IIT Guwahati researchers have developed a prosthetic leg specifically designed for Indian conditions. It is suitable for uneven terrain and supports Indian needs such as cross-legged sitting, and deep squatting. It is also adjustable for the different age groups and multiple stages of prosthesis use.
This research was funded by the union ministry of education and the department of biotechnology, government of India. IIT Guwahati researchers collaborated with 151 Army Base Hospital, Guwahati, Tolaram Bafna Kamrup district civil hospital, Guwahati, Guwahati Neurological Research Centre (GNRC), North Guwahati, and North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGHRIMS), Shillong.
Prosthesis development in India faces many challenges. Highly functional mobility for amputees requires devices with advanced features which are expansive and cannot be afforded by many.
Further, affordable prosthetics that are available in the market have many functional limitations. In addition, the Indian lifestyle and uneven terrain require prosthetics with specifications unique to India, which are not widely available in the market.
A team led by S Kanagaraj, department of mechanical engineering, IIT Guwahati, set out to tackle these issues. Prototypes of their models developed by this research team are currently undergoing trials.
Highlighting the key areas of their research, S Kanagaraj of IIT Guwahati said: “The knee joint developed by our team has a spring-assisted deep squat mechanism, which helps to use Indian toilet system more comfortably; the knee rotating mechanism helps to have cross-legged sitting; the locking mechanism helps to reduce the fear of falling of patients while walking in unknown terrain; adjustable link length in a knee helps to have either more stability or easy flexing depending on age and requirement of the patients. Overall, the knee joint is designed to meet the Indian lifestyle which other products fail to fulfil”.
The researchers identified the following needs and developed novel solutions:
Need 1: Market products developed with western technology ignore Indian locomotion needs, such as cross-legged sitting, deep squatting for toilet use, and exercise postures in yoga which can be used for rehabilitation.
Solution: Advanced knee rotation mechanism is developed in order to facilitate cross-legged sitting – allowing huge improvement in range over traditional prosthetic knees. The deep squat mechanism helps to prevent the arrest of motion while standing up and reduce metabolic energy cost.
Need 2: Additional stability is required for the patient at multiple stages of prosthesis use. During the initial training of the amputee, it is required for safety concerns and to address the fear of falling. Once the amputee is used to their leg, walking on uneven terrain, sloppy region and staircases are difficult.
Solution: Knee-locking mechanism is provided which can be activated and deactivated by the amputee as they encounter difficult conditions as mentioned above.
Need 3: The prosthesis leg requirements vary according to the residual length of the leg of the patient. In addition, depending on the age of the patient, more stability is required for older patients who are at a higher risk of falling.
Solution: Link length adjustability and prosthesis alignment adjuster mechanism are also provided for customization according to the patient’s need.
Need 4: Difficult terrain significantly hampers the functioning of traditional ankle joints. In addition, during physical activity, dynamic balance is required to prevent the risk of falling.
Solution: Impact load on hard surfaces is reduced, toe-off force is maximized and balance is ensured while walking on difficult terrain.
The abnormality noticed in their gait pattern of knee and foot is reduced using the Sankalp knee design and confirmed using gait and motion analysis. As different parameters such as comfort, weight, and functionality of lower limb prosthesis play an important role in deciding human locomotion, the prosthesis leg is optimized to meet all requirements. The lower limb amputees will have improved quality of life, independence, and comfort level in doing their daily activities.
The prosthetic leg is tested as per international standard loading conditions up to 100 kg body weight.
Reduced weight of prosthetic leg is achieved by selecting suitable polymers, Aluminium alloys and stainless steel for different components.
Cost of around Rs 25000 is ensured using the technology.