Meniscal tear of the knee causing cystic adventitial disease of popliteal artery: support for the synovial theory.

Cystic adventitial disease is a rare cause of calf claudication and is characterized by the development of a mucinous, cystic mass within the outer layer (adventitia) of an artery. The popliteal artery is most commonly affected. Several theories and hypotheses exist regarding the aetiology of this disorder with no clear unifying cause accepted in the literature to date. We describe a case of a 32-year-old female with a one-year history of medial right knee pain and intermittent claudication who was diagnosed with a medial meniscal tear and a large parameniscal cyst communicating with the popliteal artery adventitia. She underwent arthroscopic meniscectomy and cyst decompression and achieved an excellent functional outcome with resolution of the claudication.