• Clinical science

Osteonecrosis of the femoral head (Avascular necrosis of the femoral head)

Abstract

Osteonecrosis of the femoral head is a consequence of insufficient vascular supply to the femoral head. Most cases are either idiopathic or associated with alcohol, corticosteroid therapy, or trauma. The condition presents with groin pain, which may radiate to the knee or ipsilateral buttock, and limited range of motion at the hip. Diagnosis is based on x-ray, followed by MRI. No curative treatments have been identified. Initial nonsurgical treatment focuses on preventing collapse of the femoral head, although surgical intervention may be required if the disease progresses. However, there is no consensus regarding the best treatment options.

For avascular necrosis of the femoral head in children, see Legg-Calvé-Perthes disease.

Epidemiology

  • Peak incidence: 20–40 years

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Several traumatic and atraumatic factors are known contribute to the etiology of osteonecrosis, all of which contribute to changes in blood supply.

ASEPTIC: alcohol, sickle cell disease/SLE, exogenous steroid, pancreatitis, trauma, infection, caisson disease (decompression sickness)

References:[1][2][3][4]

Clinical features

  • Slowly progressive groin pain, which may radiate to the knee or ipsilateral buttock
  • Limited active and passive range of motion at the hip
  • Bilateral in 50% of cases

Consider osteonecrosis in patients presenting with groin pain and a history of corticosteroid use or alcohol abuse.

References:[1][2][3]

Diagnostics

  • X-ray (best initial test)
    • Cystic and sclerotic changes in the femoral head
    • Subchondral collapse
    • Flattening of the femoral head
  • MRI: (best confirmatory test) : used to the visualize necrotic-viable bone interface
  • Staging
    • Evidence the bone is pre/post-collapse
    • Size of the necrotic component
    • Amount of femoral head depression
    • Acetabular involvement
    • ARCO staging
      • Stage 0 (initial stage) → normal imaging studies; histological evidence of change
      • Stage I (reversible early stage) → positive MRI, normal x-ray
      • Stage II (irreversible early stage) → X-ray and MRI positive, preserved contour
      • Stage III (transitional stage) → X-ray: subchondral fracture
      • Stage IV (late stage) → calcification, resorption cysts and formation of new cartilage in the x-ray image

Early diagnosis via MRI or scintigraphy is possible!

References:[1][2][3]

Treatment

  • No known curative treatment
  • Reduce risk factors; (smoking; cessation, alcohol; abstinence, reduce corticosteroid use if possible)
  • Conservative treatment: indicated in early stages of disease to the reduce risk of femoral head collapse
  • Surgery: indicated in later stages of disease when bone structure is compromised
    • Prophylactic
      • Core decompression: decompressing femoral head to restore normal vascular flow
      • Bone graft to fill necrotic area
      • Osteotomy to redistribute weight load
    • Reconstructive

References:[1][2][3][4]

Complications

References:[2][3]

We list the most important complications. The selection is not exhaustive.

last updated 08/23/2018
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