Trauma, Fractures in Elderly, Sports Medicine Flashcards
(123 cards)
Skeletal bone is an _____
organ; tissues turn over by osteoclastic and osteoblastic activity
What is the structure of the bone
cortical (compact) bone & cancellous (trabecular) bone
Describe the cortical (compact) bone
80%; closely packed osteons, 5-30% porosity, diaphyseal (shaft), strong, resistant to bending
Describe the cancellous (trabecular) bone
network of plates & rods; trabeculae follow lines of stress ; metaphyseal (near ends); porosity 30-90%, 10% of cortical bone strength
what is an osteoblast
cells that form new bone; mesenchymal origin
what is an osteocyte
osteoblast embedded within the matrix it secretes; maintain bone and cellular matrix
what is an osteoclast
large cells that dissolve bone
what is bone extracellular matrix made of?
organic matter (20-25%), flexibility and resilience with type 1 collagen; inorganic matter (60-70%), hardness and rigidity with crystals of calcium, phosphate, hydroxyapatite
what is the function of bone ECM?
gene expression, tissue development, scaffold, regulate bone cell behaviour
bone is strongest in _____ and weaker in ______
bone is strongest in compression and weaker in tension (pulling bone apart)
where does the inner 2/3 of bone blood supply arise from?
endosteal
where does the outer 1/3 of bone blood supply arise from?
periosteal
what is the mechanical bone function?
load bearing, leverage, protect organs, locomotion
what is the biological bone function?
calcium homeostasis –> end organ for hormones (PTH, calcitonin, GH, corticosteroids)
what is the callus a response to?
living bone reaction to inter-fragmentary movement
describe the four stages of fracture healing
inflammatory
soft callus
hard callus
remodelling
describe primary bone healing
DIRECT OSTEONAL REMODELING
absolute stability, anatomic reduction & inter-fragmentary compression, no callus formation, healing via cutting cones & lamellar bone formation
describe secondary bone healing
relative stability, less stable fixation or non-surgical management, callus formation
what are the three factors that affect fracture healing?
soft tissue –> BLOOD SUPPLY
fracture biology
fracture stability
how is osteomalacia and fracture related
vitamin D deficiency –> reduced bone mineralization –> softening of bones
describe metabolic bone abnormalities
osteoporosis: quantitative bone loss
gastric bypass: calcium absorption affected
diabetes: affect repair and remodelling of bone
HIV: higher prevalence of fragility fractures, delayed healing
systemic inflammation: rheumatoid arthritis, polytrauma
cost of trauma is
4x cancer, 6x heart disease, leading cause of death/disability worldwide
age and sex of drivers involved in casualty collisions (most predominant) is:
18-24 males
alcohol role in fatal collisions:
16.3% of drivers involved in fatal collisions consumed alcohol prior to crash compared to 3.2% in injury collisions