What can i do for a sprained knee?

RICE: This stands for rest, ice, compression and elevation. You need to make sure none of the ligaments or meniscus are torn. If there is a significant amount of fluid or swelling in the knee there is a greater likelihood of this. Get evaluated by your doctor, he or she can refer you for pt or orthopedics if needed it may be worse than you think.

Many options: Depending on the condition some treatment options may include rest, ice, compression and elevation, bracing, injection, pain medication, anti-inflammatory medication, physical therapy, and surgery. Have it evaluated and get the appropriate treatment.