case 26 Sacral insufficiency fractures
A 67-year-old female presents to your clinic with pelvic and groin pain for 5 days after a low-impact fall from sitting height. On examination she has full asymptomatic hip ROM and remains ambulatory with the above symptoms. Radiographs films are negative for fracture, and you decide to send her for nuclear imaging, of which a representative image is shown in Figure 6–31.
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Figure 6–31
What is the name of the radiographic finding pictured below and what pathology does this represent?
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H-sign, iliac crescent fracture
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H-sign, sacral insufficiency fracture
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Lambda-sign, sacroiliitis
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Lambda-sign, iliac crescent fracture
Discussion
The correct answer is (B). The image below displays an H-sign as seen with sacral insufficiency fractures. Lambda is a fracture morphology seen in complex sacral fractures. Iliac crescent fractures are a component of the LC-II type pelvic ring injury. Sacroiliac joint pathology would likely not have the central uptake within the sacrum on this imaging modality.
What is the estimated incidence of this specific form of pathology in women over 55 years of age, and what is the most common cause?
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1%, postmenopausal osteoporosis
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5%, low-energy trauma
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10%, postmenopausal osteoporosis
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25%, low-energy trauma
Discussion
The correct answer is (A). Commonly these postmenopausal females will present with no history of acute trauma. The mainstay of treatment is conservative with bedrest/early mobility.
Objectives: Did you learn...?
Diagnosis of sacral insufficiency fracture?
Incidence and most common cause of sacral insufficiency fracture?