Locking and Damping Mechanism for a Prosthetic Knee Joint

A high performance, low-cost passive prosthetic knee includes one or more modules to enable able-bodied gait by transfemoral amputees to improve metabolic efficiency and reduce stigma from conspicuous abnormal gaits. A stance stability module includes a latch with a virtual lock axis that automatically locks and unlocks. An early stance flexion module enables able-bodied gait during stance. Hydraulic fluid dampers ensure reliable swing phase control. A swing extension energy storage module stores and returns energy as the knee locks and unlocks, respectively. These modules may be used together, in any combination, or individually.