。
Both her legs are paralyzed.
Literal
She [topic-は] both-legs [subject-が] are-paralyzed.
両足が麻痺している — 麻痺する (まひする, 'to become paralyzed') is a medical suru-verb. The resulting-state ている indicates a persistent condition. The topic-subject split (彼女は...両足が) is a classic double-subject construction: 'as for her, both legs are paralyzed.'