She fell and got hurt.

Literal

She [topic-は] fell [and-て] injury [object-を] did.

けがをする ('to get injured') is the standard expression for sustaining an injury — けが (怪我) is the noun, and をする makes it a verbal phrase. This is more general than ひざを痛めた ('hurt one's knee') or 腕を折った ('broke one's arm') — it reports the injury without specifying the body part.