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17 Cards in this Set
- Front
- Back
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cartilage |
compression, embryonic growth; think jello; watery AVASCULAR environs with proteoglycans and type II collagen arcs; NOT normally mineralized except at growth plate; chondrocytes maintain matrix; limited response to attack; adults= joint linings |
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bone |
tension and strength; think tree; 35% organic matrix (collagen type I) + 65% mineral (Ca, Mg, Na); LITTLE water; complex structural and tissue (mineral depot) demands; VASCULAR constant turnover (rapid growth, slow adult) |
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bone development (the names) |
woven bone comes first (not as strong) and then lamellar; lamellar can further be classified as either cortical (has blood vessels going through it for nutrients) or trabecular (aka cancellous aka spongy, thin and can get nutrients from the bone marrow (metaphyses are examples)); model for growth (versus lifelong remodel) (up to 25% trabecular, much less cortical at 3%) |
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bone as tissue (name the cell types and how they work) |
osteoblasts (vessels needed) (make bone); osteocytes (marooned osteoblasts with web of cancliculi); osteoclasts (resorption control, in howship lacuna) (break down bone) (they are from the macophage line of cells); type I collage; needs blood vessels; mineralized |
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bone versus other tissue repair |
other tissue= injury acute response (clean up), repair with granulation tissue, fibrosis and/or regeneration (SCAR); bone= injury acute response (clean up), repair is callus (OSTEOGENIC granulation tissue), reconstitute structure is union, perfection by remodeling |
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fractures: what makes a successful repair |
intact vasculature, stability, alignment, approximation, clean environs, normal metabolic state, age dependant |
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fractures: early complication |
compartment syndrome; local vessel and/or nerve damage; fat embolism (femur, rare) |
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fractures: late complications |
delayed or nonunion; secondary osteomyelitis; compromised vasculature; malalignment, large gap; pseudoarthrosis (the ends of the bones in the fracture confuse the body and they are turned into a joint i.e. the alcoholic with 2 joints in his arm) |
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bone necrosis |
traumatic (fracture); infection (septic necrosis, sequestrum); avascular (idiopathic necrosis); definition= absence of osteocytes in bone lacunae, necrosis adjacent marrow; repair by 'creeping substitution' of new bone around dead bone |
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fracture: bones at risk |
femoral head; distal tibia; scaphoid |
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avascular necrosis (AVN) |
sites= many often with eponyms; symptomatic commonly if subchondral, other sites may be silent; associations (many idiopathic)= dysbarism, gaucher disease, sickle cell anemia/hemoglobinopathies, alcoholism, cushing syndrome/prednisone use |
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osteomyelitis: where does it occur in children/adults, what causes it most of the time, what does it look like and what are the names of its components |
children= metaphysis long bones, complication is DVT, STAPHYLOCOCCUS AUREUS most common; adults= vertebral column more common, complication is cord compression, STAPH AUREUS is still #1, gram negatives more common; a dead piece of bone sitting in the middle of pus= a SEQUESTRUM (basically septic infarction) (this is a buzz word for osteomyelitits); the bone formed around the sequestrum to try to wall it off= INVOLUCRUM (really all it is is the periosteum); CODMAN'S TRIANGLE= if the periosteum lifts up fast to cover the sequestrum so it looks like it's flapping in the wind with no new formed bone under it; codman's triangle can happen with infection or with a neoplasm that is eating the bone and making the bone try to make more bone; obviously it is extremely difficult to treat an infection that is walled off by bone; happens often in the spine and starts as an infection of the disc before spreading to the bone and eating it |
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osteomyelitis: secondary |
compound fractures with large soft tissue defects (its broken through the skin so infection possible); internal and external fixation (you've put a pin in to hold the bone so you've broken the skin); poor blood supply, pre existing/injury (diabetes, peripheral vascular disease); organisms overall= S aureus, staphylococcal spp, anaerobes (often mixed) |
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osteomyelitis: special groups |
REMEMBER staphylococcus aureus most common overall; healthy neonates= joint often involved, enterobacter, group A and B streptococcus; older children= group A strep, H influenza in past (vaccine now available), enterobacter; high risk neonates (NICU)= often multifocal bones, S aureus, E coli; IV drug abusers= pseudomonas spp, serratia, others; sickle cell anemia= diaphyses long bones, salmonella spp; foot punctures (step on nail)= >15%, pseudomonas spp, as well as staph |
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osteomyelitis: special groups (cont) |
secondary osteomyelitis (break the skin/local trauma)= fight bites (mixed, mouth anaerobes), dog and cat bites (pasteurella multicida), S aureus still most common even in these groups, often mixed organisms including anaerobes; BEWARE even the best cultures only positive 50-75% of the time |
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bugs: osteomyelitis versus infectious arthritis |
bone= S aureus, IV drug is pseudomonas spp, TB; joint= S aureus, N gonorrheae, lyme disease, IV drug is pseudomonas spp, TB, virus (HB, parvo, rubella); REMEMBER THAT TB CAN INFECT BOTH JOINTS AND BONE |
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TB: bones and joints |
evidence of active or old pulmonary disease may NOT be present (they didn't know that they had it and it stuck around to strike when you are weak); indolent granulomatous inflammation; classic lesion= pott disease of spine with GIBBUS (aka a collapse of a vertebral body secondary to the TB infection eating the bone), psoas abscess; knees and hips next most common; BEWARE high index of suspicion needed; central caseous necrosis (red is dead) and peripheral epithelioid histiocytes and lymphocytes |
