A meniscal cyst is an out pouching of joint (synovial) fluid along the peripheral margin of the meniscus. It is frequently associated with a meniscal tear through which the fluid flows from the joint to the cyst. It is more common on the lateral aspect of the knee.
The patient notices a firm bump on the side of the knee. There may also be symptoms of the meniscal injury e.g. locking or giving way. The cyst can be painless or painful especially with standing on the affected leg.
The doctor may ask for an MRI to confirm the diagnosis and to detect the presence of any meniscal tear.
Meniscal cysts typically do not heal naturally. Treating a meniscal cyst consists of diagnostic arthroscopy to determine the presence of a meniscal tear. If there is a meniscal tear, partial meniscectomy followed by arthroscopic cyst decompression is the treatment of choice. If a tear is not confirmed at the time of arthroscopy, then open-cyst decompression with peripheral meniscal repair is done, leaving the body of the meniscus intact.