase of fracture healing
remodelling phase:
- remodelling by osteoclasts to restore original bone shape
conservative treatment
– Simple fracture with low risk of non-union
– Dependent on natural healing process
– +/- immobilisation
– Rehabilitation
intervention treatment
– Fractures with limb threat or risk of non union
– Augment natural healing with replacement or strengthening
– +/- immobilisation
– Rehabilitation
