Open Repair of Intrameniscal Cysts With Fibrin Clot Augmentation

Cysts involving the meniscus are commonly identified on magnetic resonance imaging (MRI) of the knee. Most meniscal cysts are defined as parameniscal cysts created by synovial fluid extravasation through a tear in the meniscus into the adjacent soft tissues. Intrameniscal cysts are less common and do not extend to the articular surface. These cysts represent a management dilemma for the treating clinician, where established guidelines do not exist. Surgical management of intrameniscal cysts is based on initial diagnostic arthroscopy, confirming the absence of an intra-articular tear, which would otherwise be treated in the standard manner based on tear characteristics. An open approach to the affected side is made with an "L-shaped" capsulotomy performed to expose the peripheral meniscus. The meniscus is then incised transversely, and the degenerate tissue debrided with a curette and rasp. An autologous fibrin clot is prepared and placed in the defect and held with absorbable sutures. Patients with recalcitrant symptoms with a positive clinical examination and an MRI demonstrating intermediate signal without a tear should be considered for diagnostic arthroscopy and open repair. Failure to recognize this subset of meniscal cysts can lead to falsely negative arthroscopic assessments, resulting in untreated pain and mechanical symptoms.