The Bump on the Back of Your Knee

Patients often ask, “Doc, what is the bump on the back of my knee?” This is commonly referred to as a Baker’s Cyst.  Located in the back of the knee lies a communication between the knee joint and the muscles behind the knee. Pressure from the Baker’s Cyst can often be painful, but what is most important is to find out why the cyst is being produced in the joint to begin with. There are multiple conditions within the knee that generate fluid that eventually presents as a Baker’s Cyst. Knee arthritis, meniscus tears, ligament tears, and gout can all cause large fluid collections in the knee. The excessive fluid (called synovial fluid) accumulation leaks between the semimembranosus muscle and the medial head of the gastrocnemius muscle, collecting in the back of the knee in an area called the popliteal space forming a Baker’s Cyst.

Baker’s Cysts are benign, and are not uncommon in several populations, including children, as well as patients with chronic knee pain.  If Baker’s Cysts are small and asymptomatic, patients may not even know they have one until it happens to be found during routine imaging for other knee problems.  Other times, Baker’s Cysts can become large enough that patients can see and feel them, and they can even prevent patients from fully flexing or bending their knee.

Patients should know that a Baker’s Cyst, while concerning to find, is often a common indication of acute or chronic injury deep inside the knee.  A Baker’s Cyst is worth mentioning to your orthopedist or healthcare provider, as it is often an indication of wear and tear on the inside of the knee joint that should be properly evaluated. If the cyst is asymptomatic no treatment is warranted. If symptomatic, treatment depends on the underlying cause. Treatment may include injections, NSAIDS, ice, and potentially surgery.

For more information, or if you feel you may be suffering from a Baker’s Cyst, schedule an appointment with Dr. Kyle and his team at Louisiana Orthopaedic Specialists at 337-235-8007.

Written by James B. Kyle MD & Cory E. Sehrt PA 04/01/2020