Above-Knee Prosthesis: How to Put On & Use Your Transfemoral Prosthesis

Learning to put on an above-knee prosthesis correctly is essential for comfortable, safe mobility after a transfemoral amputation. This comprehensive guide covers the complete donning process, from preparing your residual limb to verifying proper fit. With the right technique and regular practice, most people can independently don their prosthesis in just a few minutes, enabling confident walking and daily activities.

What Is an Above-Knee Prosthesis?

An above-knee prosthesis, also called a transfemoral prosthesis, is an artificial limb designed to replace the leg above the knee joint. It consists of a custom-fitted socket that connects to your residual limb, an artificial knee mechanism, a pylon (shin component), and a prosthetic foot. Together, these components restore walking ability and help you return to daily activities after a transfemoral amputation.

Above-knee prostheses represent sophisticated medical devices that have evolved significantly over the past decades. Modern prosthetic technology incorporates advanced materials such as carbon fiber, titanium, and specialized silicone to create lightweight yet durable artificial limbs. The prosthesis must account for the loss of the natural knee joint, which means including a mechanical or computerized knee mechanism that provides stability during standing and controlled movement during walking.

The socket is the most critical component of any prosthesis because it forms the interface between your body and the artificial limb. For above-knee amputees, the socket must distribute body weight comfortably across the residual limb while providing secure attachment for walking, running, and other activities. Socket design has advanced considerably, with options including ischial containment sockets that capture the sitting bone for stability, and subischial designs that provide a more natural feel.

Understanding the components of your prosthesis helps you don it correctly and recognize when something isn't right. The liner creates a comfortable interface with your skin and often includes the suspension mechanism. The socket holds everything together and transfers your body weight to the prosthetic components below. The knee mechanism ranges from simple mechanical joints to sophisticated microprocessor-controlled units that adapt to your walking speed and terrain.

Main Components of an Above-Knee Prosthesis

• Prosthetic liner: A cushioned sleeve, typically made of silicone or gel, that fits directly over your residual limb to provide comfort, skin protection, and often serves as part of the suspension system
• Socket: A custom-molded rigid or semi-rigid shell that fits over the liner and residual limb, distributing your body weight and connecting to the prosthetic components
• Suspension system: The mechanism that keeps the prosthesis securely attached, including options like pin lock, suction, vacuum, or belt suspension
• Knee mechanism: An artificial joint that provides stability and controlled movement, ranging from mechanical to computerized designs
• Pylon: The structural component connecting the knee to the foot, typically made of lightweight materials like aluminum or carbon fiber
• Prosthetic foot: The terminal component that provides ground contact, shock absorption, and energy return during walking

How Should You Prepare Before Putting On Your Prosthesis?

Proper preparation before donning your above-knee prosthesis is essential for comfortable, problem-free wear. Start by thoroughly inspecting your residual limb for any skin problems, then clean and dry your skin completely. Gather all necessary supplies including your liner, socks, and prosthesis, and find a stable seated position for the donning process.

The preparation phase is often overlooked but represents one of the most important steps in successful prosthetic use. Taking a few extra minutes to prepare properly can prevent hours of discomfort, skin problems, or the need to remove and redon your prosthesis later in the day. Rehabilitation specialists emphasize that consistent preparation habits lead to better outcomes and fewer complications over time.

Your residual limb undergoes constant changes in volume, skin condition, and sensitivity. These changes can occur daily, seasonally, or in response to activity levels, weight fluctuations, medication changes, or health conditions. By carefully examining your limb before each donning, you become attuned to its normal state and can quickly identify potential problems before they become serious.

The skin-prosthesis interface is particularly vulnerable to breakdown because of the pressure, friction, and moisture that accumulate during prosthetic use. Even minor skin irritation can progress rapidly to blisters, ulcers, or infections if not addressed promptly. Prevention through careful preparation is far more effective than treatment after problems develop.

Inspecting Your Residual Limb

Before each donning, conduct a thorough visual and tactile inspection of your entire residual limb. Use a mirror if necessary to see all surfaces, including the posterior and distal areas that are difficult to view directly. Look for any changes from your normal baseline, including color changes, swelling patterns, or new marks from the previous day's prosthetic wear.

Pay particular attention to areas that receive the most pressure from your socket. For above-knee prostheses, common pressure areas include the ischial tuberosity (sitting bone), the distal end of the residual limb, and bony prominences along the femur. Redness in these areas that resolves within 15-20 minutes of removing the prosthesis is normal; redness that persists longer or that appears darker or discolored warrants attention.

Cleaning and Preparing Your Skin

Clean skin is essential for preventing bacterial or fungal infections that can develop in the warm, moist environment inside a prosthetic socket. Wash your residual limb with mild soap and water, then rinse thoroughly to remove all soap residue. Residual soap can cause skin irritation and may interfere with liner adhesion.

After washing, dry your skin completely using a clean towel. Moisture trapped between your skin and the liner creates conditions favorable for skin breakdown, bacterial growth, and uncomfortable sliding or pistoning of the prosthesis. If you tend to perspire heavily, your prosthetist may recommend antiperspirants specifically formulated for prosthetic use.

Avoid applying lotions, oils, or moisturizers immediately before donning your prosthesis, as these products can interfere with liner grip and suspension. If your skin requires moisturizing, apply products at night after removing your prosthesis, allowing complete absorption overnight. Some specialized products are designed for prosthetic users and can be discussed with your rehabilitation team.

Gathering Your Supplies

Before beginning the donning process, ensure all necessary supplies are within easy reach. This prevents the frustration and potential safety issues of having to move around partially donned with your prosthesis. Your supply checklist should include your prosthetic liner (clean and in good condition), prosthetic socks if you use them, your prosthesis, and any accessories such as a pull sock or donning aid.

Check your liner before each use for signs of wear, including thinning areas, sticky spots, or loss of elasticity. Inspect the suspension mechanism whether it's a pin, valve, or seal to ensure it's functioning properly. A compromised liner or suspension system can fail during use, creating safety risks.

How Do You Apply the Prosthetic Liner Correctly?

To apply a prosthetic liner correctly, turn it inside out to the halfway point, position the distal end at the bottom of your residual limb, then gradually roll it up while smoothing out any air pockets or wrinkles. The liner should fit snugly without gaps, with the suspension mechanism (pin or valve) centered at the distal end. Proper liner application is critical for comfortable wear and secure suspension throughout the day.

The prosthetic liner serves multiple essential functions that make it one of the most important components of your prosthetic system. It provides cushioning between your skin and the rigid socket, distributes pressure more evenly across your residual limb, protects your skin from shear forces and friction, and in most systems, forms the basis of the suspension that keeps your prosthesis attached. Understanding these functions helps you appreciate why careful liner application matters so much.

Different liner materials have different properties that affect how they're applied and how they perform. Silicone liners tend to be more durable and provide excellent grip, but they can be more difficult to roll on. Gel liners offer superior cushioning and are often easier to apply, but they may not last as long and can feel warmer. Your prosthetist selected your liner type based on your specific needs, activity level, and skin characteristics.

Air trapped between your skin and the liner creates problems including reduced suspension, uncomfortable movement during walking, and potential skin irritation. Similarly, wrinkles or folds in the liner create pressure points that can lead to skin breakdown. Taking the time to apply your liner carefully and consistently prevents these issues and contributes to all-day comfort.

Step-by-Step Liner Application

How Do You Put the Prosthetic Socket On?

To don the prosthetic socket, sit on a stable surface and hold the prosthesis with the socket opening facing upward. Guide your residual limb (with liner applied) into the socket, using a pull sock for suction systems or allowing the pin to engage for pin-lock systems. Ensure your limb is fully seated in the socket before engaging the suspension mechanism.

The socket donning process varies depending on your suspension system, and mastering your specific technique is essential for comfortable, secure prosthetic use. Most people learn their initial donning technique during rehabilitation, but refinement and practice over months and years lead to faster, more reliable results. Understanding the principles behind your system helps you troubleshoot problems and adapt to changes in your residual limb.

Suction and vacuum systems work by creating negative pressure inside the socket, essentially "sucking" the prosthesis onto your residual limb. This requires an airtight seal and full limb seating in the socket. Pin-lock systems use mechanical engagement between a pin on your liner and a locking mechanism in the socket. Hybrid systems combine elements of both approaches. Each has advantages and specific donning requirements.

The goal of socket donning, regardless of your suspension type, is to achieve full contact between your residual limb and the socket, secure attachment that won't release during activity, and comfortable weight distribution that allows all-day wear. Problems with any of these aspects can usually be traced to the donning process and corrected with technique adjustments.

Donning with Pin-Lock Suspension

Pin-lock systems are among the most common suspension methods for above-knee prostheses because they're reliable and relatively easy to don. The pin at the end of your liner inserts into a shuttle lock mechanism in the socket, clicking into place when fully engaged. This mechanical connection provides secure attachment for most activities.

To don with a pin-lock system, first ensure your liner is properly applied with the pin extending straight from the distal end. Sit on a stable chair or surface with your prosthesis positioned in front of you. Hold the socket with the opening facing up and align the pin with the pin receiver in the socket. Guide your residual limb into the socket while keeping the pin centered in the receiver channel.

Continue pushing down into the socket until you hear and feel the pin click into the lock. Most systems produce multiple clicks as the pin advances; continue until you hear the final engagement click. Pull gently upward on the prosthesis to confirm the pin is fully locked. If the prosthesis pulls away, reposition and try again, ensuring the pin is properly aligned with the receiver.

Donning with Suction Suspension

Suction systems create suspension through vacuum pressure between the liner and socket. This typically requires a pull sock or push-in method to expel air while seating your limb fully in the socket. Suction systems often provide excellent proprioception (sense of limb position) and a very secure attachment, but they require more careful donning technique.

For suction systems using a pull sock, apply the pull sock over your liner before beginning socket entry. Feed the sock through the valve hole at the bottom of the socket. As you push your limb into the socket, pull on the sock to help draw your limb fully into the socket while expelling air through the valve opening. Once fully seated, remove the pull sock and close the valve.

The seal for suction systems depends on the liner creating an airtight interface with the socket walls. Any gaps, wrinkles in the liner, or debris can compromise the seal and reduce suspension effectiveness. Check for proper seal by attempting to lift the prosthesis slightly; you should feel resistance from the suction. If the seal breaks easily, redon the prosthesis after checking liner placement and socket cleanliness.

Donning with Vacuum-Assisted Suspension

Vacuum-assisted suspension systems use an active pump mechanism to create and maintain negative pressure in the socket. These sophisticated systems provide superior volume management and very secure attachment, making them popular for active users. The pump may be mechanical (activated by walking) or electric (battery-powered).

Donning vacuum-assisted systems typically combines elements of suction donning with activation of the pump mechanism. After inserting your limb into the socket and establishing initial contact, activate the pump according to your specific system's instructions. You'll feel increased grip as the vacuum develops. Monitor the system's indicator (if equipped) to ensure adequate vacuum level is maintained.

How Do You Verify Proper Prosthesis Fit?

After donning your above-knee prosthesis, verify proper fit by standing using stable support, checking for even weight distribution, and taking several test steps to ensure the socket is fully seated and the knee mechanism functions smoothly. Your residual limb should feel secure without painful pressure points, and the prosthesis should move as a natural extension of your body without pistoning or slipping.

The verification step is crucial because even experienced prosthesis users occasionally don their device improperly. Small misalignments or incomplete seating that seem minor while sitting can become significant problems once you're walking and putting full weight on the prosthesis. Taking a minute to verify fit prevents falls, skin problems, and the frustration of having to redon mid-activity.

Verification involves both subjective assessment (how the prosthesis feels) and objective checks (what you observe). With experience, you'll develop an intuitive sense of when the prosthesis is seated correctly versus when something is off. However, systematic verification remains important, especially when you're learning or after changes to your prosthetic system.

Standing and Weight-Bearing Check

Using a stable support surface such as parallel bars, a sturdy chair, or a countertop, carefully stand while bearing weight on your prosthetic side. Note how the weight distributes across your residual limb. Properly fitted and donned prostheses distribute weight broadly across the limb surface rather than concentrating pressure in specific spots. If you feel a sharp pressure point, the prosthesis may not be fully seated or there may be a fold in the liner.

Stand with equal weight on both legs and assess your hip and pelvis position. With a well-fitted prosthesis that's donned correctly, your pelvis should be relatively level and you shouldn't need to lean significantly to one side. Asymmetry may indicate incomplete socket seating or alignment issues that need addressing.

Walking Verification

Take several steps in a safe area while maintaining access to support if needed. During these initial steps, focus on several aspects of prosthetic function. First, verify that the suspension is holding securely by noting whether the prosthesis stays attached during the swing phase of gait (when your prosthetic leg is in the air). Pistoning—vertical movement of the prosthesis relative to your residual limb—indicates suspension problems.

Assess the knee mechanism by noting whether it provides appropriate stability during stance phase and controlled movement during swing. For mechanical knees, you should feel confident that the knee won't buckle when you put weight on it. For microprocessor knees, allow the system to calibrate to your walking pattern over the first several steps.

Finally, verify overall comfort during walking. While some initial awareness of the prosthesis is normal, you shouldn't experience sharp pain, uncomfortable pressure, or instability. If problems persist, stop and assess whether redoning might help, or whether you need to contact your prosthetist.

What Should You Do If You Have Problems Donning Your Prosthesis?

Common prosthesis donning problems include difficulty achieving suction, incomplete socket seating, liner slippage, and discomfort during weight-bearing. Most issues can be resolved by checking liner application, ensuring clean and dry skin, adjusting sock ply, or using donning aids. Persistent problems that don't respond to troubleshooting should be addressed by your prosthetist, as they may indicate the need for socket adjustments.

Donning difficulties are common, especially in the first months after receiving a prosthesis, and during periods of residual limb volume change. Understanding the most common problems and their solutions empowers you to address issues independently when possible and to recognize when professional help is needed. Developing troubleshooting skills is an important part of becoming a confident prosthesis user.

Many donning problems stem from residual limb volume fluctuations, which are particularly pronounced in the first year or two after amputation but continue to some degree throughout life. Your limb volume can change from morning to evening, with activity, in response to weather or altitude, and with weight changes or fluid retention. Your prosthetist should have taught you strategies for managing these fluctuations.

Difficulty Achieving Suction

If you're having trouble achieving or maintaining suction, first check for the obvious culprits: moisture on your skin or liner, debris in the socket, or wrinkles in the liner that prevent an airtight seal. Even small amounts of perspiration can significantly reduce suction effectiveness. Thoroughly dry your skin and liner, and clean your socket if needed before trying again.

If the problem persists despite a clean, dry interface, the issue may be related to limb volume. If your limb has lost volume (common later in the day or after increased activity), you may not be achieving sufficient contact with the socket walls to create suction. Adding prosthetic socks over the liner can compensate for volume loss. Conversely, excessive volume (often in the morning or after periods of inactivity) can make socket entry difficult; in this case, elevating your limb briefly before donning may help.

Socket Won't Seat Fully

Incomplete socket seating is uncomfortable and compromises both suspension and weight distribution. If you can't get your limb fully into the socket, first check whether the liner is bunching or folding during insertion. Remove the prosthesis, reapply the liner if needed, and try again with careful attention to keeping the liner smooth during socket entry.

Excessive limb volume is a common cause of incomplete seating. If your limb feels swollen compared to normal, try elevation for 10-15 minutes before donning, or apply an elastic bandage briefly to reduce swelling. If volume excess is frequent, discuss long-term solutions with your prosthetist. Using a pull sock more aggressively can sometimes help achieve full seating by applying more draw to pull the limb into position.

Managing Sock Ply

Prosthetic socks are measured in "ply"—a unit indicating thickness. Your prosthetist should have advised you on appropriate sock use for your system. Socks serve primarily to compensate for limb volume changes, allowing consistent socket fit despite the normal daily fluctuations in your residual limb size.

How Do You Care for Your Prosthesis and Residual Limb Daily?

Daily prosthesis care includes cleaning your liner with appropriate cleaners after each use, inspecting components for wear or damage, wiping the socket interior, and maintaining your residual limb through proper hygiene and skin inspection. Consistent daily care extends component life, prevents skin problems, and ensures safe, reliable prosthetic function.

The daily care routine you establish for your prosthesis and residual limb directly impacts your comfort, skin health, and component longevity. While the routine may seem time-consuming at first, most people find that it becomes automatic with practice and takes only a few minutes. The investment in daily care pays dividends in fewer problems and more reliable prosthetic use.

Your prosthetic liner requires the most attention because it's in direct contact with your skin and accumulates perspiration, skin cells, and bacteria throughout the day. Most liners should be washed daily with mild soap and water or a specialized liner cleanser, then allowed to air dry completely before the next use. Having two liners and alternating them allows complete drying time and extends the life of each liner.

The socket interior should be wiped clean regularly to remove any debris, perspiration residue, or liner material that may have transferred. Use a damp cloth with mild soap, then wipe dry. Check the valve, pin lock, or other suspension components for proper function. Accumulated debris in these mechanisms can cause malfunction.

Residual Limb Care

Your residual limb requires consistent attention to maintain skin health and prevent the complications that can interrupt prosthetic use. After removing your prosthesis each day, wash your residual limb with mild soap and water, then dry thoroughly. This is also an ideal time for your evening skin inspection, looking for any changes from the morning or new areas of concern.

Apply moisturizer to your residual limb in the evening after removing the prosthesis, allowing it to absorb fully overnight. Keep your nails trimmed and avoid ingrown toenails on your sound foot. Maintain overall health through appropriate nutrition and hydration, as your body's ability to heal and adapt to prosthetic use depends on general wellness.

When Should You Contact Your Prosthetist or Healthcare Provider?

Contact your prosthetist if you experience persistent fit problems, skin breakdown that doesn't heal, unusual wear on components, changes in socket comfort, or if donning techniques that previously worked no longer achieve good results. Seek medical attention for signs of infection (increasing redness, warmth, discharge, fever), severe pain, or significant swelling that limits prosthetic use.

While many donning and fit issues can be resolved independently, recognizing when professional help is needed prevents minor problems from becoming serious. Prosthetists have specialized training and equipment to assess fit, make adjustments, and address issues that you can't manage on your own. Regular scheduled visits, typically every six months, allow monitoring even when no acute problems exist.

Skin problems represent one of the most common reasons for prosthetic consultations. Minor skin irritation that responds to rest and doesn't worsen can often be monitored at home. However, any open wound, blister that ruptures, or area that appears infected requires professional evaluation. Continuing to use a prosthesis over compromised skin typically worsens the problem and can lead to serious complications.

Changes in fit that develop gradually may indicate residual limb volume changes that require socket modification. If you find yourself adding progressively more sock ply or can no longer achieve the fit you're used to, your socket may need adjustment or replacement. Significant weight loss or gain, changes in activity level, or the natural maturation of a relatively new amputation site can all precipitate the need for socket changes.