Endoscopic Resection of Medial Extra-articular Cysts of the Knee.

Although most of the parameniscal cysts are very small and asymptomatic, some of them can present with a painful mass or snapping knee. Because parameniscal cysts are almost always associated with horizontal meniscal tears, arthroscopic partial meniscectomy of the involved part of meniscus and intra-articular cyst drainage has become the most accepted procedure. However, arthroscopic cyst decompression through partial meniscectomy to the meniscocapsular junction to expose the communication between the cyst and the knee joint may sacrifice some of the healthy parts of the meniscus especially when meniscal tear is peripheral. Moreover, internal drainage may not be an adequate treatment for a cyst larger than 5 cm in size or a multiloculated cyst. The excision of the cyst is a more appropriate treatment option in these situations. The purpose of this Technical Note is to describe the details of endoscopic resection of medial extra-articular cysts of the knee. This technique is indicated in symptomatic medial extra-articular cysts of the knee with peripheral or no tear of the medial meniscus, especially if the cysts are large and multiloculated.