Prosthetist sitting at a table and talking to a leg amputee who shows his residual limb with a liner on

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Prosthetic Fitting

Learn more about preparing your patient for their first prosthetic fitting and restoring their mobility. Find out more about how to explain the components of prosthetic legs.

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Prosthetic Fitting

Restoring your patient's mobility

After the acute phase of your patient's recovery, they will be ready to move on to the next key step in their rehabilitation: being fitted for a prosthesis and learning how to walk on it.

They’ll typically begin that process with an initial prosthesis manufactured during the post-operative period after their surgical wound has healed. Most patients will use their initial prosthesis until the volume and musculature of their residual limb have both stabilised.

This period gives your prosthetic team an opportunity to explore the optimal socket fit and identify the right components for their final prosthesis.

Male person sits at a table opposite a female person and listens to her while she points to a document

Components of a prosthesis

When it comes to selecting components for a lower-limb prosthesis, your prosthetic team can choose from a wide variety of products, construction techniques, and functions. The right combination for each patient will differ depending on their amputation, residual limb, and physical capability.

The two most common lower limb amputations - transtibial (TT) and transfemoral (TF) - typically require some combination of the following components:

A prosthetic socket that creates a secure, comfortable connection between the patient’s residual limb and their prosthesis
A socket liner and suspension system keeps the prosthesis in place while the patient is walking
A prosthetic knee joint (TF only) that helps control the patient’s gait and stance
A prosthetic foot (TT and TF) that provides safety and stability while the patient is standing or walking
Adapters that help keep the patient’s prosthesis in position during daily activities
Covers change the look of a prosthesis, either to look more natural and blend in with a patient’s overall look, protect their prosthesis, and/or feature a personalised design the patient has chosen.

The prosthetic socket

This critical component forms the connection between the amputee's residual limb and the rest of their prosthesis. Each socket is built specifically for its wearer, usually using light, durable materials like carbon, silicone, or lamination resin.

The socket has three critical functions that help ensure a safe, comfortable walking experience:

Supporting load transfer and ensuring that axial forces are evenly distributed when the user is walking
Stabilising the user by absorbing horizontal forces that can otherwise cause the residual limb to tilt back and forth in the socket
Adhering to the user to ensure a firm, consistent connection between the residual limb and socket during swing phase

Ottobock Kenevo microprocessor knee user sitting on a couch and adjusting his Varos socket

Socket liner & suspension system

These two components define the connection between the user’s residual limb and prosthetic socket. Together, they ensure that the socket doesn’t slip off the user’s residual limb while walking.

Suspension systems usually work with specific liners and are typically designed to work in one of two ways: either through negative pressure (a vacuum seal) or using a mechanical setup. The right system for each user often depends on the shape and height of their residual limb.

Amputee standing in front of a prosthetist and donning an Ottobock Skeo Sealing liner

The prosthetic knee (TF only)

This replacement joint is a critical component of any prosthetic solution for users with an above-knee amputation. Prosthetic knees come in multiple different formats, but typically fall into one of three groups defined by how the joint functions under load:

No flexion under load, e.g., locking/brake knees, 4-axis polycentric knees, mechanical monocentric knees with no stance control mechanism
Limited flexion under load, e.g., bouncing adapters, polycentric knees with 4+ axes (Ottobock 3R60)
Unlimited flexion under load, e.g., knees with hydraulic stance phase safety (Ottobock 3R80), microprocessor-controlled knees (Kenevo, C-Leg, Genium, Genium X3)

2 people sitting on a park bench, one person wearing an Ottobock Kenevo microprocessor knee

Comparing prosthetic knee options

While these components offer a variety of different functions, designs, and capabilities, it’s always best to start with the user’s mobility, lifestyle, and activities when selecting a knee joint for their prosthesis.

Individually adjusted by a prosthetist , each kind of prosthetic knee offers different benefits for the user to consider during the selection process. For example:

Mechanical monocentric knee joints function in a basic, straightforward way that makes it easy for patients to initiate stance and swing phase.
Polycentric knee joints (4+ axes) offer enhanced safety when the knee is optimally aligned. During swing phase, these knees can reduce leg length in a way that increases the user’s toe clearance.
Microprocessor knee joints maximise users’ security and confidence by dynamically stabilising them during stance phase, enhancing control during swing phase, and offering responsive support when starting to walk and descending stairs and slopes.

The prosthetic foot (TT and TF)

Another key component of any lower-limb prosthesis is the prosthetic foot. This component plays an important role in stabilising the user when they’re standing or walking. Today’s prosthetic teams can choose from a wide variety of feet that support different gait styles, daily activities, and other additional user needs.

Ottobock Trias footshell next to a Ottobock Trias prosthetic foot

Comparing prosthetic foot options

Several different characteristics of a prosthetic foot can affect how well it performs for a specific user. A few important factors to consider are:

Ankle functionality: A foot may function very differently depending on whether its ankle is movable or not. Non-movable ankles can be made from a variety of different materials (e.g., carbon fibre or fibreglass) with different flexion characteristics that influence how the foot feels during initial contact, mid-stance, and terminal stance.
Stiffness: This property of both the heel and forefoot can impact how dynamically the foot responds throughout the gait cycle. Heel stiffness is especially important for establishing safe initial contact, when users must safely transfer energy to the foot so it can be released at toe-off. Some feet optimise this process with moulded carbon fibre heel plates that function as a highly effective, energy-capturing spring.
User footwear: For safety, lower-limb amputees should avoid footwear with slippery soles and uneven heel heights. Heels should also be firm but not too stiff, so the user can softly roll over during walking while still maintaining control of their prosthesis. Some prosthetic feet also feature adjustable heel heights that can give users more options when choosing appropriate shoes.
Cosmetic preferences: While some amputees may like to show off their prosthesis, others will prefer a more natural and discreet look. A wide range of cosmetic covers are available for users who want their prosthesis to blend in with their overall look.

Adapters

These components can serve a variety of functions on a lower limb prosthesis. Some adapters help ensure that a user’s prosthesis remains correctly positioned as they move through their day. Other specialised options, like rotation adapters, can give users better control of their prosthesis during some everyday activities (e.g. when getting dressed).

Person sitting on a stool connecting Ottobock Quickchange adapter to the Trias prosthetic foot

Cosmetic covers

While some amputees may like to show off their prosthesis, others will prefer a more natural and discreet look. A wide range of cosmetic covers are available for users who want their prosthesis to blend in with their overall look.

Smiling women wearing a prosthetic leg with an Ottobock cover for modular transfemoral prostheses holds a shoe while another woman kneels in front of her and holds the other shoe for her

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