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Avascular necrosis of the femoral head - AVN.
Osteonecrosis, also known as aseptic necrosis, avascular necrosis (AVN), atraumatic necrosis, and ischemic necrosis.
Osteonecrosis of the hip occurs in the femoral head.
it is a painful condition that occurs when the blood supply to the head of the femur is disrupted.
This typically leads to death of the bone cells in a localized area of the femoral head
leading to collapse of the necrotic segment of the head.
As a result, the articular cartilage covering the hip bones also collapses, leading to disabling arthritis within a few months to 2 years.
there are two types of osteonecrosis are limited to children:
idiopathic osteonecrosis of the femoral head (Perthes disease)
and osteonecrosis occurring in children, usually adolescents, with a slipped capital femoral epiphysis.
osteonecrosis of the hip develops in stages and early on there are often no symptoms
As the condition progresses and there are bone changes,
most patients will experience pain which is usually felt in the groin area
but may radiate into the thigh or very occasionally into the buttock.
Eventually, the hip is often painful at rest,
movement is restricted and activity is severely limited.
Imaging studies will help your doctor confirm the diagnosis.
On X-ray, a thin, curvilinear lucent line parallel to the cortical margin of the femoral head, in a patient with AN.
it is the crescent sign, an evidence of subchondral collapse.
Later stages reveal loss of sphericity or collapse of the femoral head.
Ultimately, joint space narrowing and degenerative changes in the acetabulum are visible.
Treatment:
For patients with a small lesion (involving less than15 % of the femoral head),
we suggest nonsurgical treatment rather than surgery.
For patients with medium lesions (involving 15 to 30 percent of the femoral head),
we suggest core decompression (with or without grafting) or bone grafting rather than supportive therapy.
Core Decompression
vascularized or free fibula graft.
Large-sized lesions (involving greater than 30 % of the femoral head) that are pre-collapse,
We suggest not using a core decompression and grafting,
highly likely to progress to collapse and may need to undergo total hip arthroplasty.
For symptomatic early lesions with less than 2 mm of depression,
we suggest vascularized or non-vascularized bone grafting as I've already said.
rotational Osteotomy can be used in younger patients with for patients with a small lesion (less than 15 %) and with minimal collapse.
If osteonecrosis has advanced to the point where the femoral head has already collapsed, the most successful treatment is total hip replacement.