Getting the Most Out of Your Prosthesis

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Volume 17 · Issue 4 · July/August 2007 | Download PDF

by Jason T. Kahle, CPO, and M. Jason Highsmith, DPT, CP

Getting The Most Prosthesis 01

A wide variety of prosthetic components are available today, but you should discuss the pros and cons with your prosthetist in regard to what your insurance plan will cover.

When it comes to saving money, insurance companies are pretty smart – geniuses, in fact. From our perspective, it seems that prosthetic services are under attack by insurance companies. The Amputee Coalition is doing great work to protect access for prosthetic coverage. However, many companies still have ridiculously low limits on prosthetic coverage. Also very common are high co-pays that increase proportionately as the cost of a device increases. Like a car, the more bells and whistles your prosthesis has, the more expensive it becomes. Generally speaking, the higher the price of the component, the higher the quality. Unfortunately, when it comes to paying for the prosthesis, the insurance company is ultimately “the boss.”

Some facilities have an employee dedicated to convincing patients’ insurance companies what their patients’ needs are. Sometimes, however, an insurance company will compromise on the type of prosthesis a facility would like to fit on its patients. When this happens to you, it’s important that your prosthetist communicate this with you, so you can jointly decide where you need to compromise to get the maximum benefit of your prosthesis.

The Billing Process

If you examine your Explanation of Benefits (EOB) closely, it will show you a detailed report of what your prosthetist will bill for. This will consist of anywhere from one to 20 (or more) billing codes. Your prosthetic facility will usually only bill what is absolutely necessary in this process; some codes can be dropped without too much compromise to the prosthesis. You should always check this process closely and fully understand what you’re paying for. Discuss this with your prosthetist to ensure he or she is appropriately billing for what you need and actually receive.

The Fitting Process

New amputees will receive a preparatory prosthesis (sometimes called a temporary prosthesis). Several months later, this will be replaced by the definitive prosthesis. There are three main reasons for this process. Amputees’ residual limbs will lose their postoperative edema (swelling) and significantly shrink over the first two to six months. The preparatory prosthesis will take them through this stage. This becomes ill-fitting after several months and will need to be replaced. The insurance company knows this and will only allow basic components at this stage.

Sometimes, if we know that the insurance payment is an issue, what we will do is bill for the definitive prosthesis right away, for the first fitting. When the patient inevitably loses volume, we will replace the interface only. By billing it this way, the insurance company will not scrutinize (as closely) the cost of components because we’re not billing it as a preparatory prosthesis; instead, we’re billing it as a definitive prosthesis. We can fit higher-end components at an earlier stage. We also have the option to fabricate a foam cover when we fit a prosthesis in this manner (insurance companies won’t pay for a foam cover when fitting a preparatory prosthesis). Fitting a prosthesis this way can save 15 to 30 percent of the total cost of the first two fittings.

The downside? You won’t have a spare prosthesis. The preparatory interface (socket) is routinely replaced when fitting the definitive. This can be done at little or no cost because we’ve already gone through the process of fitting the definitive and have a model that can be used for the “extra” (spare) interface. This extra interface can be attached to the preparatory components. This becomes the patient’s “spare.” If there’s no preparatory prosthesis, this obviously can’t be done. The other downside is that the prosthetist has to make an educated, experienced guess on what components you will benefit most from over the life of the definitive prosthesis.


Evidence Based Care 02

When a patient loses volume, a thicker flexible interface could be substituted for a thinner flexible interface to help avoid a total interface replacement. Graphics courtesy of Otto Bock HealthCare

The interface is always the most important part of a prosthesis no matter what level of amputee you are. However, there are several shortcuts that can be made in this area. If your prosthetist uses or suggests a flexible interface, this is an additional charge. We sometimes use a thicker liner or more socks in the fitting and eliminate the flexible interface. The downside here is that you don’t have the versatility of interface adjustments, nor can the inner interface simply be shrunk (or reduced) when there is gross volume fluctuation. Another interface strategy is to limit the number of evaluation interfaces (check sockets). Most prosthetists will only fit one or two in the fitting process. Each time the prosthetist fits one, it’s an additional charge.


Getting The Most Prosthesis 02

An energy-storing foot (left), combined with an ankle unit (right), can provide multiaxial (ankle) function and energy return similar to a more expensive foot. Graphics courtesy of Endolite.

There are literally hundreds of feet on the market. Factors to consider include: durability, weight, function, energy return, flexibility, shock pylons, torsion adapters and maintenance. Usually, the higher the cost, the more these features will be rolled up into one foot. For example, a carbon fiber foot provides a great spring for energy return and is ultralightweight. But sometimes adding one feature will detract from another. A shock pylon will give you a shock absorber, and sometimes torsion, but it’s heavy and will require periodic maintenance. So the key is to consider which features of a foot are absolutely necessary. This helps you narrow your choices and make the best decision as to which foot will benefit you the most.


In terms of cost, there are three basic categories of knees: friction-controlled, fluid-controlled and microprocessor-controlled. Friction-controlled knees are ideal for one-speed walkers, such as those whose walking is mostly confined to their house and who have no need to be able to change their speed. We only fit this knee when the above criteria are strictly met because we believe that most amputees have the ability to achieve some amount of variable cadence and that all amputees should be able to respond quickly in a “fight or flight” situation if needed.

Fluid-controlled knees come in all shapes and sizes. The fluid aspect of the knee typically controls the swing phase of walking (when the prosthesis is in the air). If you walk at more than one speed or if you feel that your leg isn’t “keeping up with you,” you should probably use a fluid-controlled knee. There are fluid knees that have extension assists, braking mechanisms, stance flexion features, locking features, dual modes or other functional features. These features usually mean more billing codes. It’s important to understand what these features do and to discuss with your prosthetist whether you would get any benefit from them. For example, stance flexion has been a historically popular feature incorporated in both older and newer knees. However, according to the prosthetic literature (and our clinical experience), few patients actually use it. Many people tend to choose knees that don’t have stance flexion if cost is a concern.

Getting The Most Prosthesis 04

Cosmetic covers provide a realistic appearance, but they’re expensive, they add weight, and they make adjustments more difficult. A custom lamination, using store-bought fabric, is a lighter, economical alternative. Graphics courtesy of Otto Bock HealthCare.

Microprocessor-controlled knees can control swing and stance or swing only. The knee “thinks” for you and has proven to be an excellent choice for patients of diverse functional abilities. But microprocessor knees are very expensive. In our region, Medicare has recognized a need for our patients, but many private insurance companies exclude microprocessor knees. In such a case, if you and your prosthetist agree that a microprocessor knee is the best choice, the next step is to convince your insurance company that it is the best choice. This often requires that your physician write a letter and provide progress notes that you can, do and will continue to benefit from a microprocessor knee. Some facilities assist this process by having loaner microprocessor knee units available for candidate patients to try out. By allowing a trial period with a microprocessor knee, prosthetists can get a much stronger idea of whether someone will benefit from using it. It also adds to the evidence that they can present to the insurance company that the knee truly is a medical necessity.

While there are several strategies to reduce the overall cost of a prosthesis, it is ultimately important not to compromise function and comfort. There are several good reasons why prosthetists will suggest the interface, foot and knee that they do, including experience, knowledge, familiarity with component choices, and an understanding of you and your needs. If reducing the price means compromising quality, you should bear the following advice in mind:

Always make sure that your needs are being met by your prosthetist and your insurance company. You pay for your insurance; therefore, you have a voice. It is important to take control of your situation and get exactly what you need. If your insurance company isn’t providing you with appropriate care, you always have the choice to research and switch to one that does.

About the Authors

Getting The Most Prosthesis 05Jason T. Kahle is a certified and licensed prosthetist/orthotist. He is the director of lower-extremity prosthetics at Westcoast Brace & Limb in Tampa, Florida

Getting The Most Prosthesis 06M. Jason Highsmith is a physical therapist and certified prosthetist. He is an assistant professor in the School of Physical Therapy & Rehabilitation Sciences at the University of South Florida.