The position of 90° of knee flexion is safe to establish posterior and transseptal arthroscopic portals. The position of 120° of knee flexion is practically safe to establish posteromedial and transseptal portals, but it is unsafe to create a posterolateral portal because the risk of damaging the common peroneal nerve is high. The position of 30° of knee flexion is not recommended to establish posterior arthroscopic portals.

Therapeutic study, Case series with no comparison group, Level IV.

IV (retrospective series).

Level IV retrospective study.

Level III, low-power prospective study.