What would cause the outside of my left leg hurt daily with a burning pain behind my knee?

Hello Anon

Thank you for writing.

While you will need an examination and/or testing to know exactly what is wrong - you may have a torn meniscus. A meniscal tear is a tear in the meniscus, a shock-absorbing structure in the knee. There are two menisci (plural of meniscus) in each knee, one on the inside (medial), and one on the outside (lateral).

Torn meniscus may or may not cause symptoms. The ones that do not cause symptoms are usually small tears located in the back of the knee.

Symptoms may include:

"Popping" sound at the time of the injury
Pain and/or burning
Tightness
Swelling within the knee, often called "water on the knee"
Locking up, catching, or giving way of the knee
Tenderness in the joint

Diagnosis
The doctor will ask about your symptoms and how you injured your knee, and perform a physical exam. The doctor will perform physical tests to decide if there is a tear. Tests may include:

X-ray —a test that uses radiation to take a picture of structures inside the body. It will not show a meniscus tear, but may show some bone abnormality.
MRI scan —a test that uses magnetic radiation waves to make pictures of the inside of the knee. This is effective in diagnosing a meniscal tear.
Arthroscopy —a thin, lighted tube inserted through a small incision in the knee to look at the structures inside the knee. With the arthroscope, the tear will be seen and may be removed or repaired as deemed necessary.

Best,
Susan