ICL 8.4: Fractures & Dislocations Flashcards
what is a closed vs. open fracture?
closed = skin is intact; no risk for infection (:
open = skin is not intact; somewhere the bone popped through the skin
what are the types of open fractures?
grade 1-3
grade 1 = <1 cm, not a big puncture
grade 2 = 2-10 cm wound
grade 3 = giant wounds bigger than 10 cm; high energy accident like motorcycle or farm machinery
A = adequate soft tissue coverage
B = requires flap coverage; some muscle and skin is missing and you can’t get the bone covered
C. = associated vascular injury; you start thinking about amputation off the bat
what is the terminology used to describe the location of a fracture?
- diaphyseal = mid-shaft
- metaphyseal = near the joint but not involving it
- epiphyseal = right at the joint level
why is important to know if the joint is involved in a fracture?
the joints are where you move and you want to get the bone back together as close as possible
so if there’s a gap in the bone at a joint surface more than 2 mm, your chances of getting arthritis go up a TON
what is a simple fracture?
the bone just snapped in half; clean break not a lot of pieces
lower energy injury
what is a comminuted fracture?
multiple fragments of bone so it will be harder to fix and inherently unstable
you probably need surgery to fix…
usually due to higher energy injuries (which is why the bone got shattered into many pieces) –> all the energy gets dissipated through the muscle and skin around it which will effect the nerves and arteries in the area too so everything gets messed up
what is angulation in relation to a fracture?
is the bone straight?
varus = bent inward towards midline (angle faces the midline)
ex. bowlegged
valgus = bent outward away from the body
ex. knock kneed
what is displacement in relation to a fracture?
are the two ends of the bone still touching?
what do you doing during a PE of a fracture?
- soft tissue condition
- pulses present?
- sensation?
- motor function?
what are the different ways you can evaluate fractures?
- radiographs
initial study, cheap, adequate 99% of the time
- CT
greater detail of fragmentation; usually for fractures around joints
- MRI
you can see bone bruises, stress fractures, bone vascularity
what is a Salter Harris fracture?
pediatric fractures involving the growth plate –> growth plate is the weakest part of the bone
kids bones are softer and will sometimes bend and not actually break
I = through the growth plate
II = metaphyseal extension (most common)
III = epiphyseal fragment
IV = metaphysis and epiphysis
V = crush injury (the worst)
SALTER = straight across, above, lower, through, erasure of growth plate (crush)
what 3 types of vessels supply blood to bones?
- nutrient arteries = in the middle of the bone, go into the intramedullary canal and run the length of the bone
- epiiphyseal/metaphyseal vessels
- periosteal vessels
what is a nutrient artery?
main blood supply of the diaphyseal cortex = the thick hard part of the outside of the bone
they enter the bone at the nutrient foramen
they form a network of arteries
what are periosteal vessels?
they supply 20% of the diaphyseal cortex = the thick hard part of the outside of the bone
what are epiiphyseal/metaphyseal vessels?
they supply blood to the actual joint surface of the bone
what are the stages of fracture healing?
- hematoma
- inflammation
- repair
- remodeling
what happens during the inflammation phase of fracture healing?
this is the first stage after fracture
and involves large hematoma formation (1st week)
macrophages, neutrophils, platelets release cytokines =
PDGF, TNF-Alpha, TGF-B, interleukins
which promote angiogenesis and vasodilation
then mesenchymal cells migrate to fracture site and differentiate and proliferate into fibroblasts and osteoblasts –> COX-2 important in this cascade (NSAIDs)
why does taking NSAIDs after a bone fracture complicate the healing process?
COX-2 is important in inflammatory cascade
so if you take NSAIDs which are COS-2 inhibitors you might slow down the healing process a little
what happens during the repair phase of fracture healing?
fibroblasts and osteoblasts are present now so fibroblasts start forming scar tissue and the two ends of the bone start to get “sticky” and then eventually you start to get bone = callus
periosteal callus forms along the periphery of the fracture site
intramedullary callus forms
callus matures and begins to mineralize into woven bone (type II to type I collagen)
mechanical environment important in this process:
- stable = osteoblastic differentiation and primary cortical healing
- unstable = chondrocytic differentiation and endochondral ossification
what happens during the remodeling phase of fracture healing?
once you get a callus formed aka bone, you can start to remodel it (week 4 –> 1 year)
woven (immature) bone is gradually converted to lamellar (mature) bone –> your body is just making bone as fast as it can even if it’s not good bone or organized aka woven bone
medullary cavity is reconstituted
bone is restructured in response to stress and strain (Wolff’s Law)
what is primary bone healing?
aka direct healing
haversian or cutting cone remodeling
this ONLY happens if you do surgery on the bone
you DON’T see callus or the normal response to a fracture!
it’s fracture healing with no motion at the fracture site
what is secondary healing?
the way bones are supposed to heal via inflammation, formation, remodeling
over the course of the next year after the fracture, the bone will see stress and the callus will remodel into normal looking bone and the callus will disappear and the bone will look normal again
endochondral remodeling with cartilage precursor
what are the steps that happen during primary bone healing?
this is what happens all the time, every day; like if you decide to start going to the gym and now there’s extra stress on your bones
you will start to see formation of cutting cone that crosses fracture site = groups of cells that travel around the bone all day long
osteoclasts at the front of the cutting cone are breaking down bone and behind them are osteoblasts which are laying down lamellar bone behind osteoclasts
so during surgery, you put in screws so then there’s not a lot of movement around the fracture and your body doesn’t even realize it’s broken so this normal every day process with the osteoblasts and osteoclasts happens and you don’t get the big wad of callus like with secondary healing
when you get secondary bone healing, what was the type of treating done?
casts, splints, braces, traction
aka external fixation
what are the different types of fixation you can do for fracture?
- casts/splints
- external fixation
- intra-medullary nails
- plates and screws
what are intra-medullary nails used for?
lower extremity nails used for long bone fractures
what are external fixators used for?
usually used for open fractures
they are used as temporary stabilization for trauma patients
what are plates and screws used for?
fractures around joints
why do some broken bones need surgery?
- pain
- better outcomes from the bones healing more reliably and in better positions
- prevent arthritis
* most pediatric fractures can be managed without surgery
why can most pediatric fractures be managed without surgery?
fractures usually are in the growth plate which is going to heal really quickly
another reason is that the bone is growing so the bones will straighten themselves outs a result of normal pressure that gets put on them through daily activities
what are some complications associated with bone fractures?
- compartment syndrome
- fat emboli
- pulmonary embolism
- non-union
- mal-union
- infection
what is compartment syndrome?
your muscles are in fascial compartments and when you break your bone it’s like sticking a hotdog in a microwave and everything comes out of the casing –> it’s swelling inside the fascial compartment so the muscles start dying
swelling within the compartment impedes circulation which leads to necrosis of muscle and nerve tissue
compartment pressure is above 40 mm/Hg require emergent release (normally 5-10)
what are the 5 P’s of compartment syndrome used to diagnose?
pain***
pallor
paresthesia
pulselessness
paralysis
how do you treat compartment syndrome?
go in surgically and cut the fascia to release the pressure
what is a fat embolism?
fats from the intramedullary canal get into the venous blood stream after a fracture
you’ll see petechial hemorrhages
the bad part is when microdroplets of fat trapped in the lungs so people will get pneumonia
this usually doesn’t happen anymore because we fix fractures
what is a non-union?
a fracture that has not and will not go on to heal
3 types:
atrophic = no healing at all; vascularity prbobalem
oligotrophic = somewhere in the middle
hypertrophic = lots of callus but not healing because of stability problem; so bone is moving too much
what are risk factors for non-union?
- Open fractures
- High energy fractures with devitalization of bone
- Severe soft tissue injury
- Bone loss
- Infection
what is a dislocation?
when you pop a joint out of place and the joint is no longer lined up
all/most the ligaments are torn around the joint….
you need to check the arteries, nerves and soft tissues just like you would a fracture
what are some common dislocations?
- shoulder
- elbow
- hip
- knee
what are characteristics of shoulder dislocations?
most common major joint dislocation
usually anterior and inferior
the big problem with young patients = recurrent dislocations
the big problem with older patients = rotator cuff injury
what are characteristics of elbow dislocations?
usually sports dislocations so also 10-20 years old
ulnar nerve is there so check!
usually posterior and lateral
what are characteristics of hip dislocations?
almost always due to MVA
usually posterior dislocation
can result in avascular necrosis of the femoral head
what are characteristics of knee dislocations?
they’re really really bad because high association with vascular network in the back of your knee and lots of nerves there too that can get stretched out
luckily they’re not very common
which joint dislocation can be life threatening?
sternoclavicular
because if it pops backwards it can press down on your aorta
