What is a Prosthesis? | Prosthetic Specialists in Kansas City

What is a Prosthesis? | Prosthetic Specialists in Kansas City

A well-functioning prosthesis is becoming more and more important in today’s world. According to the Amputee Coalition, there are nearly 2 million people in the United States living with limb loss. But if you’re a new amputee patient, trying to understand exactly what a prosthesis is may end up being confusing and full of technical jargon. Although crutches and wheelchairs can help keep someone mobile on a temporary basis, prosthesis is a long-term solution that enables patients to get back to their daily lives without hindrance.

At Horizon Orthotic & Prosthetic Experience, we believe that learning about a prosthesis should be simple and straightforward, and we’ve been creating great-fitting prosthetic and orthotic devices since 2007. 

What is a prosthesis?

Simply speaking, a prosthesis is a medical device meant to replace a particular body part. Although some can be solely cosmetic, most prosthetic devices are designed to increase functionality and mobility. Patients needing a prosthesis or prosthetic device may have been born without a limb or had an amputation due to trauma or disease. Prostheses come in a variety of shapes and sizes, which are custom designed and built for each patient. 

Benefits of prosthesis 

Increased functionality: Prosthetic devices give patients the freedom to go about their daily tasks like walking the dog or cooking without the help of someone else. 

More energy: Using crutches, especially in places with a lot of stairs, can expel a lot of energy and make you tire quickly. A prosthesis takes away a lot of that extra work, making life a lot easier for you. 

A better outlook on life: Getting a prosthesis helps you get back to your everyday life. Patients tend to be happier and more positive when they can return to doing the things they love. 

Types of prosthesis

Depending on your specific needs, there are different types of prosthesis that can be customized and fitted to your body. They can either be permanent, like those placed inside the body, or they can be removable. The most common removable prostheses are arm prosthetics and leg prosthetics. 

Arm prosthesis 

Arm prosthetics solve problems associated with arm and hand functionality such as grabbing, reaching, and eating. It can also help with occupational demands such as typing and painting. 

Transradial prosthetics

A transradial prosthesis is designed to replace an arm that’s missing below the elbow, including the hand. When it comes to below-elbow prosthetics, there are two main types:

  1. Cable-operated: With cable-operated prosthetics, a harness and cable are attached around the opposite shoulder of the residual limb. 
  2. Myoelectric: Myoelectric prosthetics use electrodes to sense when the muscles in the upper arm move. This causes the artificial hand to open and close. 

Transhumeral prosthetics 

A transhumeral prosthesis replaces an arm that’s missing above the elbow. These are slightly more difficult to build and maneuver because of the complexities that stem from mimicking the elbow’s movements. 

Leg prosthetics 

Leg prosthetics increase the functionality of lower limbs. This includes the ability to walk, bike, and sit without additional assistance. 

Transtibial prosthetics 

Transtibial, or below-knee, prosthetics replace a leg from the knee down. Patients are usually able to regain full function fairly quickly, since retaining the knee allows for better movement. 

Transfemoral prosthetics:

Transfemoral, or above-knee, prosthetics replace a leg starting above the knee. Similar to above-elbow prosthetics, movement is trickier because of the way the knee moves. In more complex prosthetics that implement advanced technologies such as computer microprocessors, a patient is able to have more control than with basic prosthetics. 

Parts of a prosthesis

Prostheses come in a variety of designs and functions, but most removable prostheses have the same basic parts:

  1. Socket
  2. Interface
  3. Structural Components
  4. Suspension System 
  5. Cover & Cosmetics

Socket

The prosthetic socket is the portion that is custom built to fit the shape and size of the residual limb. A highly skilled prosthetist designs and builds the socket to maximize the amputee’s comfort, control, and proprioception in the prosthesis. The socket is the most important component of the prosthetic device because if it does not fit, the patient will likely not wear the prosthesis.

Customized sockets are a crucial part of a prosthetic since they connect the limb to the rest of the device. Sockets also come in different forms:

  • Patella Tendon Bearing (PTB) Sockets: PTB sockets were developed in the early 1900’s. They often utilize a foam liner for padding. In this socket design, pressure is focused on areas that tolerate pressure with relief areas in the socket for more sensitive spots.
  • Total Surface Bearing Sockets (TSB): TSB sockets emerged as the development of gel liners came into the industry. With gel liners, generally all areas of the residual limb can tolerate pressure. This improves comfort, control, and proprioception for the amputee and has reduced the number of sores that were associated with PTB sockets.
  • Double Wall Sockets: Double wall sockets are basically two sockets in one. They consist of a shorter inner socket and an outer socket. This socket design can be utilized for any amputation level. 
  • Quadrilateral Sockets: Quadrilateral sockets are for the transfemoral, or above-knee, prosthetics.  These were developed in the mid 1900’s and were the first to utilize the ischial tuberosity as a primary weight bearing surface. This ischial weight bearing socket design is still used today, though its use has significantly declined with the development of Ischial Containment Sockets
  • Ischial Containment Sockets: This socket design is also for above-knee prosthetics. These were developed in the late 1970’s and were the first to incorporate the ischial tuberosity inside of the prosthesis. This socket design is widely used today, but the trend is now towards Sub- Ischial Sockets.
  • Sub-ischial Sockets: Sub-ischial sockets meant for above-knee prosthetics and are the emerging trend in the prosthetic industry. Sub-ischial sockets are a low-profile socket where the socket comes up to the ischial tuberosity but does not come in contact with or contain the tuberosity.  
  • Not all socket designs work for all amputees. Your prosthetist at Horizon Orthotic & Prosthetic Experience will be able to evaluate you and recommend the most appropriate design to maximize your outcomes!

Interface 

The interface is the barrier between your residual limb and the prosthetic device. This barrier is worn over the residual limb to decrease the amount of friction, swelling, and skin damage. 

Gel cushion: A gel cushion is used for skin protection and helps to evenly distribute pressure throughout the limb. We advise that gel cushions be replaced every 12 to 24 months depending on how active you are. 

Prosthetic sock: Prosthetic socks are made of either wool, nylon, or other synthetic materials and can be as thick or thin as you may need. They are designed to manage any volume changes that could occur due to muscle atrophy, weather, and everyday activities. 

Structural Components

Structural components are individual pieces that come together to make a prosthesis. The prosthesis consists of a socket, pylon, foot, (knee joint for the above-knee prosthetics),  and connectors to attach the foot and knee components to the socket. Various materials can be used for these structural components, including titanium, aluminum, stainless steel, or carbon composites.

Suspension System

The suspension system is meant to keep your prosthesis securely attached to your limb. There are a variety of different ways this can be done based on your unique prosthetic needs. 

  • Direct suction sockets: Direct suction sockets are usually exclusive to above-knee patients. These are flexible sockets that don’t require a liner. 
  • Suction: A suction suspension system works by forcing air out of a one-way expulsion valve when the limb is put inside the socket. The resulting suction effect keeps the prosthesis secure. 
  • Elevated vacuum sockets: Elevated vacuum sockets use a system that includes a liner, suspension sleeve, and a pump to remove air. 
  • Locking pin: The locking pin suspension system uses a cushion interface along with a pin to keep the prosthesis in place. To remove the device, there’s a release button to disengage the locking pin.
  • Belts and straps: If all else fails and the other methods aren’t comfortable, belts and straps can be used to attach the prosthesis. 

 

Read more on suspension methods for below-knee patients. 

 

Cover & Cosmetics

In addition to the prosthesis itself, some patients prefer to add additional cosmetic features to make them look more natural. This is done by shaping and applying a foam material to their prosthesis that feels similar to muscle tissue. Patients can then have synthetic skin applied to match their skin tone. All of this is completely optional; some people, especially athletes, prefer the untouched prosthetic skeleton.  

At HOPE KC, patients can also create a unique cover to reflect their own personality.  These covers can make the prosthesis look high tech or futuristic. By involving our patients in the design of their own cover, we have found that they wear the prosthesis proudly and are eager to show off their work!

How a prosthesis is made

Before anything can be made, you’ll want to meet with your prosthetist so that he or she can understand your goals and other needs. If you’re looking for a new custom prosthesis in Kansas City, you can schedule a free consultation online with HOPE KC. 

The process to create a custom prosthetic device can take several weeks and requires a strong attention to detail. Often times, a patient will be invited to come in for multiple consultations and fittings to ensure that the prosthesis is as comfortable and functional as possible. There may be some variances, but for the most part, the following step-by-step process we use at HOPE KC is fairly standard in the prosthesis industry. 

Step One: Preliminary evaluation and measurements

Once you’re ready to move forward with your prosthesis, we will start by evaluating your goals and desires. This allows us to design a prosthesis that will maximize your functional outcomes.  We then take a series of measurements of your residual limb and sound side limb. This helps to create a prosthesis that will be the best fit for you. 

Step Two: Casting the limb

In order to build an accurate, customized device, your limb will either have to be hand cast with plaster or scanned by a 3D scan. Doing so ensures that your prosthetic device will match your body perfectly to maximize comfort. 

Step Three: Creating a diagnostic socket 

Usually, we first create a clear test socket to see how it will work with your prosthesis. This allows your Kansas City prosthetist to see pressure spots and how it interacts with your limb. If it doesn’t work, we will make a second to ensure that you’re comfortable and your prosthetic device fits as best as it can. 

Step Four: Delivery and final fitting

Once all these steps are complete, we will deliver your prosthesis ready to wear. This process may take longer if you are new to using a prosthesis or have just finished surgery. 

At HOPE KC, our work isn’t finished once your prosthesis is done. We dedicate much of our time with our patients to helping them adjust and teaching them the best ways to care for their device.

How to take care of a prosthesis

Once you have your prosthesis, you’ll want to take proper care of the device in order to reap the full benefits. The last thing you’d want is to do is neglect your prosthesis and find that it won’t last as long as you expected. Here are a few tips to keep in mind:

  • Remove the prosthesis before bed and examine your residual limb for any redness or irritation. 
  • Wash your prosthesis daily with water and mild soap to avoid dirt and bacteria buildup. This includes washing the part of the socket that touches your skin.
  • To avoid water damage, never fully immerse your prosthesis in water unless you’ve gotten one that is waterproof. 
  • Avoid using chemicals that could damage or alter the materials of your prosthetic device. 
  • Use your prosthesis only for your normal activities. Most are not made for high-impact activities, and doing so could damage your device. If you need a more specialized prosthesis, talk to your HOPE KC prosthetist about how we can help you optimize a prosthesis for athletics or other highly physical activities. 

How to get a prosthesis in Kansas City

If you’re looking to get a prosthesis in Kansas City, Horizon Orthotic & Prosthetic Experience has six different locations in the Kansas City metro area and other Missouri cities to help you achieve your goals. Our customized prosthetics are made with the patient’s specific needs in mind. 

We give our patients HOPE by providing them with the tools to have their dream lifestyle.

Contact us for more information on how to get a prosthesis in Kansas City.