When should the external approach be resorted to in the arthroscopic treatment of perimeniscal cyst?

Introduction: Meniscal cysts very often cause meniscal tears and especially when it is peripheral, some of the healthy parts of meniscus might be needlessly sacrificed. In particular conditions, extraarticular approaches might save some menisci. In the present study, we evaluated the conditions which required using the extraarticular approach in addition to the arthroscopic procedure, to maximally preserve the meniscus.
Methods: Eight patients with perimeniscal cysts were evaluated retrospectively. One cyst was localized within the medial meniscus and seven in the lateral meniscus. The mean age was 36.13 (range; 19-63) years, mean follow-up time, 27.3 (range; 12-47) months. Patients were evaluated by using a Visual Analogue Score (VAS) to measure pain relief and "Lysholm score" to measure functional improvement. In all patients except one, in which the cystic cavity was connected with the joint at the periphery of the meniscus, the cyst was drained from the intraarticular opening. When the cyst was too large (three cases) and in one case where a large amount of meniscus was preserved for reasons mentioned above, additional extraarticular drainage was carried out.
Results: The mean preoperative and postoperative VAS were 6 (range; 2-8) and 1.55 (range; 0-3) (p = 0.00058) and Lysholm scores were 64.75 (range; 48-86) and 93.11 (range; 80-100) (p = 0.0014), respectively.
Discussion: In cysts, which have very limited or no connection with the joint on the most peripheral region of the meniscus and/or are larger than the meniscus height, extraarticular drainage of the cyst might produce unnecessary meniscal loss and function. In the extraarticular drainage, scrapping the walls of the cyst, while inspecting with an arthroscope, reduces recurrence of the cyst.