Ischiofemoral impingement

Dr Tim Luijkx et al.

Ischiofemoral impingement refers to the impingement of soft tissues between the ischial tuberosity and lesser trochanter of the femur, primarily the quadratus femoris muscle. Narrowing of the distance between these two osseous landmarks (ischiofemoral space) predisposes for and correlates with ischiofemoral impingement 1,2.

Radiographic features

Plain radiograph

A recent study suggested ischiofemoral impingement is likely in patients with chronic pelvic pain if the ischofemoral space is <2 cm or <1.9 cm on supine and standing pelvic x-rays, respectively. It warrants further investigation by pelvic MRI 5.

  • STIR/T2 FS: high signal in impinged soft tissues, primarily the quadratus femoris muscle
  • ischiofemoral space cut-off for IFI: ≤15 mm (sensitivity 77%, specificity 81%) 1

History and etymology

Ischiofemoral impingement was first described as a cause for hip pain by K A Johnson in 1977 4

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Article information

rID: 39031
Section: Syndromes
Synonyms or Alternate Spellings:
  • IFI
  • Quadratus femoris impingement
  • Ischiofemoral impingement syndrome

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Cases and figures

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    Case 1: bilateral IFI
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    Case 2: left-sided IFI
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    Case 3
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    Case 4
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