ARTHROSCOPIC EXCISION OF A GANGLION FORM WITHIN THE POSTERIOR SEPTUM OF THE KNEE

Abstract

Introduction We describe an arthroscopic technique of excising a lesion from within the posterior septum of the knee. To our knowledge this has not been described in the literature.

Case History A 35-year old male taxi-driver presented with pain in the back of his right knee. Examination did not reveal any abnormality except pain on flexing the knee beyond 90-degrees. MRI showed a multiloculated ganglion in the posterior compartment of the knee. The ganglion was located within the posterior septum and successfully excised arthroscopically. 6-months postoperatively the patient is assyptomatic.

Anatomy of the posterior septum The posterior septum is located between the posterior cruciate ligament (PCL) and the posterior capsule dividing the posterior cavity of the knee into seperate posteromedial and posterolateral compartments. It is triangular in shape, formed by the reflections of the synovium from the PCL.

The Technique The posterior septum of the knee was approached through the intercondylar notch by the anterior portals. Slow and careful dissection was carried out in the V-shaped space between the anterior and the posterior cruciate ligaments. The synovium of the septum was resected and the space within the septum entered. The ganglion was successfully removed. There was no complication. The relatively central placement of the anterior portals is important to gain access to the posterior septum via the notch.

Discussion and conclusion Intra-articular ganglion cysts are uncommon. Reported prevalence ranges from 0.2% to 1.3%. Ganglion cysts arising from the anterior and the posterior cruciate ligaments have been well described. The ganglion cyst within the posterior septum has not been reported.

The anatomy of the posterior septum makes it inaccessible to routine arthroscopic examination. It has close proximity to the vascular structures. We approached the posterior septum from the anterior portals through the intercondylar notch. The ganglion was successfully excised.