Project Circleg – low cost prosthetic leg system

What it does

In less developed countries there is a lack of satisfactory and affordable prosthetic systems. Project Circleg closes this gap by using recycled plastic waste and simple production methods. The Circleg can therfore be produced locally and cost-effectively.

Your inspiration

As industrial designers we are driven by the notion of using plastic waste as a resource for meaningful products. 72% of the worldwide yearly plastic consumption for packaging ends up in nature or in landfills. Such landfills are often found in less developed countries (LDCs), due to the lack of official recycling systems. At the same time, the demand for low cost prosthetic legs is high in LDCs mainly due to traffic accidents, poor medical care or armed conflict. Combining those findings, we aim at using plastic waste as a resource for prosthetics in order to simultaneously satisfy a social demand and tackle an urgent environmental issue.

How it works

Circleg is a prosthetic leg for above and below knee amputees. It is designed to be fully modular and consists of two adapters, a knee joint, a pilone and a foot with an ankle joint. The adapters enable the individual adjustment to the user. The ankle joint allows a squatting position and thus the use of a squat toilet. This is a very important aspect in many LDCs. The polycentric knee joint is equipped with a protection cap and a mechanism which swings the leg forward while walking in order to prevent dangerous trip hazards. The Circleg prosthesis is made of recycled polypropylene (PP) post-consumer plastic waste. It is reinforced with glass fibres to create a composite material that meets the high-performance requirements of a leg prosthesis. All parts are manufactured by injection molding or extrusion, differentiating between standard parts and components individually adapted to the user. Outstanding repairability is guaranteed thanks to the modular system.

Design process

We started this project with in-depth research into the fields of plastic waste and prosthetics. Both topics are highly complex and we interviewed various experts in order to gain the knowledge we needed to develop this system. During a research trip to Kenya in March 2018 we gained insights into existing plastic waste recycling industries as well as low-cost prostheses projects. In addition, we were able to discuss ideas with amputees and got to know their everyday lives and difficulties. This user-centered approach enabled us to integrate the needs and requirements of those affected into our design process. Subsequently, we designed and developed a prosthesis system tailored to the Kenyan context. In order to fully understand the mechanics and functions of a leg prosthesis we built many functional prototypes. A dedicated test-rig allowed us to test them ourselves . The challenge was to design a modular prosthetic system that would provide the highest functionality with the lowest financial means. In addition, the leg prosthesis should function in a material cycle where individual parts can be repaired or replaced. Such a leg prosthesis system ensures that even the poorest can afford an urgently needed leg prosthesis.

How it is different

In comparison with existing low cost prosthetic systems Project Circleg provides higher functionality for a still affordable price. This not only brings more comfort to the user, but adds some vital functions for daily activities like using a toilet. The modular system allows the replacement and repairing of broken parts and obviates the disposal of a whole prosthetic leg, when only a part is damaged. Additionally, the different parts can be produced in various colors offering one’s individually customized prosthetic leg. Thanks to the use of the polypropylene composite material, the Circleg prosthesis only weighs 1.5 kg being a lot lighter than existing low-cost prosthesis and therefore significantly improving comfort.

Future plans

Project Circleg is evolving from a degree project to a start-up business. We are continuing to further develop the prototype and the system: Refining and testing the prototype will be the next step. As a starting point we focus on the implementation in Kenya. The project is perfectly scalable and could have great impact everywhere, where low cost prosthetic legs are needed. We are excited to push this project to the implementation and wish to make a difference by using design.

Awards

Student Award of the Design Department at Zurich University of the Arts, Student Award of the Institute for Design Research at Zurich University of the Arts, Award for Excellent Business Pitch, UZH Innovators Camp 2018