A student team at Stanford University, as part of a course called Biomedical Device Design and Evaluation, created an artificial knee that costs less than $20 to manufacture. Already implanted in dozens of people in India, the honorably named JaipurKnee may become as successful an invention as its earlier cousin, the JaipurFoot, after which it was named.
Old models of low-cost knee joints used a single-axis joint, which rotated like a door hinge. They were unstable and unsafe for India’s varied terrain; the joint tended to buckle under weight, which could be physically as well as psychologically painful for a freshly fitted amputee.
To build a better model, Sadler and his team studied the mechanics of high-end titanium knee joints in the United States, which cost from $10,000 to $100,000, he said. The team also surveyed the materials used to build cheap prosthetics for developing countries. Armed with this information, the team designed a versatile knee joint made from an oil-filled nylon polymer. The self-lubricating joint has greater flexibility, demonstrating a much higher performance. The team has fitted 43 of these joints to date in India, where the team is conducting field tests to improve their model. With a preliminary goal to mass-produce and distribute 100,000 joints in the next three years, Sadler said he expects the $20 production cost can be driven down further.
Press release: $20 artificial knee for patients in the developing world …
Flashback: Dr. Sethi and the Jaipur Foot