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What to consider when it's time for a new prosthetic knee

When the music starts, Rob Rieckenberg is the first one on the dance floor. Don Davis can often be found on the tennis court, on horseback or on water skis. When Leslie Pitt Schneider heads to the airport for yet another overseas trip, she feels confident leaving her crutches at home.

No matter what you rely on your prosthetic knee to help you do, there’s no doubt your knee is an integral part of your life. When it comes time to replace it, you owe it to yourself to consider your options thoughtfully.

More prosthetic options are available than ever before. Rob, Don and Leslie all agree that amputees should keep up to date about new prosthetic products and technologies. “There have been more advancements in prosthetics in the last four years than in the last 40 because of soldiers coming back from combat with limb loss,” said Rob, a 35-year-old insurance specialist who has worn an above-the-knee prosthesis for eight years.

Don, an active volunteer and patient advocate, wears an above-the-knee prosthesis on one side, and below-the-knee prosthesis on the other. He encourages people to be open with their prosthetist about their needs. “Your prosthetist doesn’t know how the leg feels to you, how it’s functioning for you,” he said. “You’re the person who is wearing it. You have to be honest and tell them what’s going on and what you want.”

If you don’t have a prosthetist you are comfortable with, it pays to find one, says Cale Konetchy, C.P., a clinical specialist in prosthetics for Ottobock. “Think of the relationship with your prosthetist as a long-term investment in your prosthetic care,” he said.

See “How to Choose and Work With a Prosthetist" for more information.

Six topics to discuss with your prosthetist

1. Changes in your physical status

Let your prosthetist know about such issues as development of skin irritation, change in volume of your residual limb, weight gain or loss, and increased stumbling or falling.

2. Your current and desired activities

“What do you want to do that you can’t do now?” and “How does your current prosthesis limit your activities?” are good questions to start with, Cale said.

Your answer to that question may be “nothing” or “not at all.” That’s the case with Leslie, clinical and regulatory affairs manager for Ottobock. Her activity level has not changed since first getting her C-Leg Microprocessor Prosthetic Knee, so she is planning to stick with that product at her next replacement.

But many times over the almost 40 years Leslie has worn a prosthetic leg, she has experienced the impact that new technology can make. When she went from a hydraulic knee into the C-Leg eight years ago, it changed her life. “Almost right away, walking was amazing and effortless,” she said. “For the first time, I could walk down steps foot over foot.

“Even if you stick with the same technology, it will be an adjustment, because every prosthetic system is custom,” she continued. Also, the product you’re using may have undergone an upgrade that could be an improvement for you. It’s worth talking to your prosthetist about this.

At 66 years of age, Don, who has the C-Leg, is considering how much longer he wants to continue to play tennis. “That’s the sport that beats up the leg the most,” he said. He would like to be able to go up stairs step over step, so he is looking at the Genium Bionic Prosthetic System.

Rob got the Genium above-knee prosthesis last year. “Now I can walk up and down hills step-over-step, even at an angle,” he said. “It’s great for getting on and off planes. And I can tackle the big hill in my yard with the lawn mower.”

In addition to looking at what the leg would enable you to do, it’s important to consider the limitations imposed by the knee you are considering, Cale said. There may be limitations to how the knee performs on stairs, hills, uneven terrain and ramps, for example.

3. Functional limitations of the device

Ask your prosthetist about how the knee may be impacted by water, dust and dirt, cold, vibration and electrical and magnetic disturbances. If you are considering a microprocessor knee, ask about water exposure, warranty, service options in case a repair is needed, and how the knee operates when the battery is depleted.

It may be wise to consider having different knees for different activities. For example, Rob has a hydraulic knee he uses for hunting trips. “It’s completely waterproof, and I don’t have to think about recharging a battery,” he said.

4. Appearance of the prosthesis

If appearance is a concern to you, find out whether a cosmetic cover can be applied to the model you’re considering. “I am a woman working in a professional setting. I would not show up at work without a cover on my leg,” Leslie said.

Foam covers are very flexible. “Foam has a good memory, and it doesn’t break down,” she said. “Mine has a nylon cover that is milled in Italy, like Italian hosiery. It doesn’t run easily.”

5. Real-life performance

Consider asking your prosthetist for names of people they work with who have the product you are considering so you can talk with them in person. “Although privacy laws limit distribution of specific patient information, most reputable clinics will have established relationships with amputees who would be willing to meet with you to provide a realistic, first-hand account of what to expect, ” Cale said.

In addition, manufacturers such as Ottobock have patients who help train others and are available to speak with people considering their products, Leslie said.

But there’s nothing like a test drive to help you know for sure if something is for you. “If you have an opportunity to do a trial fitting with a specific product, do it, especially if you are going to a new technology,” Leslie said. Ottobock allows patients to try their products in the prosthetist’s office.

6. Financial considerations

Wide variation exists among insurance plans regarding coverage of prosthetic devices, Cale said. However, in general, insurance companies will consider coverage for a new prosthetic knee if:

  • the patient’s ambulation status has changed;
  • an essential component of the prosthesis has failed; or
  • the prosthetic limb has simply reached the limits of its ability to perform due to normal wear and tear.

“The typical lifespan of a prosthetic component is three to five years,” he said. “I’ve seen knees last 15 years, and I’ve seen them last two years. It depends on how active the person is and the environment where the prosthetic is most often used.”

How do you know if your knee needs replacing? See your prosthetist regularly and discuss with him or her any of the following signs of wear:

  • “play” in the knee – irregular side-to-side motion that gets worse over time;
  • clicking;
  • unnatural function in the knee that wasn’t present when the knee was delivered;
  • loss of hydraulic resistance -- a feeling like the knee will not keep up with you when walking fast, or the knee comes in front of you too quickly when walking slowly;
  • locking up.

If you begin tripping or falling repeatedly and that had not been the case before, see your prosthetist immediately.

Whatever your reason for needing a new prosthetic knee, be prepared for the fact that you may need to be persistent to get insurance coverage. One of the most important things you can do is to enlist your prosthetist’s help in educating your physician about what to include in their documentation, which is the basis for any coverage decision.

“A primary care doctor may have only one patient with limb loss in a population of 2,000 patients, so we can’t assume they know what documentation the insurance companies need,” Leslie said.

Don’t let fear of denial keep you from asking for what you need. “In my experience, if you have all the necessary documentation and all the details are taken care of, it dramatically increases the likelihood you will get reimbursement,” Cale said. “Every patient deserves the opportunity to investigate the full range of what’s available based on their functional abilities.”

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