Efficient functioning of the joints in the human body is extremely important for mobility, well-being and overall quality of life. Operations to replace the hip joint with an artificial implant are well established, although they are invasive and involve the removal of tissue, resulting in sometimes long and painful recoveries for the patients. A device is proposed to reduce the compressive and shear strains on regions of the joint surfaces affected by osteoarthritis, whilst providing a surface with a low coefficient of friction against which the joint can articulate. It will be implemented through minimally invasive, or potentially arthroscopic, procedures. The implant will be formed from flexible materials and consist of two components: a sac and a filler. The device works by having no relative movement between the implant and the bone; instead, opposing surfaces of the implant move relative to one another facilitated by the inner filler material. As the joint articulates the device will move into the space where it is required. The mechanism is comparable to that of a caterpillar track on a tank, but working in three-dimensions. The design process consisted of materials testing, friction testing, manufacturing techniques, implementation, and public patient involvement. The motivation behind the design was the need for an improved innovative solution for people who suffer from osteoarthritis. The project outcome evidenced that the device concept is feasible.