gms | German Medical Science

Introduction: Intra-articular ganglia are rare findings in the knee joint and mostly incidental findings in magnetic resonance imaging (MRI) and arthroscopy. Even more rarely, those lesions are found arising from the cruciate ligaments. Many theories have been suggested for the origin of ganglion cysts, including a herniation of synovial fluid and cells through a defect in ligament fibers similar to those of wrist joint origin, connective tissue degeneration after trauma and proliferation of pluripotential mesenchymal stem cells. However, in some cases, they represent congenital anomalies.

Methods: We present 4 cases of intra-articular ganglion cysts of the knee in 3 patients, associated with the anterior cruciate ligament. Medical history, clinical examination and MRI evaluation were performed. In addition, arthroscopic excision and histological examination of the lesions were performed. Type of study: Case series. Level of Evidence: IV

Results: In one patient ganglion cysts appeared in both knees with a time difference of one year. Only one patient had suffered a trauma prior to the onset of the symptoms. All the other patients’ histories were negative for any knee injury. Regardless of their anatomical location, these ganglion cysts are commonly associated with mild localized pain, which is usually intermittent and aggravated after stressing activities. They are also frequently associated with recurrent effusions or locking in the extremes of flexion or extension mimicking other forms of internal derangement of the knee. MRI is the most sensitive and specific method for diagnosis. Arthroscopic excision of the lesions was performed and relief of the symptoms was achieved to all the cases. Histological examination suggested a lesion consisted mainly of loose connective tissue with extensive mucoid degeneration, leading to cyst formation, and interspersed thicker bundles of collagen, confirming the diagnosis of ganglion cysts of the cruciate ligaments.

Conclusion: in the case of chronic knee discomfort with non-specific clinical signs and symptoms and without a clear aetiology, an intra-articular ganglion cyst should be considered as causing pathology. The pre-operative MRI is the most sensitive and specific method for depicting this cystic mass including its size and location, for evaluating the joint for associated lesions, and for avoiding misdiagnosis. However, the relatively slow progression of symptoms may considerably delay the patient’s decision to seek medical attention. When this lesion is discovered early it can be treated successfully with an arthroscopic debridement. Late discovery makes the total resection of the ganglion technically demanding or not possible at all and may result in the weakening of the cruciate ligament due to extensive debridement.