Wheelchair Fit for Function and Support

July 11, 2020
Wheelchair Fit for Function and Support

People who use wheelchairs know the correct wheelchair fit is essential for comfort and optimal function. If a wheelchair doesn't fit correctly it not only causes discomfort but ultimately, if you sit in the wrong wheelchair long enough, it will damage your body.  Over time, inadequate posture support results in:

  • Pressure points that result in skin breakdown and wounds
  • Shortening of postural muscles and ligaments that result in misalignment of your joints
  • Damage to your shoulders and hands

"Your wheelchair is an important part of your life, so you want to make sure you end up with the right wheelchair that fits your body, preferences, activities and lifestyle" says The Model Systems Knowledge Translation Center (MSKTC), an advocacy group for individuals with traumatic brain injury (TBI), spinal cord injury (SCI), and burn injury. "With new types of wheelchairs and components coming on the market all the time, the days of "one size fits all" are long gone."  

Wheelchair Fit:  The Process

Wheelchairs are costly and can run upwards of thousands of dollars.  So, like any investment, it is worth taking time to ensure the chair you select will meet your current and future needs.  Health insurance will pay for a wheelchair if you meet the criteria they set.  But typically insurance will only replace a wheelchair every five years.  So anticipating any future changes in your function or how you will use the chair is important to consider.  

The wheelchair fit process entails three steps.  You will need to meet with and get reports from:

  • Your physician who documents in your medical record that you need a wheelchair
  • An occupational or physical therapist who writes a detailed report that specifies why you need the features of the wheelchair you have selected
  • The wheelchair supplier or durable medical equipment dealer (DME) who documents that the wheelchair you chose fits through the doorways of your house and you can operate it independently in your home

Wheelchair Fit:  The Team

Since buy a wheelchair is an investment that you want to work for at least five years, you want to get it right!  To make sure you get the best wheelchair for your needs, you want to start with the right team.  Your team should include experienced rehabilitation professionals who have a track record of success in getting wheelchairs approved for their clients.  Look for physicians, therapists and DMEs who:

  • Are familiar with the terminology and wording insurance requires for approval for payment of a wheelchair
  • Understand kinesiology and the mechanics of posture and how to use wheelchair components to correct for weakness or deformity
  • Are up to date with new brands and features of wheelchairs
  • Understand how different wheelchair components do and do not fit together
  • Are certified by RESNA (Rehabilitation Engineering and Assistive Technology Society of North America) as Assistive Technology Practitioners (ATPs).  ATPs have taken specialized training in wheelchair and assistive technology and have passed a national examination.  They must take continuing education to keep up to date with developments in their field to maintain certification.  If you have Medicare or Medicaid for insurance, an ATP-credentialed specialist must be involved in the process.

Wheelchair Fit:  The Components

The Wheelchair Seat

Seat width and depth are two of the most important things to get right when doing a wheelchair fitting.  The seat must be wide enough to comfortably accommodate your hips without creating pressure points but snug enough to give you support and keep the overall footprint as small as possible.  By keeping your footprint small, you will be able to propel more easily and navigate tight places with greater ease.  Seat depth is equally as important.  The seat must be long enough to support your thighs but short enough that it does not rub against the back of your knees.  Correct floor to seat height will enable you to propel your chair efficiently.  If your chair seat is too low your foot plates will catch on uneven terrain and you won't be able to push effectively.  If you chair seat is too high you won't be able to sit at tables and your push will still not be effective.  And remember your pressure relieving cushion will add height to your chair as well.  Finally, the seat dump or angle at which the back of the seat tilts downward will affect your stability.  If you don't have enough dump, it will take more effort to maintain sitting balance and propel your chair.  If you have too much dump, you may create pressure points or make it harder to turn and reach while sitting in your chair.

The Wheelchair Back

Back height is another important factor to consider.  You want the back to be tall enough to give support when sitting but low enough to let you be as mobile as possible.  If you have limited trunk control, you may consider a back that offers lateral support.  Keep in mind, lateral trunk support can make transferring in and out of your wheelchair more difficult.

The Wheelchair Wheels & Tires

Wheelchairs have two sets of wheels:  the small pair in the front are casters or steering wheels; the large pair in the back are drive wheels.  The wheels and tires you choose for your wheelchair will impact the amount of vibration and speed you experience while using your chair. If you have pain and discomfort, reducing vibration will be a priority.  If you have fatigue or weakness, you will want to make the most of propulsion and speed will be important.

Types of casters:

  • Pneumatic or semi-pneumatic casters offer the wheelchair user a smoother ride, with shock absorption capabilities. However, they are also a little slower and can ultimately go flat, and thus require maintenance.
  • Solid casters are more effective at moving at speed but offer a less shock absorption and, therefore, the ride is not as smooth. They last longer because they can't go flat but are smaller and more susceptible to catch in cracks

Types of Wheels:

  • Spoke wheels look like bicycle wheels and are usually made of metal. They are usually lighter than mag wheels, but they do require more maintenance and are less suitable for moist surfaces. 
  • Mag wheels are made of synthetic materials, are almost maintenance free, but more susceptible to extreme temperatures.

Types of Tires:

  • Pneumatic tires have a shock absorbing function when going over obstacles and provide a softer ride on uneven ground. They will go flat if punctured and, without maintenance, go soft because the valves will lose air constantly over time.
  • Solid tires are almost maintenance free and they are unlikely to wear out in the life of the wheelchair.  But because they are solid, you will have bumpier rides.
  • Flat free tires are pneumatic tires that are filled with a semi-solid material. They are not subject to flats and give a softer ride than a solid tire.

Wheelchairs come in all shapes and sizes and cost upwards of thousands of dollars.  So it's important to get your wheelchair fit right.  But by choosing an experienced rehab team to help you and by thoughtfully considering your options, you can overcome the complexities and find your perfect ride.

Karen Allen Hislop is a Seating Specialist at Therapy Achievements.