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
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.