The following pelvic x-ray is from a 12 year old who has experienced left knee pain for the past few weeks. What can you notice in the x-ray?

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The pelvic x-ray shows a left slipped capital femoral epiphysis (SCFE) and Klein’s line is abnormal on the left.

A normal Klein’s line is when a line drawn along the superior border of the femoral neck intersects with the femoral head. In SCFE, this line does not intersect with the femoral head.

SCFE:

• Capital femoral epiphysis stays in the acetabulum and the neck displaces anteriorly and externally rotates.
• Most common hip disorder affecting adolescents.
• Male to female ratio is 3:2
• Bilateral in 17-50% of cases (important to look at the unaffected hip when the pelvic x-ray is obtained in the ED)
• Increased BMI is the single greatest risk factor
• Non-obese children under 10 with SCFE need work up for endocrine issues (hypothyroidism/CRF)
• Groin and thigh pain are the common presenting symptoms. 1 in 4 can present as knee pain.
• Imaging should include AP and Frog leg lateral of both hips. Lateral view identifies the slip when it is subtle. Plain x-ray features take time to manifest. If the condition is strongly suspected, MRI is the modality of choice when the x-ray appears normal.
• All patients will need urgent referral to the specialist.

Thanks to Dr. Sani Haxdy for the image.

Reference: www.orthobullets.com

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