A knee orthosis is provided. In described embodiments, the knee orthosis is designed to follow a natural movement of a wearer's knee along an asymmetric helicoidal axis of rotation. In some embodiments, the knee orthosis has hinges with shells having displacing geometric centers which do not coincide. In some embodiments, the knee orthosis is made of femoral and tibial hinges manufactured as single integral pieces. In some embodiments, the orthosis is configured to realign the wearer's knee in a frontal plane. Corresponding methods for designing and manufacturing a custom knee orthosis are also provided.