Fast-tracking prosthetic feet

In Cambodia alone there are an estimated 30,000 to 50,000 amputees.

In an attempt to make some positive difference to this disturbing worldwide problem, teams of final-year students supervised by Associate Professor Peter Lee Vee Sin from the University of Melbourne’s Department of Mechanical Engineering have been conducting research on various kinds of low-cost artificial limbs. Supported by Dreamlarge Student Engagement Grants in both 2009 and 2010, the students’ year-long research projects have culminated in field trips to Cambodia to visit rehabilitation clinics as well as prosthetics and orthotics centres to gain insight on manufacture, usage and design problems.

“Going to Cambodia was incredibly instructive on a number of levels,” says Oliver Hare, one of a group of four students with an abiding interest in biomedical engineering who travelled there for 10 days last September.

“I don’t think any of us really appreciated the magnitude of the problem or understood the burden amputees face when trying to cope with hopelessly inadequate prostheses. It seems that everywhere we looked we saw people struggling with well-worn, damaged artificial limbs that, at best, only last for a couple of months anyway.”

A key aspect of Associate Professor Lee’s work is its organic nature. Each year, the research of the graduating team informs the research of the following year’s group.

“For example,” says Associate Professor Lee, “the 2009 team designed a prototype prosthetic knee joint for testing by the International Committee for the Red Cross (ICRC), and an apparatus to mechanically test the knee for structural integrity and functionality.”

This in turn led the team to design a successful low-cost prosthetic knee that overcame some of the more significant problems associated with the prevailing design at that time. But on return they also presented a much larger and more immediate problem – the structural shortcomings of the existing prosthetic foot design.

“What we discovered is that the locally-made foot is structurally very strong,” says Mr Hare, “and that the main setbacks with its design and production actually relate to the weight and the ability of the polypropylene keel to adhere to the surrounding rubber.”

The Department of Mechanical Engineering is also conducting a patient trial in Hanoi, in collaboration with the Vietnamese Training Centre for Orthopaedic Technologies (VIETCOT), to produce good-fitting artificial limbs that are relatively inexpensive and require minimal skill to manufacture. This project is funded by the Melbourne-based CASS Foundation and the Rotary Club Richmond.

“Using objective parameters such as stump anatomy, body weight and an evenly distributed pressure over an amputee’s stump, we have shown that an acceptable prosthetic fit can be produced using a pressure-casting technique we have developed,” says Associate Professor Lee. “Due to the lack of skilled practitioners in developing countries, this method will have an immediate impact in addressing a prevailing worldwide problem.”

See: www.mech.unimelb.edu.au/people/staff/peter_lee.html