A 4-month-child diagnosed with DDH, cast used after closed reduction is:
**Core Concept**
Developmental dysplasia of the hip (DDH) is a condition where the hip joint does not form properly, leading to instability and potential dislocation. Closed reduction is a procedure to gently move the femoral head into the acetabulum, and casting is a common method to maintain the reduced position.
**Why the Correct Answer is Right**
The Spica cast is a type of cast used for DDH in infants, providing immobilization and support to the hip joint. This cast is applied with the child in a flexed and abducted position, allowing the femoral head to settle into the acetabulum. The Spica cast is typically used for 2-3 months to allow for proper healing and development of the hip joint.
**Why Each Wrong Option is Incorrect**
**Option A:** Pavlik harness is used for DDH in infants, but it's not a type of cast. It's a fabric or plastic harness that holds the infant's legs in a position that allows the hip joint to develop properly.
**Option B:** Plaster of Paris (POP) cast is not suitable for DDH in infants due to its rigidity, which can cause skin irritation and pressure sores.
**Option C:** Thomas splint is a type of cast used for fractures, not DDH in infants.
**Clinical Pearl / High-Yield Fact**
The Pavlik harness is a valuable tool in the management of DDH in infants, as it can be used to treat the condition without the need for surgery.
**Correct Answer: C. Thomas splint is a type of cast used for fractures, not DDH in infants.**