Does mild bone marrow edema in the hip indicate a fracture in a 13-year-old female?

Bone Marrow Edema Does NOT Mean Fracture in This Case

The mild bone marrow edema at the anterior superior iliac spines in this 13-year-old female represents a stress response (stress reaction), not a fracture. The radiologist's interpretation explicitly states "without associated avulsion" and "favored to reflect stress response," which distinguishes this from an actual fracture 1.

Understanding Bone Marrow Edema vs. Fracture

Key Distinction

• Bone marrow edema alone indicates increased interstitial fluid within the bone marrow and represents a spectrum of injury that ranges from stress reaction to actual fracture 2
• A fracture requires a visible cortical or trabecular fracture line, not just edema 1
• The ACR guidelines emphasize that MRI can show edema patterns that are "nonspecific and even confusing when only edema and not the fracture line is shown" 1

What the MRI Shows

The findings in this case indicate:

• Stress response/reaction: Early stage of repetitive stress injury where bone remodeling cannot keep pace with microtrauma, causing edema but no discrete fracture line 1
• Location at sartorius origin: The anterior superior iliac spine is a common site for stress-related changes in young athletes due to repetitive pull from the sartorius muscle 3
• No avulsion: The report specifically excludes an avulsion fracture, which would represent actual bone separation 1

Clinical Significance in a 13-Year-Old

This is a Stress Reaction, Not a Fracture

• In pediatric athletes, bone marrow edema at muscle attachment sites typically represents chronic physeal or apophyseal stress injury rather than acute fracture 4
• The absence of periosteal elevation, soft tissue edema, and joint effusion strongly argues against acute fracture 4
• Stress reactions show focal physeal thickening and can demonstrate discontinuity of the zone of provisional calcification without representing a complete fracture 4

Risk Stratification

• This represents a low-risk stress injury that is typically self-limiting with activity modification 1
• The anterior superior iliac spine is not considered a high-risk location for fracture completion (unlike femoral neck, anterior tibial diaphysis, or navicular) 1
• Without a visible fracture line on MRI, this does not require the same management as an actual fracture 1

Management Implications

Conservative Treatment is Appropriate

• Activity modification and relative rest are the mainstays of treatment for stress reactions 1
• This does not require immobilization or the restrictions needed for actual fractures 2
• The condition is typically reversible with appropriate load management 2

Monitoring for Progression

• If symptoms persist or worsen despite conservative management, repeat imaging may be warranted to assess for progression to actual fracture 1
• Clinical correlation is essential: increasing pain with activity or failure to improve with rest should prompt reassessment 1

Common Pitfall to Avoid

Do not equate bone marrow edema with fracture. The ACR guidelines specifically warn against "overreliance on nonspecific low-signal T1 and high-signal T2 MRI patterns" leading to misdiagnosis 1. The edema in stress reactions is typically more pronounced and linear on T2-weighted sequences, and the absence of a discrete fracture line on MRI is the critical distinguishing feature 1.

The radiologist's interpretation as "stress response" rather than fracture should guide clinical management toward activity modification rather than fracture treatment protocols 1.