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IT takes steps to help people with joint disorders

December 10, 2004

A new generation of devices to help people with joint disorders walk with ease and comfort are becoming a reality thanks to the work of GAIT, which is creating the world's first 'intelligent' mechanical devices to support knee and ankle joints.

Due to end in August next year, the 36-month IST programme project is developing the most advanced leg supports designed to date, combining biomechanics with information technologies to produce more comfortable and effective devices that could benefit millions of people across Europe.

"The orthoses we are working with are apparatus that are attached to the leg to support the knees and ankles of people who have joint dysfunctions or lack muscle strength," explains project coordinator José Luis Pons at the Instituto de Autom'¡tica Industrial (IAI) in Spain. "Traditionally they [orthoses] are purely mechanical devices that provide rigidity to the leg when a patient is standing and allow it to flex when they are walking."

Traditional devices, which rely exclusively on mechanical components, are often uncomfortable to wear and though they provide necessary support they do not necessarily allow patients to walk normally and with ease. The four GAIT partners are overcoming those problems by incorporating IT into orthoses, creating intelligent devices that adapt to the way patients' move and the activities they perform.

Added intelligence through IT
"The orthoses we are designing are unique because they contain electronic sensors and actuators to monitor joint movement and adapt the orthosis to it," Pons says.

Each leg orthosis contains two sets of sensors, one to measure the force being exerted by the patient's movements on the joint and the other to determine the pressure being exerted on the patient's leg by the orthosis itself. The actuators use the data obtained from the sensors to set and reset the movement parameters of the mechanical components of the orthosis, thereby allowing the patient to move more naturally.

"Without the incorporation of sensors and actuators, traditional orthoses often cause people to walk abnormally resulting in higher energy use and greater discomfort, something that is a significant problem especially for the elderly," Pons notes. "With this intelligent system patients should be able to move more naturally because the device can react to the activities they are performing, providing them with greater comfort regardless of whether they are sitting, standing, walking or going up stairs."

Besides giving the patient support, the mechanical components of the orthosis are designed to assist movement by acting much like a healthy joint, returning the energy from the patient's stride to the leg and reducing the restrictions to movement. The sensors also monitor the comfort levels of the patient, a critically important issue given that orthoses are often attached to patients' legs for long periods of time.

"Because orthotic devices are attached tightly around the joints it is important that they are set correctly to ensure maximum comfort and reduce the risk of friction which could cause ulcers and sores when the patient sweats or when the weather is hot and humid," the coordinator explains.

All the data collected by the sensors are stored in microchips in the orthoses which can be accessed and controlled wirelessly by doctors. The measurements allow specialists to accurately monitor how well the patient is responding to treatment and to adjust the movement parameters of the device with high precision and therefore better adapt it to patients' needs.

Prototypes take steps towards expanding market
The project partners have so far developed several prototypes of their intelligent orthoses and have tested them on healthy people. According to Pons, the project is planning to run clinical trials with around a dozen patients in Spain and The Netherlands from next March as one of the final steps toward developing a commercially available variant of the system.

The project coordinator expects the GAIT devices to be particularly beneficial to anyone with movement problems caused by neurological disorders or diseases such as arthritis, polio or even strokes. In Europe alone more than 100 million people are estimated to suffer from some form of arthritis in many cases affecting their knee and ankle joints, making it one of the leading causes of disability across the continent.

"A preliminary evaluation of the market shows that these orthoses could benefit a huge number of people of any age and with a wide range of disabilities," Pons says. "In addition, because Europe has an ageing population the incidence of age-related disabilities, such as arthritis, is likely to increase."

With GAIT arthritis sufferers and people with other joint and muscle disorders are likely to regain much of the freedom of movement their disability has claimed from them, potentially allowing millions of people to live a more comfortable and active life.

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