Huge intrameniscal cyst successfully treated by open debridement and combined arthroscopic and open repair: a case report

Background Meniscal cysts are not uncommon in clinical practice, with reported incidence rates varying from 1 to 22%. Most meniscal cysts are parameniscal cysts, which are created by extravasation of synovial fluid through the meniscal tear into the adjacent soft tissue. In contrast, intrameniscal cysts in which the fluid collects in the meniscus are very rare. We encountered a teenager with a huge intrameniscal cyst accompanied by a small vertical meniscal tear in the red-white zone of the upper surface of the medial meniscus. A literature search revealed no information regarding the appropriate treatment methods and results for this type of lesion. Case presentation A 14-year-old boy presented to our outpatient clinic because of right knee pain that had been present for the previous 2 months. The patient participated in Hapkido, but had no specific trauma history. Magnetic resonance imaging revealed a huge intrameniscal cyst located in the central parenchyma of the posteromedial corner of the medial meniscus. In addition, one sagittal slice on MRI revealed a vertical tear in the red-white zone of the upper surface of the medial meniscus. The presence of such a tear accompanied by a huge intrameniscal cyst is very unusual. The patient was treated via arthroscopic inside-out meniscal suture repair and open cystic debridement with additional meniscocapsular suturing. During 4 years of magnetic resonance imaging follow-up, the lesion has completely disappeared and the meniscus has successfully recovered its normal form. Conclusions Our treatment method may be considered as the first choice for young patients who require surgical treatment for large intrameniscal cysts with accompanying small vertical meniscal tears.