Although there are a variety of prosthetic suspension systems in Kansas City, the main goal for all are clear—maximizing comfort while promoting mobility. When a suspension system works well to connect your residual limb to your prosthesis, there’s a balance that allows you to maneuver through daily life. However, when suspension is off, it can cause discomfort and even pain.
As prosthetic experts, our providers at Horizon Orthotic & Prosthetic Experience recognize the value in choosing a suspension system that works best for our patients’ needs. The key in doing so is through education and ensuring our patients are aware of which options are available.
Read on to gain more insight on different types of prosthetic suspension systems and why they are important.
What are prosthetic suspension systems?
Simply speaking, a prosthetic suspension system keeps the residual limb connected to the prosthesis. This connection is crucial to the overall prosthetic design, and the better that connection is, the greater the comfort, control, and proprioception will be. The goal is to create the feeling that the device is more of an extension to your body rather than a hard-to-use hindrance.
Different systems control different forces that act against the residual limb. These forces include:
Rotation: When you put weight on your foot, your limb may rotate inside the prosthesis, which isn’t ideal. The right suspension method will limit that amount of rotation to reduce excess movement that could cause irritation.
Shear: Shear forces push unaligned forces in the opposite direction. For your limb, that means your skin pulls as your limb moves back and forth inside your device when walking. This is also called pistoning.
Along with those forces, you also should consider proprioception. Proprioception is your body’s ability to sense itself, including its parts, how they’re moving, and location. This process involves sensory nerves in the muscle sending signals to the brain.
For amputees, however, they have to depend on their suspension connection to create that awareness. As you may suspect, a poor suspension system will lead to poor proprioception, which can negatively affect mobility.
Choosing the right suspension method considers:
- Length of the residual limb
- Limb volume fluctuations
- Joint stability
- Activity level
- Cosmetic requirements
- Sensation in the limb
- Vascular supply
Your prosthetist can help you determine which suspension will benefit you most, but oftentimes finding one that works for you will take a bit of trial and error. That is why it is very important to remain patient as you go through the fitting process. Remember, the goal is to get you up and going again, and the only way to do so is by ensuring that your suspension works for your lifestyle.
Benefits of a well-fitting suspension system
Increased functionality: When your suspension system properly keeps your limb and prosthetic device secure, you increase your mobility. This allows you to return to your daily tasks such as cleaning and walking your dog without assistance.
More energy: Overtime, you may notice you have more energy. The suspension system is designed to make your life easier. Especially if you’re used to crutches or maneuvering on a wheelchair alone, having a prosthetic device can take away that extra work.
A better outlook on life: Getting a prosthesis with the right suspension system helps you get back to your everyday life. Most people tend to be happier and more positive when they can return to doing the things they love.
Types of prosthetic suspension systems
Not every person will benefit from the same suspension method. For example, someone who plans to be more active won’t benefit from a system a less active person may use. There are four common suspension systems you may find in the Kansas City area and beyond:
- Self-suspending (supracondylar) suspension
- Elevated Vacuum
- Locking Pin
- Sealing Liners
- Belt and Straps
A suction suspension system implements a soft liner in conjunction with a one-way expulsion valve and suspension sleeve. The liner goes over the residual limb before placing it into the socket. As you apply weight, the valve releases air to keep your limb firm inside the prosthetic. Suction allows for even distribution of pressure to reduce friction and shear.
The sleeves are made of different materials, including:
- And more
In addition, suspension sleeves also prevent air infiltration and relieves excess perspiration. If there are changes in volume, you can easily manage this by adding or taking off sock plies.
A self-suspended system depends on the socket to secure the prosthetic device to your limb. These sockets are designed with a brim that firmly attaches to the residual limb. The brim extends and narrows and narrows over a joint to grab hold of the area, therefore creating a snug and secure effect.
For example, the bone in your upper arm (the humerus) has round knob-like bumps that protrude from the bone. A self-suspended socket will then extend past those knobby structures and tighten around the joint. As a result, the socket won’t come off easily whenever you move.
An elevated vacuum system is a bit more complex than a suction system, but they are still user friendly. This system involves three components:
- A cushion liner to maximize comfort
- A suspension sleeve (similar to the suction method) that creates a seal between the residual limb and the prosthesis
- A pump to remove excess air
Pumps come in two different types: mechanical or electrical.
Electrical pumps: Electrical pumps maintain a desired socket pressure range. When the socket goes below a certain threshold, the pump activates to release air. This allows you to start walking right away, even if you’ve been sitting for a prolonged period. Keep in mind that you must charge your electrical pumps each night for them to work properly.
Mechanical pumps: Mechanical pumps compress air with each step. Unlike electrical pumps, you may have to take a few steps before it loosens, but you won’t have to charge them.
The locking pin suspension system uses a liner/cushion interface along with a pin to keep the prosthesis in place. The liner rolls directly onto the limb to create a base. For suspension, the pin is threaded through the far end of the liner/cushion. In this method, the liner/cushion also acts as a socket interface to protect your residual limb. You would also wear a prosthetic sock to balance volume fluctuations. To remove the device, there’s a release button to disengage the locking pin.
The sealing liner suspension system uses a liner with a gasket ring around the outer portion of the liner. This ring gets lubricated with a standard hand sanitizer or alcohol spray to allow it to slide into the socket. A one-way expulsion valve allows air to evacuate but not come back in. This creates suction suspension without the need of an extra suspension sleeve /cushion interface along with a pin to keep the prosthesis in place.
Belts and Straps
With the new technology available in the prosthetic industry, belts and straps have become a more old-fashioned method for suspension. This fairly inexpensive suspension system uses belts, straps, and cuffs to hold the prosthesis in place. Though not used as often, belts and straps can be a great alternative if the previous methods don’t work. They are also used for people who have a short residual limb or need an auxiliary suspension while going through rough terrain.
Problems with an improper suspension system
If you have a suspension system that doesn’t work for your body, you may notice side effects that takeaway your ability to walk. For many, this could lead them to stop wearing their prosthetic device, which could lead to frustration. Here are a few signs that your suspension method may need to be assessed or changed.
Your skin has become irritated.
A prosthetic suspension system is supposed to reduce skin irritation and help the socket do its job. If you’re finding that your skin is red, blistered, or ulcers are forming, you should return to your prosthetist. That way he or she can examine your prosthetic device and reevaluate other methods.
You are having balance issues.
For lower-limb amputees, balance between your healthy limb and the prosthesis is key for optimal mobility. If you are having trouble balancing, it usually means there’s an alignment issue that’s affecting proprioception. As time passes, your residual limb will go through changes, and you’ll need to get a new socket and or change the suspension method to maintain control over your prosthetic device.
You are suffering with back pain.
Walking with a prosthesis that isn’t properly suspended can cause long-term structural changes to your spine due to improper gait patterns. As a result, you may notice low back pain and it could even lead to further spinal injuries if you don’t resolve the issue.
Your residual limb doesn’t fit properly into the socket.
In order for the suspension system to work, your residual limb must fit. There is no way around that fact. Since prosthetists perform in-depth fittings, this problem usually arises after months or years of use. Sometimes weight changes or swelling can change how your prosthesis fits, therefore affecting its suspension system.
For swelling, first make sure you’re wearing your shrinker sock every night to see if the problem resolves itself. If swelling is not the cause, you should talk to your provider. The solution could be as simple as getting a new socket or you may have to switch out your suspension. At times, both in conjunction may be the best option.
Learn more about prosthetic suspension systems in Kansas City with Hope KC
If you’re looking for more information about prosthetic systems, our team at Horizon Orthotic & Prosthetic Experience can offer you the expertise you need. We have six different locations in the Kansas City metro area and other Missouri cities to help you achieve your goals. Plus, we create customized prosthetics that are made with the patient’s specific needs in mind.
At the end of the day, we give our patients HOPE by providing them with the tools to have their dream lifestyle.
Contact us for more information or if you’re seeking a prosthetic device for you or a loved one.