PTO stands for Patella Tracking Orthosis and HP for High Performance. The orthosis is unique in its kind and is mainly used for unstable or luxating kneecaps but also for anterior knee pain when support and medialization of the kneecap are needed. The lateral pressure against the patella is progressive and begins early at about 30° flexion and increases up to full extension. The force is individually regulated with the front bands at the peloton. The PTO HP has aluminum joints that are customizable for individual fit, comfort, and increased lateral stability. It also has rigid front and back bands that keep the joints parallel. The orthosis has an "Open back", i.e. opening at the back of the knee for increased comfort. The orthosis is made of airmesh.