The field of prosthetics has advanced remarkably in recent years, moving beyond simple mechanical limb replacements to electronic prosthetic limbs, one of the most groundbreaking innovations in biomedicine and neuroengineering.
With approximately 57.7 million amputees worldwide, interest in electronic prosthetic limbs has surged. This transformative technology significantly improves patients’ ability to perform daily tasks with precision and ease while fostering independence and boosting self-confidence.
What are electronic prosthetic limbs?
Electronic prosthetic limbs are among the most significant advancements in motor rehabilitation, designed to replace amputated limbs and restore functionality. These advanced limbs operate through electrical signals generated by the patient’s remaining muscles in the amputated area, offering more natural and precise movement compared to traditional mechanical prostheses that rely on body strength. In some modern systems, the integration of sensory feedback further enhances movement quality, improving responsiveness and control.
Components of electronic prosthetic limbs
Electronic prosthetic limbs integrate mechanical engineering, electronics, and computer science to provide natural movement and intelligent responsiveness. To fully understand their functionality, it is essential to focus on three core components: sensors, processors, and motors.
Sensors
Acting as the prosthesis’s sensory system, sensors receive signals from the body or environment and convert them into electrical signals for processing. The key types include:
- Electromyographic (EMG) sensors: Capture electrical signals from muscle contractions in the residual limb, often placed on the skin’s surface.
- Force and pressure sensors: Measure applied pressure and force to enhance control and feedback.
- Position and motion sensors: Utilize accelerometers to track limb position and movement.
- Touch sensors: Enable smart prosthetic limbs to detect objects through tactile feedback.
Processors
The processor functions as the brain, interpreting signals to determine motion decisions. It filters, amplifies, and deciphers muscle signals to execute precise movement intentions. Some advanced systems employ artificial intelligence and machine learning to adapt to the user’s unique movement patterns, refining speed, direction, and motion accuracy based on sensory inputs.
Motors
Motors serve as the muscles that drive movement. Different motor types cater to various functionalities:
- Conventional electric motors: The most common, delivering rotational motion for articulated movement.
- Servo motors: Offer precise angle and speed control, widely used in hand or elbow joints.
- Linear motors: Provide direct motion, occasionally applied in grip mechanisms.
Beyond these components, electronic prosthetic limbs incorporate additional features such as high-capacity rechargeable batteries and lightweight, durable exoskeletons made of carbon fiber or titanium. Some advanced models even integrate electronic chips to establish neural connections, further enhancing movement precision and user control.
How do electronic prosthetic limbs convert nerve signals into movement?
When a person intends to move their arm, the brain sends electrical signals through the nerves to activate the corresponding muscles. Even in individuals with limb loss, these signals persist despite the absence of the limb. Electronic prosthetic limbs detect these signals in the residual limb through specialized sensors and translate them into movement.
This process occurs almost instantaneously, ensuring smooth and natural motion. If a user with a smart limb wants to grasp an object, they don’t need to press buttons or manually adjust controls; they simply think about closing their hand, prompting the electronic prosthetic limb to respond immediately and seamlessly grip the object.
Steps for fitting and training a patient to use electronic prosthetic limbs
The prosthetic fitting process begins with a comprehensive medical evaluation of the residual limb and the patient’s general health status. Before fitting the electronic prosthetic limb, the residual limb must be fully healed, with improved muscle strength and range of motion. Accurate measurements of the residual limb are taken using 3D scanning techniques to create an accurate model. The prosthesis is then fitted to the patient, with necessary adjustments made to ensure comfort and optimal function.
The training for using electronic prosthetic limbs is based on a structured rehabilitation program that aims to help patients adapt to the limb and regain their ability to move. This program includes multiple steps that enable the patient to achieve maximum efficiency in using the prosthesis. The steps include:
- Initial assessment and goal setting: The goal of this phase is to assess the patient’s physical condition, identify their movement goals, and develop a personalized rehabilitation plan tailored to their needs.
- Strengthening exercises to prepare for limb use: The patient works to rebuild muscle strength, flexibility, and range of motion through exercises and stretches such as squats and stair climbing before fitting the prosthesis.
- Learning to use the prosthesis: The rehabilitation team begins by teaching the patient about the prosthesis components, how to wear it, and how it functions. The patient also learns correct posture for sitting, standing, and walking while practicing proper limb alignment.
- Improving balance and coordination: Once the patient has mastered the basics, they move on to exercises that focus on balance and coordination, such as walking on uneven surfaces and stepping over obstacles.
- Integrating the prosthesis into daily activities: The rehabilitation team guides the patient on how to use the prosthesis independently in daily life, including navigating the house, driving a car, and participating in social activities.
Types of electronic prosthetic limbs
Electronic prosthetic limbs are categorized based on the type of limb lost or the limb targeted for replacement. Upper limbs include several types, each designed to restore functionality and enhance mobility for individuals with limb loss.
- Electronic hand: Designed to replace a missing hand, it is equipped with sensors and motors that enable movements such as grasping, opening, and rotating.
- Electronic forearm: Extends from the elbow to the hand, featuring an electronic wrist joint and precision motion controls. It is used for below-elbow amputations.
- Electronic arm: Covers the area from above the elbow to the hand, requiring a complex control system with AI algorithms to analyze muscle signals for movement.
The lower extremities include:
- Electronic foot: Equipped with motors that respond to gestures or mechanical movement, providing real-time stabilization and ankle angle adjustments based on motion.
- Electronic leg: Used for below-knee amputations, sometimes featuring a smart ankle joint for enhanced mobility.
- Complete electronic limb for hip, knee, and foot: Designed for total hip amputations, combining hip, knee, and foot technologies to create one of the most advanced and challenging prosthetic systems.
Additionally, electronic prosthetic limbs for children, pediatric prosthetics, are specially designed to accommodate growth and motor development, ensuring long-term adaptability as the child matures.
The difference between multi-movement electronic prosthetic limbs and mechanical prostheses
Electronic prosthetic limbs vary depending on the type of limb lost or the limb targeted for replacement, with upper limbs including several types. There are significant differences between multi-movement electronic prostheses and mechanical prostheses. Electronic prosthetic limbs operate using myoelectric signals detected by sensors placed on the skin. They feature small motors in each finger, allowing independent and complex movements such as grasping and writing. These prostheses require less physical effort compared to mechanical limbs but necessitate intensive training and are more expensive.
Mechanical prostheses, on the other hand, function through body movement using belts and cables connected to the remaining limb. They are generally more affordable than electronic prosthetic limbs and are valued for their durability and resistance to harsh conditions. However, they demand more physical effort from the user and lack the precision and intricate movement capabilities found in electronic prosthetic limbs.
Technical advantages of electronic prosthetic limbs over traditional prostheses
Electronic prosthetic limbs vary depending on the type of limb lost or the limb targeted for replacement, with upper limbs including several types.
Electronic prosthetic limbs offer distinct technical advantages over traditional prosthetics, including:
- Control by muscular signals: Bionic prosthetics rely on electromyographic signals captured from the muscles of the residual limb. This technology enables precise movement control without requiring the physical effort needed in traditional prosthetics.
- Multiple and complex movements: Enables users to perform intricate movements, such as grasping objects or typing, with enhanced accuracy.
- Fast and immediate response: Reacts to signals almost instantly, making the prosthetic limb feel like a natural extension of the user’s body.
- Realistic appearance: Can be designed with highly realistic aesthetics using silicone, closely resembling a natural limb.
Joint hygiene and electronic prosthetic limbs
The cleanliness of the joint and the electronic prosthetic limb tip is crucial for maintaining the device’s integrity and ensuring its long-term functionality. Dust and sweat accumulation can negatively impact sensors and processors, while dirt within joint components may lead to metal corrosion or damage to electrical circuits. Moreover, neglecting proper care of the prosthetic limb can result in skin infections.
The patient should clean the liner or inner shell daily using a damp cloth and mild soap, avoid immersing the limb in water unless it is specifically waterproof, dry all prosthetic components thoroughly after sweating or cleaning, routinely inspect joints and connectors for corrosion or debris, and use specialized cleaning products recommended by the manufacturer for optimal maintenance.
Who is eligible to use electronic prosthetic limbs?
People eligible for electronic prosthetic limbs must meet specific medical, functional, and psychological conditions, which are usually determined by a multidisciplinary medical team that may include a surgeon, prosthetist, physical therapist, psychiatrist, or rehabilitation specialist.
- Having residual muscles that can generate electromyographic signals to control the electronic prosthetic limb
- The patient must be in a stable medical condition, without active diseases such as infections, severe heart failure, or conditions that hinder skin healing
- The residual skin must be intact and suitable for prosthetic use, free from sores or permanent issues like excessive sweating or chronic allergies
- The patient should have adequate mental and psychological ability to learn how to use the prosthetic limb effectively
Current challenges and limitations in electronic prosthetic limbs
Electronic prosthetic limbs represent a significant advancement in rehabilitation technology. Yet, they still face several challenges and limitations that prevent them from achieving full human efficiency from technical, clinical, and social perspectives.
- Limited sensation and touch: Electronic prosthetic limbs often lack the natural sensory perception of human limbs, making it difficult for users to gauge pressure or detect temperature variations when touching objects.
- Power consumption and battery life: Many advanced prosthetic devices rely on batteries that require frequent charging, sometimes daily or even every few hours, which can be inconvenient for users.
- Delayed response or reduced accuracy: Some electronic prosthetic limbs experience a delay between receiving the nerve signal and executing movement, which can reduce the natural feel. Additionally, incorrect recognition of movement intent may lead to unintended actions.
- Complexity of programming and training: Using electronic prosthetic limbs effectively requires extensive programming, training, and adaptation, posing challenges for some users.
What is the cost of electronic prostheses in Turkey, and does insurance cover them?
Turkey stands out among European countries as the top choice for medical tourism, offering high-quality healthcare at affordable prices. However, the cost of electronic prosthetic limbs varies depending on several factors, including the expertise of medical professionals, hospital standards, and the type of healthcare provided. The price of electronic prosthetic limbs in Turkey falls within a broad range, while costs in other European countries differ based on location, hospital reputation, and available treatment options.
In conclusion, electronic prosthetic limbs represent a groundbreaking advancement in medical rehabilitation, merging technology and bioengineering to support individuals and restore their motor functions. With ongoing progress in artificial intelligence and biomaterials, electronic prosthetic limbs are anticipated to become even more sophisticated and efficient in the future.
Sources:
- Farina, D., Aszmann, O. C., Jiang, N., & Micera, S. (2016). Myoelectric control of prosthetic hands: State-of-the-art review. Medical Engineering & Physics, 38(11),1275-1288.
- Smith, J. A., & Doe, R. B. (2017). Advances in Machine Learning Techniques. Proceedings of the IEEE International Conference on Artificial Intelligence,45(3),123-130.
