Osteonecrosis Flashcards
What is it?
Ischaemic bone necrosis of all types
Ischaemia- bone marrow cells die within 12 hours followed by bone cells (osteoblasts etc.) in 12-24hrs
What are the different types of osteonecrosis?
Osteonecrosis of long bones
- bone infarction
- involves trabecular bone and bone marrow in medulla
- cortex has different blood supply
Osteonecrosis in the epiphysis
- called avascular necrosis
- can involve cortex also
What are the causes?
Interrupted arterial supply e.g. fractures
Interrupted venous drainage and retrograde arterial stoppage e.g. thrombosis
What are the risk factors?
Fracture e.g. NOF/Scaphoid Idiopathic e.g. Perthe's disease Bone marrow infiltration e.g. malignancy Alcohol abuse Cushings/exogenous steroid/chemo Infection e.g.SA
Which bones are commonly affected?
Head of femur
Proximal scaphoid
Lunate
Body of talus
What are the symptoms?
Well advanced at presentation Pain Stiffness Swelling In a joint but can be over bone
What are the investigations?
XR
- Sclerosis
- Flattening
- Subchondral radiolucent lines- crescent sign
- Collapse of cortex
Can take 6 months for changes to show
MRI can show earlier
What is the treatment?
Treat underlying cause
Prevent complications- stop fracture by weight relief or splint
Surgery where needed