The chest X-ray revealed that there have been some damage done to the ribs. When I fell, I happened to land on another person's knees.
ご質問ありがとうございます。
この文脈で「胸部X線で[肋骨](https://eikaiwa.dmm.com/uknow/questions/64497/)変形が判明。倒れ込んだ時相手の膝に当たった」と言いたいなら、英語で「The chest X-ray revealed that there have been some damage done to the ribs. When I fell, I happened to land on another person's knees.」と言います。
ご参考になれば幸いです。