Final answer:
Plantar creases are assessed in newborns to help indicate Down syndrome, rather than clubfoot, which is a separate condition treated with corrective casting.
Step-by-step explanation:
Plantar creases need to be evaluated within the first hours of birth because they may indicate Down syndrome. Plantar creases, or the lines on the soles of the feet, are more pronounced and numerous in babies with Down syndrome, and assessing these can be part of an early detection strategy. In contrast, clubfoot, also known as talipes, is a congenital condition where the foot is twisted inwards and may require treatment to avoid future issues with walking, though it is not directly related to plantar creases. Clubfoot treatment often starts with gentle corrective casting techniques and can be very effective, especially when initiated within the first 2 weeks after birth.