Common Causes:

Knee pain usually results from overuse, poor form during physical activity, not warming up or cooling down, or inadequate stretching. Simple causes of knee pain often clear up on their own with self care. Being overweight can put you at greater risk for knee problems.

Knee pain can be caused by:

• Arthritis -- including rheumatoid, osteoarthritis, and gout
• Baker's cyst -- a fluid-filled swelling behind the knee that may accompany inflammation from other causes, like arthritis
• Bursitis -- inflammation from repeated pressure on the knee, such as kneeling for long periods of time, overuse, or injury
• Connective tissue disorders such as lupus
• Dislocation of the kneecap
• Iliotibial band syndrome -- a hip disorder related to injury of the thick band that runs from your hip to the outside of your knee
• Infection in the joint
• Knee injuries -- may cause bleeding into your knee, which worsens the pain
• Tendinitis -- a pain in the front of your knee that gets worse when going up and down stairs or inclines
• Torn cartilage (a meniscus tear) -- pain felt on the inside or outside of the knee joint
• Torn ligament (ACL tear) -- leads to pain and instability of the knee
• Strain or sprain -- minor injuries to the ligaments caused by sudden or unnatural twisting

Less common conditions that can lead to knee pain include the following:

• Bone tumors
• Osgood-Schlatter disease