Avascular necrosis of the hip is death of bone in the femoral head because its blood supply is cut off. Without treatment the bone can collapse and lead to severe arthritis of the hip.
Key symptoms
- Deep groin or buttock pain
- Pain with weight bearing that later also occurs at rest
- Limp and stiffness
- Often no symptoms early on
What you find on exam
- Pain and loss of internal rotation of the hip
- Antalgic gait
- Risk factors: steroids, alcohol, sickle cell disease, past hip trauma
- Check the other hip, since both sides are often affected
Tests
- Hip X-ray: normal early, later a crescent sign and flattening
- MRI: the most sensitive test for early disease
- Labs for causes as needed: blood count, lipids, sickle cell screen
Treatment basics
- Remove risk factors: limit steroids and alcohol
- Protected weight bearing with crutches and pain control
- Core decompression for early disease before collapse
- Total hip replacement once the femoral head collapses
Red flags
- Sudden worse pain suggesting collapse of the femoral head
- Hip pain in a patient on high-dose steroids
- Hip pain with fever, which may mean infection
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.