A 15 y.o. female presents to your emergency department with sudden onset hip pain after winding up to kick a soccer ball during her game today. You see a well-developed female in obvious discomfort, with tenderness to palpation over her lateral hip and pain with passive ROM at the hip. You obtain this x-ray. What is your diagnosis?
Answer: Avulsion fracture of the anterior superior iliac spine.
Injury:
An avulsion fracture of the anterior superior iliac spine is an uncommon injury seen almost exclusively in adolescent athletes.
They mostly result from a sudden, forceful, and/or unbalanced contraction of the attached musculotendinous unit (sartorius muscle or tensor fascia lata) during the starting phase of running, jumping, kicking, etc.
The most implicated sports include soccer, running, and ice hockey.
History/Exam:
The patient may report sudden shooting pain referred to the involved tuberosity.
Physical exam may include localized edema and tenderness to palpation and pain on passive ROM at the hip.
Anatomy:
The iliac crest is the weakest component of the pelvic ring during adolescence.
The avulsed fragment is usually displaced distally and laterally.
Treatment:
Conservative therapy includes 2-3 weeks of limited activity and walking with partial weight bearing restrictions and crutches. May also include bed rest with the affected lower extremity positioned with the hip and knee in flexion to ensure minimal tension of the muscles attaching to the ASIS. This is considered for minimally displaced fractures in younger children.
Surgical management generally consists of ORIF with a lag screw, and is generally recommended for patients with fracture fragments > 3cm or severely displaced fragments that cause compression of the lateral cutaneous nerve resulting in meralgia parasthetica.
Rossi F, Dragoni S. Acute avulsion fractures of the pelvis in adolescent competitive athletes: prevalence, location and sports distribution of 203 cases collected. Skeletal Radiol. 2001;30(3):127-31.
Kautzner J, Trc T, Havlas V. Comparison of conservative against surgical treatment of anterior-superior iliac spine avulsion fractures in children and adolescents. Int Orthop. 2014;38(7):1495-8.
