Kager fat pad

Kager fat pad (also known as the pre-calcaneal fat pad or pre-Achilles fat pad) refers to the fat within the Kager triangle, which normally appears lucent (fat density) on radiographs and has relatively well-defined margins. Pathologies affecting nearby structures result in loss of the normal margins and increased density in the triangle.  

Related pathology

Normal appearance of Kager fat pad can be distorted by:

  • oedema
  • haemorrhage
  • infection (e.g. soft tissue, osteomyelitis)
  • inflammation (e.g. retrocalcaneal bursitis, peritendinitis)
  • thickened tendons (xanthomatosis, rheumatoid arthritis, gout, ankylosis spondylitis, reactive arthritis)
  • adjacent neoplasm (soft tissue, osseous)

In the setting of trauma, oedema in Kager's fat pad should lead to a careful search for bony or soft tissue injury (i.e. Achilles tendon injury), perhaps requiring additional views and/or cross-sectional imaging depending on the clinical suspicion.

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Article information

rID: 32094
Section: Anatomy
Synonyms or Alternate Spellings:
  • Pre Achilles fat pad
  • Kager's fat pad
  • Pre-calcaneal fat pad
  • Kager fat pads

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