Popliteal Cyst

Introduction:

A cyst is a collection of fluid in a small sac. A Popliteal Cyst is a soft, often painless bump seen in the Popliteal area (back side of the knee). It is also referred to as a bakers cyst. The weakening of the joint capsule in the damaged area can cause the small sac of fluid to form. It can increase in size over a period of time.

Causes:

  • A tear in the Meniscal Cartilage of the Knee
  • Knee Arthritis (in older adults)
  • Rheumatoid Arthritis
  • Other Knee problems

Baker's Cyst

Clinical Features:

Swelling behind the knee, discomfort or minimal pain

Special Tests:

  • Since it communicated with the knee joint, it can be pushed back into the knee during flexion
  • Transillumination, or shining a light through the cyst, can show that the growth is fluid filled

Investigations:

MRI of the knee will confirm the diagnosis but it is rarely indicated.

Treatment:

Usually no treatment is needed except observation.
If the cyst is painful, the goal of treatment is to correct the problem, 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.

Complications:

Rupture & increase in size.