Final answer:
Applying ice to the knee and elevating the leg is the most appropriate action to take initially because it helps stop bleeding, decrease swelling, and alleviate pain.
Step-by-step explanation:
Applying ice to the knee and elevating the leg is the most appropriate action to take initially because it will help to stop the bleeding, decrease the swelling, and help alleviate the pain. Ice helps to constrict blood vessels, which can reduce bleeding and swelling. Elevating the leg helps to reduce swelling by allowing fluid to drain away from the affected area. Additionally, it can help alleviate pain by reducing pressure on the injured knee.