basic science Flashcards
what is osteonecrosis ?
reduced vascular supply to the bone resulting in progressive and painful degeneration of the bone
what are the common sites of traumatic osteonecrosis ?
hip
scaphoid
talus
usually what is the manageement of extrracapsular fractures ?
fixation
what is the usual management for intracapsular fractures ?
fixation in selected cases
arthroplasty
what are the non traumatic causes of osteonecrosis ?
infection
sickle cell disease
gaucher disease
coagulation disorders
alcohol abuse
what are the clinical features of osteonecrosis ?
earliest stage of bone death is asymptomatic
pain is usually the complaint
clicking
what is seen on imaging in cases of osteonecrosis ?
x ray may be normal in early disease
crescent sign
what is the gold standard imaging for osteonecrosis ?
MRI
what are the two treatment options for osteonecrosis ?
either conservative - bed rest, treat underlying cause
or surgical - core decompression, osteotomy, replacement
what are the two type of bone healing ?
primary bone healing - healing by direct union
secondary bone healing - healing by callus formation
what are the 5 stages associated with secondary healing ?
hematoma formation
inflammation
soft callus ( woven bone )
hard callus (lamellar bone )
remodelling
what are the possible outcomes after a fracture ?
1- union : includes clinical and radiological
2- delayed union : slower than expected
3- non-union : no healing after 2 times the amount needed to heal
4- Mal-union : non anatomical position
what are the types of non union ?
hypertrophic - calluses and good blood supply
atrophic - no calluses , poor blood supply
infected
what do the different types of non union require for treatment ?
hypertrophic - needs stabilization
atrophic - needs biological enhancement through bone graft
what are the forces acting on the hip joint ?
abductor force
body weight
load on joint
