Knee1.com- Baker's Cysts

EDUCATION CENTER: Clinical Overview

Clinical Overview Symptoms Diagnosis and Treatment Complications

Baker's Cysts

Clinical Overview

Three bones meet within the knee joint: the femur (thighbone), the tibia (shinbone) and the patella (kneecap). Between the three bones lies a bursa, a fluid-filled sac that lubricates the joint. As a result of age and wear, the bursa may create extra fluid. The fluid may leak out of the wall of the bursa, forming a fluid-filled sac known as a Baker's or Popliteal cyst. The condition can be painful and often accompanies osteoarthritis, gout or a meniscal injury.

Causes
A popliteal cyst is caused by swelling of the bursa, or fluid filled sac, around one of the muscles that forms the hamstrings in the back of the thigh (the semimembranosus muscle). Its formation may be triggered by overuse, arthritis, injury, gout, or meniscal injury.

Risk Factors
Degenerative conditions of the knee, such as arthritis or meniscal injury, can put a person at risk for developing popliteal cysts. Different types of popliteal cysts affect children and the middle aged, but both are at risk of contracting them.

Last updated: Sep-01-09