From an old conventional above-knee prosthesis to a hydraulic knee: how do you adapt? A customer story
With an above-knee prosthesis, the socket and the knee component shape how you walk. Our customer, who had used a very old conventional prosthesis, had the alignment reset, chose a hydraulic knee, and then wore a check socket (a temporary trial socket) in daily life while details were fine-tuned before receiving the final prosthesis. How quickly people adapt, and the results, vary from person to person.
What was our customer's situation?
Our customer had an above-knee amputation and had worn prostheses for a long time. The one brought to us was a conventional prosthesis used for a great many years — one of the oldest we had seen.
We cannot say for certain why, but on examination the hip and thigh were angled noticeably outwards. That meant even the casting stage was likely to be challenging.
What makes up an above-knee prosthesis?
| Part | Role |
|---|---|
| Socket | Surrounds the thigh residual limb, carries body weight and connects the prosthesis to the body |
| Knee component | Holds steady when you stand, bends and straightens as you walk |
| Pylon | Connects knee and foot and sets the leg length |
| Prosthetic foot | Meets the ground, takes the weight and carries you into the next step |
How was the knee chosen?
While casting we corrected the alignment before anything else, then took plenty of time with our customer to compare several knee components. Weighing function against cost, our customer chose a hydraulic knee (for example, Total Knee 2000). It has a locking feature that stops the knee buckling when the leg is straight, and is designed to let the knee bend fairly naturally while walking.
Above-knee prosthetic knees fall broadly into the types below. These are general characteristics, and products within each type differ.
| Type | How it works | Things to consider |
|---|---|---|
| Locking knee | Keeps the knee straight and locked while walking | Very stable, but walking can feel stiff |
| Mechanical knee | Controls bending speed through friction or similar | Relatively simple construction |
| Hydraulic knee | Uses hydraulics to control bending and straightening speed | Tends to move smoothly as walking speed changes |
| Microprocessor (electronically controlled) knee | Sensors read your gait and adjust resistance | Needs charging and upkeep; higher cost |
How did the check socket help with adapting?
Because of the leg's shape there was a lot to watch for from casting onwards, but things went more smoothly than expected and we were able to make the intermediate check socket. Our customer said it fitted the residual limb well and felt comfortable.
Walking was the hard part. After so many years with a conventional prosthesis, a hydraulic knee that works differently meant learning again from standing. Walking was a real struggle to begin with, but after generous practice time in our clinic our customer soon got the hang of it. We also went through what to watch for when walking and how to sit down correctly.
- Practice in the clinic — learning to stand, walk and sit.
- Check socket in daily life — going home and living with it for a while to find any discomfort.
- Return visit and adjustment — fine-tuning leg length (height) and pressure around the thigh.
- Back to daily life — living with the adjusted check socket for a while longer.
- Final prosthesis — made from the check socket once walking had been fully tested.
When we met again, our customer described it as comfortable, had settled into the new prosthesis well, and was walking noticeably better. On receiving the final prosthesis, our customer thanked us warmly and asked us to keep looking after it in the years ahead. The time it takes to adapt, and the results, vary from person to person.
What to check before a new above-knee prosthesis
- Alignment of your current prosthesis and your posture — the older the prosthesis, the more a check matters.
- Type of knee — consider activity level, stability, upkeep and cost together.
- A plan for adapting — whether there is time to test a check socket in daily life.
- Aftercare — whether adjustments and after-sales care are available while you use it.
If you have back or hip pain, or skin problems, please speak to your doctor as well. Cost depends on the knee and foot components and the socket type; Korean residents can check public funding with the relevant agencies, and overseas customers receive guidance in consultation. At Silobionic we provide after-sales care while you use your prosthesis, and if a repair is not possible we will talk you through a remake.
Frequently asked questions
If I switch from a conventional prosthesis to a hydraulic knee, can I walk straight away?
Because it works differently, you may need to relearn from standing. This customer adapted through practice in the clinic and wearing a check socket in daily life; the time needed varies from person to person.
Why is there a check socket stage?
Before the final prosthesis is made, walking in a temporary socket in daily life lets details such as leg length and pressure be fine-tuned. The tested check socket then becomes the basis for the final prosthesis.
How do I choose an above-knee prosthetic knee?
We look at activity level, stability, upkeep and cost together, compare several types, and decide with you in consultation.
Can a prosthesis be made if my leg is angled or misaligned?
For this customer, we set the alignment before casting and were able to make the prosthesis. Every case is different, so we advise after seeing you in person; please discuss bone or joint issues with your doctor.
