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Dr. Allan Mishra | Knee Pain Diagnosis



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Definition  An invasion of the knee joint by a bacteria or other organism

Model and X-ray of a Normal Knee
Details Knee infections most commonly are caused by bacteria. Other types of organisms such as a fungus can also cause joint infections but these occur much less frequently.
Causes There are many ways a knee can become infected. Direct trauma to the knee with a puncture wound into the joint can lead to a deep infection. Fractures when the bone breaks through the skin (Compound Fractures) are especially vulnerable to infection. A sexually transmitted disease (gonorrhea) can also lead to a knee infection by traveling there via the bloodstream. Knee surgery is another risk factor for deep infection. Finally, patients with a compromised immune system or who have an artificial knee are at higher risk for joint infection. Special precautions are sometimes needed for these patients during dental procedures to help prevent infection.
Diagnosis The diagnosis of a knee infection is made by a history of severe pain in the knee associated with fever, chills and an inability to move the knee. Usually, it is also not possible to walk on the leg of the affected knee. On physical exam, the knee is swollen, warm and sometimes red. X-rays reveal the knee swelling and may show joint destruction if there is infection deep into the bone.

An aspiration (sticking a needle into the joint) is the definitive way of diagnosing a knee infection. Any fluid obtained from the knee is sent to the lab for analysis immediately. Rarely, a MRI or other test is needed to aid in making the diagnosis.

Knee Aspiration
Treatment A true knee infection is a surgical emergency. The knee needs to be drained as soon as possible. This can initially be done with an aspiration but typically a severe infection requires surgery. This can take the form of an arthroscopy (use of small incisions and instruments to evaluate and treat joint problems) or may require opening of the knee with larger incisions.

Knee Arthroscopy

Patients with artificial knees or patients in immuno-suppressed states may require antibiotic treatment prior to dental procedures.