Major vascular injury after knee arthroscopy is rare. The patient was a 22-year-old woman and her chief complaint was pain of the right knee seven days after arthroscopic posterior cruciate ligament reconstruction. Contrast-enhanced computed tomography demonstrated a 50×38×40 mm pseudoaneurysm and arteriovenous fistula of the right popliteal artery. Emergent surgery was performed. Using the medial approach, direct repair of the artery and vein was performed. Her postoperative course was uneventful.