knee-iron

例句：

1. 1. He used a knee-iron to help him walk again after his knee surgery.
   他在膝盖手术后用膝盖护具帮助他再次走路。
2. 2. The coach gave the players a knee-iron to protect their knees during practice.
   教练给球员们一个膝盖护具，以保护他们在练习时膝盖。
3. 3. She was wearing a knee-iron as she walked across the stage.
   她穿着膝盖护具，在舞台上行走。