Published on
Download the article PDF: Clinical Image Challenge December 2025
Differential Diagnosis
- Rickets
- Blount’s disease
- Pathologic asymmetric growth
- Skeletal dysplasia
Diagnosis
The x-ray demonstrates a varus‑aligned tibial shaft with a wedge‑shaped, fragmented epiphysis. There is a sharp downward slope of the medial tibial physis, and adjacent metaphyseal depression is seen, accompanied by a medial beak‑like spur. The correct diagnosis is Blount’s disease, a localized disturbance of growth in the medial aspect of the proximal tibial metaphysis and/or epiphysis that produces tibial varus, leg‑length discrepancy, and articular incongruity. Two clinical variants exist. Infantile Blount’s disease is typically diagnosed before age four, presents bilaterally in approximately 80% of cases, and worsens after the onset of walking. Adolescent Blount’s disease is diagnosed later in childhood and may be unilateral or bilateral. Predisposing factors include obesity, African‑American ethnicity, and early ambulation.
What to look for
- Assess for asymmetry: Asymmetric angular alignment of the lower extremities and/or focal angulation at the proximal tibia is often seen.
- Check degree of varus separation: With the child seated or supine, extend the knees and rotate the legs so that the patellae face anteriorly; a distance exceeding 6 cm between the femoral condyles in this position is considered abnormal.
- Observe the child’s gait: Observe while walking away from the examiner; assess foot and patellar progression angles and look for any lateral thrust of the tibia during ambulation.
- On x-ray, a sharp downward slope of the medial tibial physis is typical.
Pearls for Urgent Care Management
- Do not dismiss as physiologic bowing if child >2 years or if asymmetric
- Refer to pediatric orthopedics promptly as bracing or surgery may be required
- Advise avoidance of high-impact activities until a specialist has evaluated the patient
- Document growth, age, and weight – Blount’s is more common in obese children and early walkers
- Provide Anticipatory guidance emphasizing importance of follow-up imaging and ortho care to prevent progression
- Infantile Blount’s disease is often initially managed with bracing
- Adolescent Blount’s disease is typically treated with surgical intervention such as hemiepiphysiodesis or tibial osteotomy.