Physiotherapy clinic

Behind Knee Lump


Healthgrades Editorial Staff

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.

Looking for a Doctor?

Find a 5-Star Orthopedic Specialist Near You

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.


8 Rheumatoid Arthritis Myths

Debunking common RA myths will help you manage your condition and communicate your experience to your loved ones.

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.

Medical Reviewers: William C. Lloyd III, MD, FACS Last Review Date: Oct 3, 2016

© 2017 Healthgrades Operating Company, Inc. All rights reserved. May not be reproduced or reprinted without permission from Healthgrades Operating Company, Inc. Use of this information is governed by the Healthgrades User Agreement.

View Sources

Medical References

  1. Baker’s cyst. PubMed Health, a service of the NLM from the NIH.
  2. Knee problems.
  3. Hayashi D, Roemer FW, Dhina Z, et al. Longitudinal assessment of cyst-like lesions of the knee and their relation to radiographic osteoarthritis and MRI-detected effusion and synovitis in patients with knee pain. Arthritis Res Ther 2010; 12:R172

You Might Also Like


11 Ways to Relieve Pain with Psoriatic Arthritis

Medicines, steroid injections, physical therapy, massage or gentle exercise may help.
Myth #7: If I stay on the couch, I'll be fine.

10 Don'ts for Rheumatoid Arthritis

When facing the symptoms of RA, avoid these common pitfalls that can set your treatment back.

Share via Email


Hand Cramps


Neck Spasm
Neck Spasm

Up Next

Neck Spasm