Fluid-filled sacs that develop behind the knee are called popliteal cysts. They can be hard to get rid of and come back repeatedly after treatment. They often have thick, twisted roots that go deep. Two doctors from South Korea report on the use of arthroscopy to remove large popliteal cysts.
The study included 14 patients with cysts that caused loss of knee motion, pain, and pressure on the nerves. These patients were compared to a control group of eight patients with the same condition who had open surgery instead of arthroscopy.
In arthroscopic cyst removal, the doctor inserts a long, slender tool into the fluid-filled sac. A tiny TV camera on the end gives the doctor a good view inside. Fluid is removed from the cyst. Using a small, motorized shaver, the cyst is then shaved away. Doctors are careful to keep the shaver pointed away from nerves and blood vessels.
During the operation any flaps, thick bands, or other fibrous membranes are removed. Surgeons check the knee joint for other damage. They often find frayed cartilage, meniscal tears, and arthritic changes. Arthroscopy allows them to treat these problems at the same time the cyst is taken out.
All patients having arthroscopic removal of the cyst had a good result. The cyst didn't come back in anyone. Pain, swelling, and tissue tension were all gone by the end of three days. Patients were followed for at least one year and some for up to three years. The authors report this is a great improvement from past results, in which the cyst would return in at least half of all patients.
The authors of this study conclude that large, recurrent cysts behind the knee can be successfully treated using the arthroscope. The wall of the cyst and a valve must be removed for this to work. The authors also advise surgeons to correct other problems in the knee joint at the same time. This operation works well for patients who've had the needed to have fluid removal three or more times.
SangHun Ko, MD, PhD, and JinHwan Ahn, MD. Popliteal Cystoscopic Excisional Debridement and Removal of Capsular Fold of Valvular Mechanism of Large Recurrent Popliteal Cyst. In Arthroscopy. January 2004. Vol. 20. No. 1. Pp. 37-44.'