A meniscus prosthetic device for a human knee joint can be inserted into the knee joint so that the articulating cartilage in the knee totally remains intact. The prosthesis device translates between the articulating cartilage during normal knee movement. Insertion of the prosthetic device is accomplished by applying force on the ends of the device, thereby elastically spreading them, and placing the device between the tibial articulating cartilage and one of the femoral condyles. The forces thus applied can then be released causing the device to conform to its original C-shape. Prominences on the ends of the device may superiorly extended into the space defined by the femoral condyles, thereby securing the device in place.