If you're feeling just a bit weak-kneed, you can take some steps on your own before heading into the doctor's office. First, if you are playing tackle sports like rugby and American football, don't. Sidelining yourself will significantly reduce the chances of a trauma injury to the legs' delicate hinges. Also, if you are overweight try to shed a few kilos. Most runners are aware that knees absorb much of the shock of pounding the pavement.
Fluid builds up, limiting motion and causing pain.
Often, knee injuries will heal on their own. First, immobilize the knee with braces, bandages or splints. Avoid activities that cause pain and stay off the knee as much as possible. To decrease pain and swelling, apply ice to the injured area. Compressing the joint with a tight bandage will also reduce swelling, and elevating the knee above the level of the heart will redirect the blood flow away from the joint.