Pelvic Avulsion Fractures

Get CMEPelvic Avulsion FractureWe have discussed several overuse and sports related injuries (ex, Little League Shoulder, Osgood Schlatter’s, Patellofemoral Pain) and how children’s immature skeletal structure makes their injuries unique (ex, Ankle Injury, Lateral Condyle Fx, Supracondylar Fx). There is another unique pediatric apophyseal injury that deserves attention and results in a pelvic fracture. Let us take a minute to review Pelvic Avulsion Fractures.

 

Pelvic Avulsion Fracture: Basics

  • Relatively rare
  • Occurs primarily in adolescent atletes [Schuett, 2015; White, 2002]
    • Adolescents compete in strenuous activities.
    • Hormonal changes with puberty increase muscle strength.
    • Pelvic apophyseal centers don’t ossify until adolescence.
    • Weaker apophyseal cartilage may fail under stress and lead to avulsion fracture.
  • Commonly associated sports/activities:  [Schuett, 2015; Rossi, 2001White, 2002]
    • Sprinting (ex, track, soccer, baseball, football)
    • Jumping (ex, hurdles)
    • Kicking (ex, soccer)
    • Twisting (ex, swinging bat)
    • Gymnastics, especially floor exercise

 

Pelvic Avulsion Fracture: Anatomy Matters

  • Specific activities are associated with particular avulsion fractures based on anatomy.  [White, 2002]
  • Timing of the closure of the various ossification centers also influences when specific injuries occur. [Schuett, 2015]
  • Anterior Superior Iliac Spine (ASIS)
    • Origin of the sartorius muscle anteriorly  [White, 2002]
      • Sartorius muscle pulls ASIS anteriorly and inferiorly
      • Usually avulses a small fracture fragment.
      • Running activities are most commonly related to this injury pattern.
    • Origin of the tensor fascia lata laterally and posteriorly  [White, 2002]
      • The tensor fascia lata avulses a larger fragment in the lateral direction.
      • Twisting activities (ex, swinging bat) are most commonly related to this injury pattern.
  • Anterior Inferior Iliac Spine (AIIS)
    • Origin of the rectus femoris  [White, 2002]
    • Often seen when leg is kicked powerfully (ex, soccer, sprinting)
    • More likely to lead to chronic pain. [Schuett, 2015]
  • Ischial Tuberosity
    • Origin of the hamstring muscles  [White, 2002]
    • Avulsion of the ischial tuberosity occurs during hip extension (ex, gymnastic floor routine, sprinting, hurdling)  [Rossi, 2001]
    • This is when hamstrings are maximally stretched.

 

Pelvic Avulsion Fracture: Presentation

  • Popping or snapping sensation coinciding with physical exertion
  • A prodrome of low-grade pain affecting the site may have been present for several months prior to the injury; consistent with apophysitis [White, 2002]
  • Point tenderness over the region.
  • Swelling may be present.
  • Range of motion (both active and passive) may be completely normal.
  • Meralgia paresthetica can be associated. [Hsu, 2014; Hayaski, 2011]
    • Entrapment of the lateral femoral cutaneous nerve
    • Leads to pain, burning, and numbness over the anterior and lateral thigh.
    • Can occur because of compressive hematoma [Hsu, 2014] or entrapment by avulsed fragment. [Hayaski, 2011]
  • Radiographs
    • First choice for imaging. [Rossi, 2001]
    • Nearly all (99%) in one series were identified via plain radiographs. [Schuett, 2015]
    • Often able to demonstrate avulsion of the involved apophysis.
    • May need oblique, frog-leg, and/or axial projections
    • If the apophysis has not yet ossified, may be occult on radiographs.
  • Ultrasound
    • Can be used to demonstrate local hematoma formation. [Hsu, 2014]
  • CT and MRI are usually reserved for obscure cases or in the setting for surgical planning.

 

Pelvic Avulsion Fracture: Treatment

  • Therapy consists primarily of conservative management:
    • Brief period of rest followed by,
    • Protected weight bearing followed by,
    • Progressive stretching followed by,
    • Strengthening routine followed by,
    • Gradual return to sports
  • Surgical treatment (open reduction and fixation)
    • Conservative and surgical therapies lead to similar outcomes. [Kautzner, 2014]
    • Surgery is indicated in 3% of cases. [Schuett, 2015]
    • Surgery can lead to Full ROM sooner and tolerance of weight bearing and exercise can be achieved earlier. [Kautzner, 2014]
    • Surgery may be preferred for competitive athletes and those with greater displacement (>2 cm) of fracture fragments. [Kautzner, 2014]

 

Moral of the Morsel

  • Before you diagnosis a “hip sprain,” consider the age, mechanism, and those tricky growth plates! Kids are less likely to “sprain” and more likely to avulse a growth plate.
  • The adolescent athlete has the perfect storm of physical activity, strong muscles, and weak growth plates. Keep pelvic avulsion fracture on your differential for the adolescent with thigh, hip, and pelvic pain that occurs after sporting activity.

 

References

Schuett DJ1, Bomar JD, Pennock AT. Pelvic Apophyseal Avulsion Fractures: A Retrospective Review of 228 Cases. J Pediatr Orthop. 2015 Sep;35(6):617-23. PMID: 25321882. [PubMed] [Read by QxMD]

Kautzner J1, Trc T, Havlas V. Comparison of conservative against surgical treatment of anterior-superior iliac spine avulsion fractures in children and adolescents. Int Orthop. 2014 Jul;38(7):1495-8. PMID: 24695975. [PubMed] [Read by QxMD]

Hsu CY1, Wu CM, Lin SW, Cheng KL. Anterior superior iliac spine avulsion fracture presenting as meralgia paraesthetica in an adolescent sprinter. J Rehabil Med. 2014 Feb;46(2):188-90. PMID: 24158243. [PubMed] [Read by QxMD]

Naylor JA1, Goffar SL, Chugg J. Avulsion fracture of the anterior superior iliac spine. J Orthop Sports Phys Ther. 2013 Mar;43(3):195. PMID: 23455490. [PubMed] [Read by QxMD]

Hayashi S1, Nishiyama T, Fujishiro T, Kanzaki N, Kurosaka M. Avulsion-fracture of the anterior superior iliac spine with meralgia paresthetica: a case report. J Orthop Surg (Hong Kong). 2011 Dec;19(3):384-5. PMID: 22184178. [PubMed] [Read by QxMD]

White KK1, Williams SK, Mubarak SJ. Definition of two types of anterior superior iliac spine avulsion fractures. J Pediatr Orthop. 2002 Sep-Oct;22(5):578-82. PMID: 12198457. [PubMed] [Read by QxMD]

Rossi F1, Dragoni S. Acute avulsion fractures of the pelvis in adolescent competitive athletes: prevalence, location and sports distribution of 203 cases collected. Skeletal Radiol. 2001 Mar;30(3):127-31. PMID: 11357449. [PubMed] [Read by QxMD]

Veselko M1, Smrkolj V. Avulsion of the anterior-superior iliac spine in athletes: case reports. J Trauma. 1994 Mar;36(3):444-6. PMID: 8145340. [PubMed] [Read by QxMD]

Sean Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renown educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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