What is behind knee lump?

A swollen area or lump that can be felt behind your knee can be caused by several different conditions. The lump may create an unsightly appearance, limit knee flexibility, or generate discomfort. A Baker’s cyst is a collection of synovial fluid (the fluid that is present within joint spaces) that bulges out through the back of the knee joint and can be felt as a lump behind the knee. Knee injuries, arthritis, damage to the cartilage of the knee, and other problems can all result in the development of a Baker’s cyst.
The majority of individuals with Baker’s cyst experience no symptoms. The cyst may be found during radiologic imaging for other joint complaints.

A lump behind the knee may be painful or may not produce any other symptoms. In some cases, you may experience tenderness, warmth, difficulties with movement of your knee joint, or bleeding or bruising.

Other possible causes of a lump behind the knee include abscesses (infections); tumors of the skin, soft tissue, or bones; bleeding; or deformity of the joint accompanying a fracture or other injury to your knee.

A lump behind your knee may be associated with injury and may be accompanied by more serious injuries to the joint. Seek immediate medical care (call 911) for serious symptoms, such as paralysis or inability to move a body part, loss of sensation, absent pulses in the feet, uncontrolled or heavy bleeding, or uncontrollable pain.

If your knee lump is persistent or causes you concern, seek prompt medical care.


SYMPTOMS

What other symptoms might occur with behind knee lump?

Behind knee lump may accompany other symptoms, which vary depending on the underlying disease, disorder or condition.

Localized symptoms that may occur along with behind knee lump

Behind knee lump may accompany other localized symptoms including:

CAUSES

What causes behind knee lump?

A Baker’s cyst is a common cause of a lump behind the knee. This condition develops when joint fluid leaks out from the joint cavity into the tissues behind your knee. Other causes include infections, bleeding, trauma, and, rarely, tumors.

Infectious causes of behind knee lump

Behind knee lump may be caused by infectious processes including:

Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Aug 23, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

This Article is Filed Under: Bones, Joints and Muscles


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