Bone Health Flashcards
(38 cards)
What are the causes of fracture?
- Single traumatic event
- Repetitive stress
- Pathological - abnormal weakness in bone
What are open/closed fractures?
open breaks skin, closed doesn’t
What are comminuted/simple fractures?
comminuted = break or splinter of bone into 2+ fragments simple = fracture of bone only, no damage surrounding tissues
What is bone made up of?
Cells + ECM
Matrix:
- organic components (collagen = tensile strength)
- inorganic components (minerals = compressive strength)
What are Haversian canals?
Tubes which form network in cortical bone - allow BV’s + nerves to travel through.
Surrounded by lamellae.
What are the main 2 stages of bone formation?
- Osteoblasts deposit osteoid
- Osteoid is mineralised (apatite incorporated into bone)
10 days between deposit + mineralisation
What are the main 2 stages of bone remodelling?
- Osteoclast resorption
2. Osteoblast deposit new bone
Summarise what happens in fracture repair
Cell proliferation + tissue differentiation
What are the stages of bone healing?
- Haematoma
- Inflammation
- Granulation
- Callus
- Consolidation
- Remodelling
Describe the haematoma stage of bone healing
- BV tearing
- Local bleeding
- Defect between fracture ends filled with blood clot
Describe the inflammation stage of bone healing
- acute
- macrophages invade clot + destruct
- followed by vascular growth
Describe the granulation stage of bone healing
- vascular ingrowth
- day 5: granulation tissue replaced clot
- groups of cartilage cells form in granulation tissue
Describe the callus stage of bone healing
- cartilage islands
- fracture ends united by vascularised granulation tissue + cartilage = provisional callus
By end of week 1:
- Ca deposited in cartilage
- osteoblasts produce osteoid across fracture
- endochondal ossification established + adds to new bone
- callus calcifies + ends unite with bony callus
Describe the remodelling stage of bone healing
- woven bone (immature) replaced by lamellar (osteoblasts + osteoclasts)
- excess bone resorbed
- takes years, often incomplete
Define osteoporosis
Metabolic bone disorder characterised by low bone mass + microstructure deterioration in bone tissue = increased bone fragility = increasing fracture risk
What are the 2 types of osteoporosis?
- Primary = post menopausal or age related
- Secondary = drug related/comorbidities
How is osteoporosis diagnosed?
- DEXA bone density scan - measured in spine + hip
- Underestimates
- Osteoporosis: If T score less than or equal to -2.5 SD
Fragility fracture whatever the T-score - Osteopenia: T score -1 - -2.5 SD
What are the risk factors associated with osteoporosis?
Female, >50y, no children, post-menopausal, early menopause, caucasian/asian, sedentary lifestyle, slim, alcohol, smoking, thyroid, hypogonadism, PPI’s
What are the effects of oestrogen in osteoporosis?
- Low levels = increase in osteoclast : osteoblast
- Low levels = apoptosis of osteoblast
What are the signs of osteoporosis?
- Shorter than they were
- Skeletal tenderness
- Kyphosis
- Hump
- Unsteady
- Plaster
What tests are done in osteoporosis?
- XR if fracture
- DEXA
- FBC
- Bone profile
- Renal test
- LFT
- Thyroid function test
Blood tests = NORMAL in IDIOPATHIC osteoporosis
Define an osteoporotic fracture
Fragility fracture caused by force which would not normally break bone
What is the strongest predictor of osteoporosis?
Previous fracture
What is the primary prevention of osteoporosis?
For post-menopausal without fracture
- Weightbearing + strengthening exercise
- Stop smoking
- Reduce alcohol
- Healthy diet
- Ca + Vit. D
