回答

・have water on one's knee
・fluid collects under one's knee

「膝蓋有積水」可以用英文 have water on one's knee 或 fluid collects under one's knee 來表達。

It looks like you have water on your knees. Do you have any pain?
（看起來你的膝蓋有積水。你感到疼痛嗎？）

If you fluid collects under your knee, you will not be able to participate in the game.
（如果膝蓋後面有積水，你將無法參加比賽。）

有幫助｜0