Posterior Cruciate Ligament Ganglion: Case Report

Intra-articular ganglion of the knee is uncommon and it shows non-specific symptoms. In this report, we present for a treatment of the ganglion arising from the PCL and the mechanism of pain. The case is a 33-year-old male with pain in his left knee. On presentation, he had no history of locking or giving way of the knee, but had pain on standing. At the first medical examination, the range of motion of his knee was full, with no loss of extension, and there was no effusion or swelling, but the terminal knee flexion was painful. McMurray’s test was negative, and the collateral and cruciate ligaments were clinically stable. On MRI, ganglion cysts droved from PCL appear as well-defined cystic multiloculated masses. The patient underwent arthroscopy through the standard anteromedial and anterolateral portals. Consequently, it was diagnosed as a ganglion cyst. The pain disappeared completely after the surgery and neither PCL ganglion nor symptoms recurred up to 9 months post-surgery. The intra-articular ganglion of the knee often is asymptomatic and discovered incidentally. But the reports of ganglion cysts of the knee have been increasing with the increasing availability and use of MRI. We considered that the mechanism of the pain due to ganglion in the cruciate ligament was stimulation of the synovial nerve terminal. One key point for consideration in this study is that arthroscopy should be performed through posterior portal to observe the whole of the PCL and ganglion cysts because it was difficult to observe both the PCL and ganglion cysts with anterior portal. While arthroscopy did not confirm continuity of the ACL and meniscus, it was considered that the ganglion cysts developed in the PCL because of the continuity with the PCL.