。
She has an injury from being struck on the leg.
Literal
She [topic-は] leg [object-を] was-struck-and is-injured.
Note that けがいる reads as a typo or shortened form of けがしている / 怪我をしている ('is injured') — けが alone followed by いる isn't grammatical in standard Japanese. Setting that aside, 足を打たれて is an indirect/adversity passive: 'her leg was struck' from the speaker-empathy perspective of the person affected. The ~を passive (rather than ~が) is one of the marked uses of the Japanese passive — emphasizing the suffering experiencer.