Question:easy
In a child with suspected developmental dysplasia of the hip (DDH), what is the investigation of choice?
In a child with suspected developmental dysplasia of the hip (DDH), what is the investigation of choice?
Show Hint
The infant hip is mostly cartilage and the bony nucleus has not ossified yet.
Updated On: Jun 24, 2026
- X-ray
- MRI
- USG
- CT scan
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: The key to this question is the age of the patient. DDH is screened and diagnosed in babies, and the chosen modality must work on an immature, mostly cartilaginous joint.
Step 2: Sound waves pass through and reflect off cartilage, so ultrasound maps the soft femoral head and the acetabular socket that bone-based imaging cannot yet show. It also runs in real time, letting the examiner stress the joint and watch for subluxation or dislocation as it happens.
Step 3: Contrast this with plain radiography, which depends on the bony ossific nucleus that has usually not appeared before about 4 to 6 months of age; until then a film looks essentially normal. CT delivers radiation and MRI is expensive and may demand sedation, so neither suits routine infant screening.
Step 4: A bedside, radiation-free, dynamic test that images cartilage is exactly what is needed, pointing to ultrasonography.
\[\boxed{\text{USG}}\]
Step 2: Sound waves pass through and reflect off cartilage, so ultrasound maps the soft femoral head and the acetabular socket that bone-based imaging cannot yet show. It also runs in real time, letting the examiner stress the joint and watch for subluxation or dislocation as it happens.
Step 3: Contrast this with plain radiography, which depends on the bony ossific nucleus that has usually not appeared before about 4 to 6 months of age; until then a film looks essentially normal. CT delivers radiation and MRI is expensive and may demand sedation, so neither suits routine infant screening.
Step 4: A bedside, radiation-free, dynamic test that images cartilage is exactly what is needed, pointing to ultrasonography.
\[\boxed{\text{USG}}\]
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