Below-knee prosthetic leg
A lower limb prosthesis in which the knee joint is preserved, consisting of a socket, a liner and a prosthetic foot.
What is a below-knee prosthetic leg?
A below-knee prosthetic leg, clinically called a transtibial prosthesis, is a lower limb prosthesis used when the amputation has taken place below the knee joint, at the level of the shinbone (tibia). At this level the person's own knee joint is preserved; this is considered an important advantage in terms of walking, balance and energy efficiency.
A below-knee prosthetic leg aims to partially restore the function of the lost foot and lower leg and to support standing, walking and participation in daily activities. Whether a prosthesis is suitable for a person is determined by the physician's assessment, depending on factors such as the cause of amputation, the condition of the residual limb, general health and the expected activity level.
A below-knee prosthesis usually consists of a liner worn over the residual limb, a custom-made socket that holds the residual limb, a tube (pylon) that connects these to the prosthetic foot, and a prosthetic foot that supports walking. The components are not selected individually but as a whole that complement one another.
The cause of amputation can differ from person to person; vascular problems, injuries, infections or congenital conditions may be among them. Whatever the cause, the prosthetic plan is drawn up on the basis of a current clinical assessment and the person's everyday goals.
Basic components
The function of a below-knee prosthesis relies on complementary components working together in harmony. The socket holding the residual limb properly and distributing the load evenly is decisive for comfort and a secure connection. The parts below are planned as a whole.
- Liner: An intermediate layer worn over the residual limb, made of silicone or a similar soft material. It forms a cushion between the skin and the socket and helps distribute pressure more evenly.
- Socket: The custom-made part that encloses the residual limb and connects the prosthesis to the body. It is the main part that determines how the load is transferred to the skin and soft tissues.
- Pylon (tube): A load-bearing intermediate element that connects the socket and the prosthetic foot. It makes it possible to set the length and alignment of the prosthesis.
- Prosthetic foot: The component that provides ground contact, balance and push-off during walking; it is selected according to the person's activity level.
- Suspension system: The method of attachment that keeps the prosthesis securely on the residual limb.
The advantage of preserving the knee joint
Having the knee joint preserved allows the person to use their own knee movement. This can contribute to a more natural gait, make movements such as sitting down and standing up, bending and using stairs easier, and generally lead to lower energy expenditure.
A person who can use their own knee can manage balance and changes of direction with the feel of a natural joint. Even so, the function achieved varies from person to person depending on the length and condition of the residual limb, muscle strength, general health and the rehabilitation process.
Socket types and suspension methods
The socket is the main component that determines how the residual limb carries the load. Different designs aim to distribute the load to different areas of the residual limb or to enclose the residual limb over a wider surface. The suitable socket design is planned taking into account the shape of the residual limb, sensitive areas and the condition of the skin.
Different suspension methods can be used to keep the prosthesis on the residual limb. These include a mechanical locking connection via the liner, systems based on vacuum (suction) and sleeve-like external retention solutions. The method is chosen according to the person's activity level, variability in residual limb volume and comfort requirements.
Good suspension helps the prosthesis move with the residual limb during the step without separating from it and contributes to a feeling of safer walking. Determining the suitable method often involves a trial process; the person's feedback is valuable at this stage.
- Socket designs that aim to distribute the load to specific areas of the residual limb or over a wide surface
- Suspension methods using a lock via the liner, vacuum, or an external sleeve
- The choice is made according to the shape of the residual limb, the condition of the skin and daily activities
Residual limb care and skin health
When using a below-knee prosthesis, the health of the residual limb and skin is important for comfort and continued use. Because the skin is in contact with the socket and liner all day, regular cleaning and observation are recommended. Keeping the residual limb and liner dry and clean helps reduce the risk of irritation.
In the case of symptoms such as redness, irritation, pressure marks, blisters or persistent pain, you are advised to stop using the prosthesis and consult the practitioner or physician. Because residual limb volume can change in the early period, the fit of the socket may be reassessed over time.
The first prosthesis and the temporary-definitive prosthesis process
After amputation, volume changes occur in the residual limb as the edema resolves and the tissues take shape. For this reason, the process usually begins with a temporary (initial) prosthesis. The temporary prosthesis helps the person stand up and begin walking early while also supporting the maturation of the residual limb.
When the shape and volume of the residual limb have reached a certain stability, a custom-made definitive prosthesis is planned. The timing of the transition is determined according to the rate of healing, the condition of the residual limb and the physician's assessment. With the definitive prosthesis too, socket adaptations or component adjustments may be needed over time.
Gait training and rehabilitation
Fitting the prosthesis is the beginning of the process; effective use depends largely on rehabilitation. Gait training usually begins with balance and weight-shifting exercises; using parallel bars and, when necessary, walking aids, the person progresses gradually toward independent walking.
The rehabilitation program aims to improve muscle strength, balance and coordination, to establish a correct gait pattern and to teach residual limb care and prosthesis use. The program is planned individually under the guidance of the physiotherapist and the relevant team. Results vary from person to person.
Daily life and return to activity
The basic aim of a below-knee prosthesis is to support participation in daily activities. Over time and with rehabilitation, many people can take part again in movement around the home, walking, work and social activities. The extent and pace of the return to activity differ according to the person's general condition, motivation and the components selected.
The prosthetic foot and other components are selected according to the activity level the person is aiming for. Regular follow-up and, when necessary, adaptations help make the use of the prosthesis in daily life sustainable. Activity plans are made under the guidance of the physician and practitioner.
During this process, it can be useful to set realistic goals and assess progress step by step. As the time spent with the prosthesis increases, the person's confidence and familiarity also develop; for this reason, patience and regular practice are a natural part of the process.
What is considered in choosing the right components?
Activity level
The targeted activity level, from moving around the home to a more active life, guides the choice of socket and prosthetic foot.
Condition of the residual limb
The length, shape, sensitive areas and skin condition of the residual limb are decisive for the socket design and suspension method.
Socket fit
Adaptations and liner adjustments may be needed in line with volume changes that can occur in the residual limb over time.
Skin health
In the case of redness, irritation or pressure marks, it is recommended to stop using the prosthesis and consult the practitioner.
Balance and confidence
Balance, stability and a sense of confidence are criteria as important as comfort in choosing components.
Follow-up and maintenance
Regular check-ups help maintain the fit and function of the prosthesis.
What observations should you share during the socket fitting?
During the fitting appointment, rather than giving only a general assessment of comfort, describe what you feel and during which movement it occurs. These notes can help your practitioner assess the socket and suspension fit.
- Where exactly, and during which movement, do you feel pressure or friction?
- Does the sensation change when sitting, standing up and walking?
- Do you feel movement inside the socket during a step, or any insecurity about how the prosthesis stays on?
- At which stage of putting on and taking off the liner and prosthesis do you need help?
The fitting process
Physician's Prescription / Medical Report
The fitting begins with a specialist physician's prescription/medical report.
Assessment and Measurement
The residual limb is assessed; measurements are taken for custom-made production and the components are planned.
Production and Trial Fitting
A custom-made socket is produced; fit and alignment are adjusted during the trial fitting.
Fitting and Training
The prosthesis is fitted; training is given on its use and on residual limb care.
Follow-up and Adaptation
Regular follow-up is provided; when necessary, socket and component adjustments are made.
Frequently asked questions
Can you climb stairs with a below-knee prosthetic leg?
Preserving the knee joint allows the person to use their own knee movement in situations such as stairs and slopes. Individual results vary according to activity level and rehabilitation.
When can I start using my first prosthesis?
The starting time depends on the healing of the residual limb and the physician's assessment. The process usually begins with a temporary prosthesis; as the residual limb takes shape, a definitive prosthesis is planned.
What happens if the size of the residual limb changes?
Residual limb volume may change, especially in the early period; you are advised to consult the practitioner for socket adaptation or liner adjustment.
How long can I wear the prosthesis each day?
The daily duration of use varies according to the person and the condition of the residual limb; the pattern of use is determined gradually under the guidance of the rehabilitation team.
What should I do if I get redness or irritation on my skin?
In the case of persistent redness, irritation, blisters or pain, you are advised to stop using the prosthesis and consult the practitioner or physician.
Do I choose the prosthetic foot myself?
Components are selected jointly through the assessment of the physician and the practitioner, according to activity level, the condition of the residual limb and goals.
This content is for information purposes; please consult your physician for diagnosis and treatment. Fittings are carried out at our licensed center locations in line with a specialist physician's prescription/medical report.