Dr Beaver's tute - avascular necrosis and osteonecrosis Flashcards
avascular necrosis
acute interruption by trauma of the blood supply
osteonecrosis
interruption of blood supply by some sort of metabolic process
loss of blood supply to femoral head in a growing child not due to trauma
as a growing child - perthes disease
both avascular necrosis and osteonecrosis lead to
dead bone
loss of blood supply to femoral head post trauma is
avascular necrosis
how can you tell dead bone on an x-ray
the dense area
bone atrophies - bone mineral should be sapped out
osteoclasts do this
osteoclasts require blood supply which is not present
so the bone becomes dense because it can’t be removed by osteoclasts because there’s no blood
how does cartilage get nutrition
synovial fluid
why does cartilage survive
because loss of blood supply it ok because it doesn’t get nutrient directly form blood it gets it from synovial fluid
who gets osteonecrosis
steroids
bisphosphonates (cause osteonecrosis of the jaw and femur)
CKD
alcoholism/smoking/diabetes
dysbarism (change in pressure eg. scuba divers)
immune suppression
irradiation
idiopathic
acute complications of fracture
acute compartment sydndrome
neurovascular injury
fracture blisters
wound infections
osteomyelitis
secondary dislocation
complications due to immobilisation
thrombosis
infections eg. pneumonia, urinary tract infection
compromised fracture healing
nonunion: incomplete healing
growth disturbnce eg. fter growth plate fracture in children
post traumatic osteoarthritis
complex regional pain syndrome
joint stiffness/contracture
joint instability
heterotopic ossification
risk factors for non-union
poor vascular uspply
inaddequate immobilsation
chronic disease eg. diabetes, osteoporosis
open fractures
infection
smoking
