What could cause my "creaking knees"?

Osteoarthritis . Osteoarthritis of the knees is the loss of the articular cartilage of the knee which is the cartilage that caps the ends of the bones. This is often described as creeking knees.
Cartilage damage. Sound coming from the knee could be due to tendon, cartilage, or bone abnormalities. Have it evaluated by a specialist and find out why it is making that sound.