Baker's Cyst

A baker's cyst is a benign swelling found behind the knee.

A baker's cyst is also known as a popliteal cyst which lies posterior to the medial femoral condyle. The cyst is connected to the knee through a valvular opening. Knee effusion from intra-articular pathology allows the fluid to go through the valve to the cyst in one direction.

• The patient usually has swelling behind the knee with pain, fullness, and tenderness.
• Baker's cyst is easier to see with knee fully extended.
• The diagnosis is confirmed by MRI, an ultrasound can also be helpful
• These tests are important especially if the cyst is found to be outside of its typical position.

Causes

There are two most common causes:-

• Knee arthritis
• Meniscal tear