avascular necrosis Flashcards
1
Q
what is avascular necrosis
A
failure of blood supply to the femoral head
2
Q
results of avascular necrosis
A
ischameic necrosis of bone and marrow
3
Q
causes for idiopathic AVN
A
- Coagulation of the intraosseous microcirculation
- Venous thrombosis causes retrograde arterial occlusion
- Intraosseous hypertension
- Decreased blood flow results in necrosis of a segment of bone
- There will be patchy sclerosis before subchondral collapse and irregularity of the articular surface occurs
- Resultant bone and joint damage can lead to significant structural collapse of the bone → secondary OA
- Can also secondarily affect osteoarthritic joints causing collapse of the articular surface and rapid deterioration
4
Q
risk factors for AVN
A
irradiation
hematologic diseases (leukemia, lymphoma), sickle cell or hypercoagulable staes
dysbaric disorders (decompression sickness, “the bends”) - Caisson disease
alcoholism
steroid use
trauma
5
Q
patient presentation
A
Insidious onset of groin pain
Exacerbated by stairs or impact
Examination is usually normal unless disease has advanced to collapse/OA
6
Q
how to diagose AVN
A
radiographs
MRI
7
Q
AVN associated with trauma
A
fracture disrupts the blood supply to an entire portion of bone
8
Q
reversible AVN management
A
- If the articular surface has not collapsed in an amenable site, AVN can be reversed
- Bisphosphates
- Core decompression - drilling performed under fluoroscopy to ‘decompress’ the bone to prevent further necrosis and help healing
- Curettage and bone grafting
- Vascularised fibular bone graft
9
Q
irreversible AVN management
A
- If the articular surface has collapsed, generally joint replacement is usually required in the hip, knee or shoulder to control symptoms
- Rotational osteotomy can be considered if less than 15% of femoral head damaged (rare)
- Fusion can be considered in the wrist or foot/ankle
10
Q
A
