Osteochondritis and Avascular necrosis Flashcards
what do these have in common
area of bone undergoes localized necrosis as a result of ischaemia from a reduction in blood supply
what is the pathogenesis of osteochondritis?
recurrent impact/traction injuries - bleeding and oedema in the bone - capillary compression - bone necrosis ensues - compression, fragmentation or separation of bone and overlying cartilage if intra-articular - flattening and incongruence of a joint or a pothole on the surface
Who gets osteochondritis?
children and young adults
increased physical activity with repetitive stress - compression/ traction
familial predisposition
underlying coagulopathy
common sites affected by compression
2nd metatarsal head - Freiburg’s disease
navicular bone - Kohler’s disease
lunate of the carpus - Kienbock’s disease
capitulum of the elbow - Panner’s disease
vertebral compression - Scheurmann’s disease
hip - Perthes disease
aopohysis (bony tubercle where tendon attaches) - traction osteochondritis
- tibial tubercle - Osgood Schlatter disease
- calcaneous - Sever’s disease
- (self limiting and settles with rest)
development of osteochondritis
pain
progression to arthritis at a young age if a joint is involved
Osteochondritis dissecans
fragmentation with separation of bone and cartilage within a joint
lateral part of medial femoral condyle in knee anteromedial tala dome superomedial femoral head humeral capitellum - pain and effusions & locking
how is osteochondritis managed?
compression types of osteochondritis may settle
restriction of activities
splintage may help in wrist/ foot
arthritis in affected/ neighbouring joints can occur
if joint damaged - osteotomy (surgical bone realignment) shift load in a joint to undamaged area
osteochondritis dissecans - pinning unstable fragments/ removal of detached fragment
what is a vascular necrosis?
ischaemic necrosis of bone predominantly in adults
areas prone to avascular necrosis (AVN)?
femoral head femoral condyles head of humerus capitellum proximal pole of the scaphoid proximal part of talus
what is AVN commonly secondary to?
fracture of femoral neck proximal humerus waist of scaphoid and talar neck many are idiopathic - no known cause
Other causes of AVN?
alcoholism, steroid abuse (alter fat metabolism - mobilisation of fat into circulation - sludge up capillary system and promote coagulation - increased fat content of the marrow can compress venous outflow from the bone - stasis and ischaemia)
primary hyperlipidaemia
thromophilia
sickle cell disease
antiphospholipid deficiency in SLE
Caisson’s disease/ decompression sickness - Nitrogen gas bubbles (deep sea diving)
what are the consequences of AVN?
necrosis of a segment of bone patchy sclerosis subchondral collapse irregularity of the articular surface secondary osteoarthritis
secondary affects of AVN on osteoarthritis joints
collapse of articular surface
rapid deterioration
AVN first - secondary OA
OA first - complicated by AVN
how is AVN treated?
early - can be seen on MRI before any radiographic changes occur
articular surface not collapsed in an amenable site - drilling under fluoroscopy to
- decompress the bone
- prevent further necrosis
- help healing
articular surface collapsed - joint replacement (hip, knee, shoulder)
wrist/foot/ankle - fusion
