Osteonecrosis of the Femoral Head

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Osteonecrosis of the Femoral Head

• Matthew Orton
• Radiology Presentation
• 7/20/2007

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HPI

• A 20 yo male with SLE reports to ER complaining
  of chronic L hip pain and new L knee pain that
  has not resolved since fall 1 week ago.
• PCP diagnosed SLE in 2004.
• Meds Lisinoprol, Prednisone, Zantac, HCTZ,
  Imuran, Volteran,

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• Sclerosis and density changes
• Crecent Sign subcondral radiolucancy

• Loss of smooth spherical or collapse of femoral
  head.
• Joint space narrowing , degenerative changes.

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MRI of Femoral Head Osteonecrosis

• Coronal T1 MRI of both hips shows diffuse low
  signal throughout the left femoral head, neck,
  and proximal shaft.

• Axial T2 MRI of both hips shows diffuse high
  signal in the left femoral head consistent with
  the avascular necrosis.

Images from brighamrad.harvard.edu
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Osteonecrosis of Femoral Head

• Osteonecrosis aseptic necrosis, avascular
  necrosis, ischemic necrosis and osteochondritis
  dessicans.
• Mechanism? compromise of bone vasculature leading
  to death of bone and marrow cells and ultimately
  mechanical failure. Process is often progressive
  and results in joint destruction in 3-5 years if
  untreated.
• Exact pathogenesis still under debated. Some
  theories include intravascular necrosis,
  increased intraosseous pressure, mechanical
  stresses, or metabolic factors.
• Prevalence is 10,000-20,000 cases diagnosed in
  US/year. MF 81. 5 of patients with SLE will
  develop osteonecrosis.
• Staging
• Stage 0 All diagnostic studies normal,
  diagnosis by histology
• Stage 1 Plain radiographs and computed
  tomography normal, magnetic resonance imaging
  positive and biopsy positive.
• Stage 2 Radiographs positive but no collapse.
• Stage 3 Early flattening of dome, crescent
  sign, computed tomography or tomograms may be
  needed.
• Stage 4 Flattening of femoral head with joint
  space narrowing, possible other signs of early
  osteoarthritis

Nontraumatic
Corticosteroid
Sickle cell
Systemic lupus erythematosus
Gauchers Disease
Chronic renal failure or hemodialysis
Radiation
Excessive ETOH
Traumatic
Femoral Neck Fracture
Femoral Dislocation
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Treatment of Osteonecrosis of Femoral Head

• Conservative management ( rest and pain control)
  if lt15 femoral head involved.
• Bisphosphonates can slow progression
• Core decompression may slow progression.
• Osteotomy move areas of necrosis away from major
  load bearing and try to redistribute on healthy
  bone.
• Joint replacements (higher rate of complications
  and revisions)

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References

1. Donohue, JP.UptoDate Osteonecrosis (avascular
   necorsis of bone). 2007.
2. Jones LC, Hungerford DS. Osteonecrosis etiology,
   diagnosis, and treatment. Curr Opin Rheum 2004
   16 443-449.
3. Galindo M, Mateo I, Pablos JI. Multiple avasular
   necrossis of bone and polyarticular septic
   arthritis in patients with systemic lupus
   erythematosus. Rheumatol Int 2005 25 72-76.