Walking tall From the makers of the Jaipur Foot — in collaboration with students from Stanford University — comes another marvel: the Jaipur Knee. It mimics the movement of a natural joint and costs less than Rs 1,000. Anjana Jha reports on this grassroots invention that has been ranked one of the best in the world An inexpensive knee joint — selected by TIME magazine as one of the 50 best inventions in 2009 — promises to help thousands of amputees who cannot afford expensive artificial joints. Costing just $ 20, the Jaipur Knee was designed by students from Stanford Engineering in collaboration with Rajasthan-based Bhagwan Mahaveer Viklang Sahayata Samiti (BMVSS), the NGO that made the Jaipur Foot a household name. THE BACKGROUND STORY During a lecture tour to San Francisco in January 2007, D R Mehta, founder and chief patron of BMVSS, screened a film at Stanford University showcasing its work in the area of prosthetic limb design. It aroused keen interest. On another visit, Mehta met the vice-dean and other professors; an informal decision was made to initiate a collaborative project to design a stable, flexible, and inexpensive knee joint to replace the unstable and restrictive singleaxis joint that BMVSS was using with the Jaipur Foot. In November 2007, Stanford University and BMVSS signed a memorandum of understanding during Mehta’s visit to San Francisco to receive the ‘Technology Benefiting Humanity’ award from The Tech Museum of Innovation. “I suggested we design a new knee joint for those whose legs were amputated above the knee,” says Mehta. “This new joint, we hoped, would provide a natural and energy-efficient gait, a good stance, the ease of progression, stability and flexibility.” The idea of refining the existing polycentric design — prohibitively expensive for the common man, complexly designed and heavier — was readily accepted. After Stanford professors visited the BMVSS workshop in Jaipur, a team of four postgraduate students was set up in January 2008. THE MAKING During the next few months, the team made two one-week visits to the artificial limb fitting facility in Jaipur to gain technical information from the technical committee and feedback from patients. Under the guidance of two Stanford professors, the team took about eight to nine months to design the new knee joint. The first prototype was fitted on a few patients at BMVSS in August 2008. Based on user feedback, several changes were made and the final product — though ongoing research for further refinement continues — was ready in October 2008. The detailed report and a computerised design were handed over to BMVSS. To date, it has been satisfactorily used on 500 patients. The Jaipur Knee has an upper and a lower body linked by two side linkages and one mid-linkage. It is manufactured in a CNC (computer numerical controlled) machine where the end-to-end component design is programmed to exact specifications. This also makes mass production possible. THE OLD AND THE NEW “Owing to the challenge posed by prosthetic knee replacement, the most important distinction in lower limb amputation is whether the knee joint has been preserved or not,” says Dr Pooja Mukul, technical consultant at BMVSS. Most above-knee amputees are fitted with the simple single-axis knee joint because it is the only affordable option. Even BMVSS used it before it developed the Jaipur Knee. “Made of metals and polymers, the single-axis knee joint presents gross limitations in gait performance, stability, energy consumption, negotiating inclines and squatting,” adds Dr M K Mathur, chief technical consultant at BMVSS. “In comparison, a polycentric design offers both flexibility and stability,” says Dr Mukul. “Owing to the four-bar linkage system developed by kinematics and mechanism design expert C W Radcliffe about 50 years ago, the polycentric knee moves through a different axis during different phases of the gait cycle.” However, in its earlier avatar, the polycentric design was heavy, complex and expensive. All these problems have been tackled in the new design. Made with oil-filled nylon 6 — a readily available material — it is self-lubricating and makes joint movements smooth. THE USERS “Only 24 patients between 51 and 60 years and six patients in the 61-plus age group have been fitted with the new knee joint in the past year,” informs Dr Mukul. “That’s because the incidence of amputation in Indians aged 50 years and above is less than 10 per cent. Some elderly amputees prefer using wheelchairs. Technically, we do not expect any difference in the performance of elderly patients using this joint although gait training may take longer.” Amputees receive two days of gait training when they relearn balancing, weight shifting and taking correct step lengths. Ghaziabad-resident Ashish Oswal, 42, was one of the people to be fitted with the Jaipur Knee in August 2008. After walking earlier with a single-axis knee joint following a road accident in 2007, Oswal is delighted with the flexibility and confidence the new joint offers him. The single-axis design lacked a locking system and hence constantly made him feel unstable. “I felt safer using a stick,” he says. “This new joint gives me better stability and gait.” However, owing to wear and tear, his knee had to be replaced last month. “The friction caused by the screws damages the polymer body; BMVSS is trying to rectify the problem.” Surjeet Singh, 58, from Tarn Taran district in Punjab was fitted with the new knee in December 2009. He says, “After a road accident, I never thought I could stand again, let alone walk.” Fifty one year-old Juman Mohammed — another road accident victim — brims with the same confidence. “It has taken me practically no time to walk again,” says the resident of Moradabad in Uttar Pradesh. “I don’t think it will be very long before I can run again!” THE FUTURE Commenting on a report that it is the preliminary goal of BMVSS to produce and distribute 100,000 joints in the next three years, Mehta says, “We would like maximum number of people to benefit from it. Other institutions could also use this joint. This, of course, will depend on the dissemination of information about the efficiency and affordability of the joint.” In 2008-09, BMVSS — the largest limb and caliper fitting organisation in the world — provided 18,923 patients with artificial limbs. As almost one-third of this comprises above-knee amputees, fitting the new knee on 100,000 people could be a distinct possibility. Continuous upgradation of technology has greatly enhanced the quality of life of the physically challenged. The Stanford team will soon launch an elbow joint and are working on a wrist joint. Without a doubt, there will soon be other low-cost joints sharing the success story. Featured in Harmony Magazine January 2010