Final answer:
The Denis-Browne bar is used to treat clubfoot or talipes equinovarus, a congenital deformity where a newborn's feet are rotated inward. It is a part of the Ponseti method, which includes manipulation, casting, and the bar's use to maintain correction.
Step-by-step explanation:
The musculoskeletal abnormality that requires the use of a Denis-Browne bar for at least 23 hours a day is clubfoot, also known as talipes equinovarus. The Denis-Browne bar is a device used during the corrective treatment for clubfoot, consisting of a metal or plastic bar with shoes attached at both ends. It is designed to hold the child's feet in the correct position, maintaining the correction achieved through earlier treatments like casting or surgery.
Clubfoot is a congenital deformity wherein a newborn's foot or feet are rotated inward at the ankle. The Denis-Browne bar is important in the Ponseti method, which is a conservative treatment approach involving manipulation and casting followed by the use of the bar to prevent relapse of the condition.