First Aid.

PRICE

PROTECT the knee from further trauma.
o This can be done with knee padding.
o A pad over the kneecap, for example, helps to control the symptoms of some knee injuries (an example is a form of bursitis sometimes called housemaid's knee) by preventing further repetitive injury to the prepatellar bursae.

REST the knee.
o Rest reduces the repetitive strain placed on the knee by activity.
o Rest both gives the knee time to heal and helps to prevent further injury.

ICE the knee.
o Icing the knee reduces swelling and can be used for both acute and chronic knee injuries.
o Most authorities recommend icing the knee 2-3 times a day for 20-30 minutes each time.
o Use an ice bag or a bag of frozen vegetables placed on the knee. ( Veges? HAHAHAHA. See, CThai, greens are good for you!! )

COMPRESS the knee with a knee brace or wrap.
o Compression helps accomplish 2 goals:
o First, compression is another way to reduce swelling.
o Second, in some knee injuries, compression can be used to keep the patella aligned and to keep joint mechanics intact.

ELEVATE the knee.
o Elevation also helps reduce swelling.
o Elevation works with gravity to help fluid that would otherwise accumulate in the knee flow back to the central circulation.
o Prop your leg up when you are sitting, or use a recliner, which naturally elevates the legs.

If first aid fails to relieve pain ..
• Over-the-counter pain control medications: Commonly used pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs) such as naproxen (Aleve or Naprosyn) and ibuprofen (Advil or Motrin) also play a role in the treatment of knee pain.
o These drugs directly control pain and, at higher doses, act as anti-inflammatory agents, helping to break the inflammatory cycle. Like all medications, however, these drugs have side effects.
o Acetaminophen (Tylenol) can also be used to control knee pain but does not have the anti-inflammatory properties of the NSAIDs. Still, this treatment is remarkably useful in many types of knee pain such as osteoarthritis.

Reference :
http://www.emedicinehealth.com/pdfguides/first_aid/knee-pain-overview-treatment-61794.pdf