The Rheo Knee XC from Ossur is a microprocessor-controlled knee designed to support patients from early rehabilitation to full recovery with intuitive and stable functionality. The Rheo Knee XC supports increased mobility including cycling, walk-to-run, and stair ascent. It features auto-adaptive, real-time stance and swing control with dependable swing initiation on all surfaces. The knee is designed to allow for automatic stumble recovery and features a manual extension lock. Weatherproof against exposure to fresh-water splashes. An Ossur Logic app for iOS devices provides easy practitioner setup and adjustment, printable user activity reports, functional training exercises, and selection of user preferences and step-count and battery charge monitoring.