Baker’s cyst
St. Luke's Hospital
Main Number: 314-434-1500 Emergency Dept: 314-205-6990 Patient Billing: 888-924-9200
Find a Physician Payment Options Locations & Directions
Follow us on: facebook twitter Mobile Email Page Email Page Print Page Print Page Increase Font Size Decrease Font Size Font Size
America's 50 Best Hospitals
Meet the Doctor
Spirit of Women
Community Health Needs Assessment
Home > Health Information

Multimedia Encyclopedia

Baker’s cyst

Definition

Baker's cyst is a buildup of joint fluid (synovial fluid) that forms a cyst behind the knee.

Alternative Names

Popliteal cyst; Bulge-knee

Causes

A Baker's cyst is caused by swelling in the knee. The swelling is due to an increase in synovial fluid - the fluid that lubricates the knee joint. When pressure builds up, fluid bulges into the back of the knee.

Baker's cyst commonly occurs with:

  • A tear in the meniscal cartilage of the knee
  • Knee arthritis (in older adults)
  • Rheumatoid arthritis
  • Other knee problems

Symptoms

A large cyst may cause some discomfort or stiffness, but there are often no symptoms. There may be a painless or painful swelling behind the knee.

The cyst may feel like a water-filled balloon. Sometimes, the cyst may break open (rupture), causing pain, swelling, and bruising on the back of the knee and calf.

It is important to know whether pain or swelling is caused by a Baker's cyst or a blood clot. A blood clot (deep venous thrombosis) can also cause pain, swelling, and bruising on the back of the knee and calf. A blood clot may be dangerous and requires immediate medical attention.

Exams and Tests

During a physical exam, the health care provider will look for a soft lump in the back of the knee.

  • If the cyst is small, comparing the affected knee to the normal knee can be helpful.
  • There may be a decrease in range of motion caused by pain or by the size of the cyst.
  • In some cases there will be catching, locking, pain, or other signs and symptoms of a meniscal tear.

Shining a light through the cyst  (transillumination) can show that the growth is fluid filled.

If the lump grows quickly, or you have night pain, severe pain, or fever, you will need more tests to make sure you do not have other types of tumors.

X-rays will not show the cyst or a meniscal tear, but they will show other problems that may be present, including arthritis.

MRIs can help the health care provider see the cyst and look for any meniscal injury.

Treatment

Often no treatment is needed. The health care provider can watch the cyst over time.

If the cyst is painful, the goal of treatment is to correct the problem that is causing the cyst, such as arthritis or a meniscus tear.

Sometimes, a cyst can be drained (aspirated) or, in rare cases, removed with surgery if it becomes very large or causes symptoms.

  • The cyst has a high chance of returning if the cause is not addressed.
  • The surgery may also damage nearby blood vessels and nerves.

Outlook (Prognosis)

A Baker's cyst will not cause any long-term harm, but it can be annoying and painful. The symptoms of Baker's cysts usually come and go.

Long-term disability is rare. Most people improve with time or arthroscopic surgery.

When to Contact a Medical Professional

Call for an appointment with your health care provider if you have swelling behind the knee that becomes large or painful. Pain could be a sign of infection.

References

Foley BA, Christopher TA. Injection therapy of bursitis and tendinitis. In: Roberts JR, Hedges JR, eds. Clinical Proceedings in Emergency Medicine. 5th ed. Philadelphia, Pa: Saunders Elsevier;2009:chap 52.

Huddleston JI, Goodman SB. Hip and knee pain. In: Firestein GS, Budd RC, Harris ED Jr., et al., eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 42.

Biundo JJ. Bursitis, tendinitis, and other periarticular disorders and sports medicine. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 271.


Review Date: 6/29/2012
Reviewed By: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; and C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
adam.com
 


Back  |  Top
About Us
Contact Us
History
Mission
Locations & Directions
Quality Reports
Annual Reports
Honors & Awards
Community Health Needs
Assessment

Newsroom
Services
Brain & Spine
Cancer
Heart
Maternity
Orthopedics
Pulmonary
Sleep Medicine
Urgent Care
Women's Services
All Services
Patients & Visitors
Locations & Directions
Find a Physician
Tour St. Luke's
Patient & Visitor Information
Contact Us
Payment Options
Financial Assistance
Send a Card
Mammogram Appointments
Health Tools
My Personal Health
mystlukes
Spirit of Women
Health Information & Tools
Clinical Trials
Health Risk Assessments
Employer Programs -
Passport to Wellness

Classes & Events
Classes & Events
Spirit of Women
Donate & Volunteer
Giving Opportunities
Volunteer
Physicians & Employees
For Physicians
Remote Access
Medical Residency Information
Pharmacy Residency Information
Physician CPOE Training
Careers
Careers
St. Luke's Hospital - 232 South Woods Mill Road - Chesterfield, MO 63017 Main Number: 314-434-1500 Emergency Dept: 314-205-6990 Patient Billing: 888-924-9200
Copyright © St. Luke's Hospital Website Terms and Conditions  |  Privacy Policy  |  Patient Notice of Privacy Policies PDF Sitemap St. Luke's Mobile