In a 24-year-old female long-distance runner with acute right groin pain, antalgic gait, pain on internal rotation of the hip, tenderness of the anterior thigh, and normal radiographs, what is the most appropriate next step besides NSAIDs?

MRI of the Hip Without Contrast

You should order MRI of the hip and pelvis without contrast (option c) as the next step in management. 1

Clinical Reasoning

This 24-year-old female runner presents with classic features of a stress (fatigue) fracture of the hip:

• High-risk mechanism: Long-distance running with acute onset after competition 1
• High-risk location: Hip/femoral neck stress fractures carry significant complications if missed 1
• Characteristic clinical findings: Antalgic gait, inability to bear weight, pain with internal rotation, and anterior thigh tenderness 1
• Normal radiographs: Up to 10% of hip fractures are radiographically occult initially 1

Why MRI is the Definitive Answer

The American College of Radiology gives MRI hip without IV contrast a rating of 9/9 (usually appropriate) for suspected stress fracture of the hip with negative radiographs. 1 This is the highest possible appropriateness rating and represents the gold standard for this clinical scenario.

Key Advantages of MRI:

• Superior sensitivity and specificity for detecting occult hip fractures compared to all other modalities 1
• Detects stress fractures earlier than repeat radiography, bone scans, or CT 1
• Comprehensive soft tissue evaluation to identify alternative diagnoses (labral tears, muscle/tendon injuries, bursitis) 2, 3
• No radiation exposure - critical consideration in a young female patient 1
• Faster time to diagnosis and treatment compared to bone scintigraphy 1

Why Other Options Are Inappropriate

Physical Therapy (Option a):

• Contraindicated before excluding fracture in this high-risk scenario 1
• Weight-bearing activities could displace an occult femoral neck fracture, leading to catastrophic complications requiring urgent surgical intervention 1

CT Without Contrast (Option b):

• Rated only 5/9 (may be appropriate) by the American College of Radiology - reserved only when MRI cannot be performed 1
• Inferior to MRI for detecting early stress fractures and soft tissue pathology 1
• Unnecessary radiation exposure in a young patient when superior alternative exists 1

Repeat Radiography in 4 Weeks (Option d):

• Rated only 5/9 and explicitly discouraged by the American College of Radiology for hip stress fractures 1
• The ACR specifically states: "Because of the high risk of complications, it is not advisable to wait 10-14 days in most cases" 1
• Unacceptable delay that risks fracture displacement and avascular necrosis 1

Critical Pitfalls to Avoid

• Never delay advanced imaging in suspected hip stress fractures - the femoral neck is a high-risk location where complications can be devastating 1
• Do not allow weight-bearing or physical therapy until fracture is definitively excluded 1
• Recognize the Female Athlete Triad risk factors: Low BMI (18), amenorrhea concerns, and high-intensity training increase stress fracture risk 1
• Bone scans are obsolete for this indication - they may be falsely negative for 72 hours post-injury and have been superseded by MRI 1

Additional Management Considerations

While awaiting MRI:

• Strict non-weight-bearing status with crutches 1
• Continue NSAIDs for pain control 1
• Screen for Female Athlete Triad components (menstrual dysfunction, low energy availability, low bone density) given her low BMI and athletic profile 1