OBJECTIVE The purpose of the study is to assess the orientation and distance of the popliteal artery (PA) from both the anteromedial and anterolateral portals. METHODS The records of 97 patients (100 knees) who underwent knee arthroscopy were reviewed. The shortest distance from the posterior tibial cortex to the PA on the lines from both the medial and lateral borders of the patellar tendon to the PA was evaluated by magnetic resonance imaging at full knee extension. The figure-of-four position was compared between patients with intact and deficient anterior cruciate ligaments (ACLs). The shortest distances from the posterior cruciate ligament (PCL) to the lines running from the medial and lateral borders of the patellar tendon to the PA were also measured. RESULTS The shortest distances from the posterior tibial cortex to the PA were significantly longer in the figure-of-four position than at full knee extension and during extension in the ACL-deficient than intact group. Distances did not significantly differ in the figure-of-four position. The PA was hidden from the anteromedial portal by the PCL, but remained vulnerable from the anterolateral portal. CONCLUSIONS All-inside meniscus suturing of the posterior horn of the lateral meniscus inserted through the anteromedial portal is safer when the knee is in the figure-of-four position than fully extended. Meniscus repairs should be completed before ACL reconstruction due to vascular positions and the ease of approach. METHODS Prospective correlation study, Level IV.