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Case of the Week 286

What's the most likely diagnosis?

  • 20 year-old athlete 10 days post injury with pain

  1. Diastasis of the symphysis pubis
  2. Fracture of the iliac crest
  3. Diastasis of the sacroiliac joint
  4. Avulsion of the lesser trochanter
  5. Avulsion of the ischial tuberosity

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4. Avulsion of the lesser trochanter



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Avulsion of the Lesser Trochanter

General Considerations

  • Avulsion fractures result when the fracture fragment is pulled from its parent bone by forceful contraction of a tendon or ligament
  • Avulsion fractures are most common in younger individuals engaging in athletic endeavors
  • In the pelvis, the newly formed secondary centers of ossification, the apophyses, are the most likely portions of the bone to avulse
  • Since the apophyses tend to form at the time of puberty, most of these pelvic avulsions occur at the time of puberty
  • In general, they are uncommon injuries, seen almost exclusively in adolescent athletes with a 2:1 male to female preponderance
  • They occur most often in track events like hurdling and sprinting, or games like soccer or tennis
  • Most common to avulse is the ischial tuberosity followed by anterior inferior iliac spine (AIIS) and the anterior superior iliac spine (ASIS) about equally
  • Prompt diagnosis will prevent development of chronic pain

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