Definition

Any pain in the knee.

Alternative Names

Pain - knee(s)

Considerations
Knee pain is a fairly common complaint. The majority of knee pain complaints stem from use trauma, are fairly acute, and resolve without treatment or with mild pain medications.
Significant trauma with torn or ruptured ligaments results in both pain and an unstable knee joint. The knee is also the site of other types of injuries such as dislocation of the knee-cap (patella), patellar bursitis, joint effusions.
Pain may be referred to the knee from the hip as in Legg-Calve-Perthes disease, where the actual disease is in the hip but the first symptom may be knee pain. Other conditions that can lead to knee pain are infection in the joint (septic joint), arthritis, blood in the knee joint (hemarthrosis), bone tumors, Baker cyst, and Osgood-Schlatter disease.
Moderate exercise (such as walking ) does NOT cause knee problems. If the knee is not injured, exercise is generally good for the knee. Side stresses, which the knee is not engineered to withstand very well, cause most knee injuries.
Uneven cartilage wear can cause the leg to bow in or bow out. Being overweight can also contribute to knee problems.

Common Causes

ligament or cartilage damage due to trauma or injury
ACL injury
MCL injury
LCL injury
osteoarthritis
rheumatoid arthritis
acute gouty arthritis
adult Still's disease
Baker cyst
bursitis
chondromalacia patellae
chronic gouty arthritis
gonococcemia (disseminated gonococcal infection)
Osgood-Schlatter disease
pseudogout
psoriatic arthritis
Reiter's syndrome
systemic lupus erythematosus
systemic sclerosis (scleroderma)

Home Care
Rest, apply ice, and elevate the knee to bring any swelling down. Gentle compression with an elastic bandage may reduce swelling and provide support. Avoid activities that aggravate the pain.

Call your health care provider if

the knee cannot tolerate weight bearing.
there is an associated fever.
there is severe pain when not bearing weight.
the pain is persistent after 3 days of home treatment.
there is pain or swelling in the calf below the sore knee.

What to expect at your health care provider's office
The medical history will be obtained and a physical examination performed.
Medical history questions documenting knee pain in detail may include:

time pattern
When did the knee first begin to hurt?
How long has this episode of knee pain lasted?
Is the pain continuous or off-and-on?
location
Are both knees affected?
Is the pain in the entire knee?
Is the pain in the kneecap?
Is the pain on the outer side of the knee?
Is the pain on the inner surface of the knee?
Is the pain below the knee?
quality
Is the pain severe?
Does it feel bruised?
Can you stand? Can you walk?
aggravating and triggering factors
Have you had an injury or accident involving the knee?
Have you overused the leg?
relieving factors
What home treatment have you tried?
How well did it work?
other
What other symptoms are also present?
Is there knee swelling?
Is there a fever?
Is there swelling in the calf of the leg?
The knee and other joints will be examined and taken through their range of motion (the area of normal joint movement).

Diagnostic tests that may be performed include:

fluid drawn from the knee and analyzed
X-ray of the knee
Intervention:
Some knee problems can be treated with medication or surgery.

After seeing your health care provider:

You may want to add a diagnosis related to knee pain to your personal medical record.