What is a Prosthesis?

Prosthetic limbs are engineering prostheses that are specifically designed and fabricated to compensate for amputees or limbs with incompletely damaged limbs, also known as "prosthetic limbs". Its main function is to replace part of the function of the limb and enable the amputee to restore a certain degree of self-care and work ability. It is applicable to amputees due to diseases, traffic accidents, work-related injuries, sports injuries and other reasons.

Chinese name: Prosthesis
nickname: Prosthetic

Suitable: Amputee
Function: Instead of losing part of the function of the limb

Classification of prostheses

Classification of prosthetics. Prosthetics can be classified by structure, function, assembly time, amputation site, source of power, and selected materials. But the most common classification method is to divide the upper limb prosthesis and lower limb prosthesis according to the amputation site.

Upper limb prosthesis

The materials used to make prosthetics are mainly aluminum plates, wood, leather, plastic and metal mechanical parts. A good prosthesis must have conditions such as good function, comfortable and convenient wearing, light and durable, and appearance similar to healthy limbs. Among the many prostheses we use, there are many different classifications and names according to the purpose, location, and control system of the prosthesis. The following will briefly introduce the commonly used and more advanced prostheses.

(1) Decorative upper limb prosthesis: This kind of artificial limb does not have the function of self-care in work and life. Its main role is to make up for the appearance of the upper limb and maintain the balance of the limb. Mainly used for upper arm amputation and severance of the shoulder and scapular belt.

(2) Tool hand: It is specially designed and manufactured for upper limb amputees. It mainly consists of two parts. One is an arm barrel installed on the residual limb. The arm barrel is fixed on the residual limb. The end of the arm barrel is provided with a tool adapter. The second is a variety of labor tools and household appliances, such as hammers, screwdrivers, frustration knives, multi-purpose hooks and other labor tools, toothbrushes, spoons and other household appliances. Through the adapter, various tools and living appliances can be replaced at any time according to needs, and the working ability and self-care ability of the patient can be restored to a certain extent. However, the tool hand does not have the normal shape of a human body, and the range of use is also very limited.

(3) Traction mechanical prosthesis: This prosthetic hand is also called mobile prosthetic hand and mechanical prosthetic hand, which is a substitute for human hand. This artificial hand relies on the coordinated action of the user's own residual and healthy limbs, drives the traction rope, manipulates and controls the opening and holding of the artificial hand, and realizes the action of grasping and extracting objects. This kind of artificial hand is mainly suitable for the disabled forearm and upper arm. Because it is simple in construction, reliable in performance, easy to master, easy to use, and low in price, it is widely used in China.

(4) Electric prosthetics; electric prostheses are externally powered prostheses, which rely on a small electromechanical drive system to complete the predetermined movements of the joints of the prosthetic hand, so that the disabled can basically meet their own life and participate in appropriate work. This kind of prosthesis is suitable for people with forearm or even full arm defects.

Electric prosthesis is composed of electromechanical drive system, control system and housing. The electromechanical drive system relies on micro-batteries to provide energy. The control system relies on pressure micro-switches to switch circuits and send out control information to operate the electromechanical drive system to complete actions. The shell is the shape of the entire prosthesis.

(5) Myoelectric prosthesis: Myoelectric prosthesis is an externally powered prosthetic limb directly dominated by the nerves of the brain. It is the product of modern high science and technology such as precision machinery, micro-electronics technology, materials science and physiology. This prosthetic control system uses the brain nerves to innervate the muscles of the limbs to contract and generate myoelectric signals when they are in motion. The signals are transmitted to the surface of the skin. After receiving the signals, the control system drives the micro-motor to generate motion. It can generally perform three sets of motions: finger flexion, wrist flexion, and wrist rotation. When it is used, it has strong intuition and good bionic effect. It is the development direction of modern prosthetic limbs and is suitable for the disabled with fore hip defect.

This is a kind of upper limb prosthesis that is more advanced in the world at present, it is driven by external force source completely. A battery is placed on the prosthesis to provide energy for its movement. By consciously contracting muscles, amputees can generate a tiny potential difference on the surface of the skin of the residual limb. This voltage can be used to control the function of the prosthesis to open, close and rotate.

(6) Voice-activated prosthesis: Voice-activated prosthesis is an externally-powered prosthesis that uses language as a control signal. This kind of prosthesis is characterized by a lot of human language signals, so it also produces a lot of movements, and it is relatively easy to meet the needs of people with disabilities to take care of themselves. Its advantage is that it is not limited by the degree of disability and the length of amputation of patients with amputees, and is especially suitable for disabled people with upper arm, full arm, or both arms, as well as thigh and leg amputations. However, its disadvantages are that it is easy to be restricted by environmental factors because it needs to make a sound to control the prosthesis, and it is also easy to be interfered by other people's language.

Lower limb prosthesis

Walking is the most basic function of the lower limbs of the human body. Amputation of any plane of the lower limbs (except toes) will cause difficulty in walking. Poor walking posture can also greatly disrupt a person's overall aesthetics. Therefore, the lower limb prosthesis is also designed to restore the normal walking posture of the person as much as possible. At present, lower limb prostheses can be divided into several categories according to the different amputation planes of the lower limbs: foot and ankle prostheses, calf prostheses, thigh prostheses, and hip joint prostheses. Regardless of the level of the amputated prosthesis, it can achieve the purpose of supporting the body and walking.

(1) Hip joint prosthesis: suitable for patients with hip amputation or patients with short thigh stumps.

(2) Foot and ankle prosthesis: suitable for patients with foot and ankle amputation.

(3) Thigh prosthesis

Foam decorative jacket, realistic shape, full contact receiving cavity, advanced joint design, perfect gait.

(4) calf prosthesis

Recent developments in prosthetics

Internationally, with the advancement of society and science and technology, prosthetic technology has continued to develop from low-level simple to high-level complex. In order to improve the practical performance of prosthetics, people have made use of all available contemporary science and technology to create better-performing prosthetics. , Use more advanced technology and materials to make it have more complete performance. Since the 1990s, prosthetic technology has evolved towards more sophisticated, more comfortable, and more personally demanding high-tech directions.

China's prosthetic technology has also achieved some results in the research and development of new structures, new materials, and new technologies. For example, the electromyography prosthesis started in the 1960s. At present, a practical series of electromyographic prosthetics has been formed. In the 1990s, a lower limb with a hydraulic system was developed, a lower limb prosthesis made of composite materials was developed, and an intelligent lower limb prosthesis was researched using electrorheological fluid. Tsinghua University studied the swing using the electromyographic signal for road condition recognition. Phase control of intelligent prostheses and real-time detection of human motion images; China has started to produce some titanium alloy connectors and joints with quality close to the international level; in addition, the development of simple leg prosthetics for remote amputees has been successful. However, in terms of the overall situation of prosthetics in China, there are fewer new technology products, and there is still a large gap in terms of specifications, varieties, performance and quality compared with the world's industrial development countries. The most important thing is the lack of national long-term development planning and focus. High-tech investment. Prosthetic limb assembly requires experts who have the expertise and ability to uniquely apply and develop these products, and should have a high-level, high-level research and development team. In the promotion and application of high-tech prosthetic products, focus on the development of "fist products" with good performance and high quality, which can replace imported prosthetics. Boldly borrow and introduce new foreign structures, new materials and new technologies, and plan and divide labor. There are choices and priorities. China's prosthetic industry "three

"New" research and development should focus on narrowing the gap in production technology and service quality, and strive to catch up with the international level. Priority should be given to the replacement of prosthetic products that are in high demand and generally affordable, and focus on development and production applications A wide range of specialized high-tech prosthetic products that are convenient for centralized production and quick-response standard parts of the prosthesis; complete the development and production of various joints and connectors of the skeletal lower limb system, making its modern prosthetic products fully domesticable In terms of high-tech product development, breakthroughs have been made in new materials such as titanium alloys, carbon fiber composite materials, silicone rubber, and thermoplastic sheet materials. Individual products have reached international synchronization and promoted the industrial structural upgrade of the prosthetic industry.

Extended Prosthetic Reading

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4. Zhang Genglin, Jin Baoshi, and Zhang Yuguang. Overview of human lower limb prosthesis development. Journal of Jiamusi University, September 2002, Volume 20 Number 3: 347-351

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