TOACS FCPS Station · X‑ray Long Bones: Rickets

📷 X‑ray Long Bones (Wrist AP view)

X-ray long bones showing classic findings of rickets – metaphyseal fraying and cupping

Figure 1 · AP radiograph of wrist · Rickets – Metaphyseal Changes

🔍 Key radiographic features:

✓ Widened growth plate (physis) – increased distance between epiphysis and metaphysis
✓ Metaphyseal fraying – loss of the sharp, smooth border of the metaphysis
✓ Cupping – concave deformity of the metaphysis
✓ Coarse trabeculation – thickened, irregular bone trabeculae
✓ Generalized osteopenia (decreased bone density)

📋 Clinical scenario (examiner prompt)

A 19‑month‑old exclusively breastfed infant presents with delayed walking and bowed legs. On examination, there is widening of the wrists, a rachitic rosary at the costochondral junctions, and craniotabes. An X‑ray of the long bones (wrist) is shown.

Exclusively breastfed Widened growth plate Metaphyseal fraying Rachitic rosary

🧑‍⚕️ Examiner tasks · TOACS

1. Identify the diagnosis from the X‑ray and clinical context.

2. Describe the radiographic findings (widened growth plate, metaphyseal fraying, cupping).

3. Explain the pathophysiology (vitamin D deficiency → impaired mineralization).

4. Discuss diagnostic workup and treatment (labs, vitamin D supplementation).

⚠️ Key concept: The widened growth plate with metaphyseal fraying and cupping are the classic radiographic hallmarks of rickets. Vitamin D deficiency leads to inadequate mineralization of osteoid at the growth plate, resulting in these characteristic changes.

🎯 Expected answers (for examiners)

• Diagnosis: Nutritional rickets (vitamin D deficiency)
• X‑ray findings: Widened growth plate, metaphyseal fraying, cupping, coarse trabeculation, osteopenia
• Pathophysiology: Vitamin D deficiency → decreased intestinal calcium/phosphate absorption → impaired bone mineralization
• Workup: Serum calcium, phosphorus, ALP, PTH, 25-OH vitamin D
• Treatment: High-dose vitamin D (stoss 300,000-600,000 IU or daily 2000 IU x3 months) + calcium

⚡ Quick FCPS‑style MCQ

The radiographic finding of metaphyseal fraying and cupping in a 19‑month‑old with bowed legs is most consistent with:

A. Rickets B. Scurvy C. Osteogenesis imperfecta D. Lead poisoning

📌 Topic summary ·

Definition
Vitamin D deficiency → impaired bone mineralization

X‑ray findings
Widened growth plate, metaphyseal fraying, cupping

Lab findings
Low Ca, low PO4, high ALP, high PTH, low 25-OH D

Treatment
Vitamin D (stoss 300,000-600,000 IU) + calcium

Prevention
Breastfed infants: 400 IU/day vitamin D

Risk factors
Exclusive breastfeeding, dark skin, high latitude

Radiographic Feature	Description
Widened growth plate	Increased distance between epiphysis and metaphysis
Metaphyseal fraying	Loss of sharp metaphyseal border
Cupping	Concave deformity of metaphysis
Coarse trabeculation	Thickened irregular bone trabeculae
Osteopenia	Decreased bone density

🩻 TOACS FCPS Station · X‑ray Long Bones: Rickets

📷 X‑ray Long Bones (Wrist AP view)

🧑‍⚕️ Examiner tasks · TOACS

📌 Topic summary ·