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Case of the Week 252

What's the most likely diagnosis?

  • 78 year-old female with back pain

  1. Metastases to sacrum
  2. Sacral insufficiency fracture
  3. Osteoid osteoma
  4. Bladder cancer
  5. Ankylosing spondylitis



2. Sacral insufficiency fracture



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Sacral insufficiency fractures

General considerations

  • Normal sacrum almost never sustains an isolated fracture
  • They usually occur associated with other pelvic fracture and imply a force frequently sufficient to injure pelvic organs
  • Insufficiency and fatigue fractures are subgroups of stress fractures
  • Insufficiency fractures are fractures in abnormal bone (e.g. osteoporosis) which undergoes normal stress
  • Fatigue fractures are fractures in normal bone which undergoes abnormal stress (e.g. March fractures)
  • In the sacrum, such fractures occur in
    • Postmenopausal women with osteoporosis (more common after age 60)
    • Long-term corticosteroid use
    • Such as those with rheumatoid arthritis or collagen-vascular disease
    • Those who have undergone radiation therapy to the pelvis


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