Wheelchair Fitting

Introduction

Wheelchair fitting is the sixth step in the key steps to wheelchair service delivery.  Fitting entails trial of the wheelchair by the user and final adjustments to ensure the wheelchair is correctly assembled and set up. During the fitting, the wheelchair user and personnel together check that:

  • the wheelchair is the correct size and all the necessary modifications and adjustments have been made to ensure an optimum fit;
  • the wheelchair and cushion support the wheelchair user in sitting upright;
  • if a pressure relief cushion has been prescribed, the cushion really relieves pressure.

A properly fitted wheelchair provides comfortable seating and good back support, improving posture and ultimately optimizing function. It has been estimated that 80-90% of individuals are not properly fitted in their current wheelchair as their bodies and needs change over time. A wheelchair that does not fit properly may lead to pressure ulcers, poor posture, reduced balance, difficulty propelling the wheelchair, and difficulty with transfers. The ideal sitting position for most people in a wheelchair follows the 90-90-90 rule;

  • 90° bend in the hips
  • 90° bend in the knees
  • 90° bend in the ankle

Wherever possible, the same person who carried out the assessment should carry out the fitting. A wheelchair fitting for a wheelchair user who needs additional postural support takes longer because additional fittings may be needed. Always check the fit with the wheelchair stationary, and then while the wheelchair user self-propels or is pushed.

Process

Wheelchair fitting should always be carried out in the following order: check size and adjustments, check posture, check pressure, check fit while the wheelchair user is moving.

Check Size and Adjustments

Seat Width; A correct fit should fit closely. Run your fingers between the outside of the user’s thighs and the sides of the wheelchair. Your fingers should fit comfortably without being pinched. Make sure the sides of the wheelchair do not press into the wheelchair user’s legs. This is particularly important for a wheelchair user who cannot feel pressure on the thighs (does not have normal sensation). Firm pressure on thighs from the side of the wheelchair could cause a pressure sore.

Seat Depth; A correct fit should have a two-finger gap (30 mm) between the back of the knee and the cushion. It gives the thigh good support which will reduce pressure under the seat bones and helps to stop pressure sores. Check that the wheelchair user is sitting upright and then slide hand between the cushion and the back of the knee, there should be a gap large enough to admit two fingers. There may be a bigger gap for wheelchair users with long legs, up to 60 mm is acceptable. Slide hand down the back of the calf and make sure it is not touching the seat or cushion. Always check both sides.

Footrest Height; For a correct fit, the thighs are fully supported on the cushion with no gaps and the feet are fully supported on the footrests with no gaps. Check by sliding hand between the thigh and the cushion. There should be even pressure along the thigh and no gaps. Look at each foot on the footrest. The foot should be supported at the front and the back with no gaps. If there are gaps under the thigh, the footrest may be too high. If there are gaps under the foot, the footrest may be too low.

Backrest Height; The correct fit should give the wheelchair user the support needed and allow an active person the freedom to move the shoulders to push. Check by observing whether the trunk is balanced over the hips and ask the wheelchair user whether the backrest is comfortable. Also check that the wheelchair user able to push the wheelchair without the backrest interfering.

The height of the backrest depends on the needs of the user. Wheelchair users who push themselves need a backrest which allows their shoulders to move freely. Wheelchair users who have difficulty sitting upright may need a higher backrest which gives more support to the spine. During the assessment process there are two backrest height measurements on the wheelchair assessment form, always ensure both measurements are taken, as sometimes it is not clear in the assessment which height backrest will be most comfortable for the wheelchair user.

A backrest which provides support up to the bottom of the wheelchair user’s rib cage is a good height if the wheelchair user:

  • is fit and active;
  • can sit upright easily with good balance;
  • will be actively propelling themselves and needs good freedom of movement.

A backrest which provides support up to the bottom of the wheelchair user’s shoulder blades is a good height if the wheelchair user:

  • is likely to get tired quickly, e.g. elderly or with a progressive disease;
  • has some difficulty sitting upright.
  • this backrest height still allows some freedom of movement around the shoulders for the wheelchair user to propel the wheelchair with the arms.

Rear Wheel Position for Hand Propulsion; Is correctly fit if the user’s elbows should be at a right angle when hands are placed on the push rims. Ask the wheelchair user to grip the push rims at the top of the wheels. The elbow should be bent at 90 degrees. Also check with the user if the rear wheels are positioned correctly for balance (forward for active, back for safe).

Seat Height for Foot Propulsion; With the wheelchair user sitting upright, and the back of the pelvis comfortably supported by the backrest, he/she should be able to rest the feet flat on the floor. Check by asking the wheelchair user to sit with the back of their pelvis against the backrest with the pushing foot flat on the floor. Check whether the feet can sit flat on the floor. If the seat height is too high, wheelchair service personnel can try:

  • reducing the height of the cushion;
  • attaching a solid seat lower than the original seat (get technical advice or support to do this).

For a user who is propelling with only one foot, with the other foot resting on the footrest - check the pressure under the seat bone of the side that is resting on the footrest

Check Posture

Observe how the wheelchair user is sitting in the wheelchair from the side, and from the front. Is the user sitting in an upright posture? Some wheelchair users like to have their feet tucked in underneath them. some wheelchair designs allow for this. if the wheelchair user is comfortable and feels balanced, this is fine.

Check Pressure

For every wheelchair user at risk of developing a pressure sore, check if the pressure under the seat bones is safe.

Check Fit while the Wheelchair User is Moving

The final part of fitting is to check how the wheelchair fits when the wheelchair user is moving. If a wheelchair user cannot push the wheelchair independently, ask a family member/caregiver to push the wheelchair. You should look out for:

  • Backrest; Should give enough support and allow the wheelchair user freedom to move the shoulders to push
  • Rear Wheel Position; Should allow positioned correctly to allow the user to push
  • Seat Height and Depth; Should be correct for the wheelchair user to push with their legs
  • Posture Supports; Should allow for unrestricted and safe wheelchair mobility
  • Footrest; User’s feet should stay on the footrests
  • Movement of the Wheelchair; Movement or pushing should not cause the wheelchair user to change their posture or feel uncomfortable or unstable in any way.

Wheelchair Fitting Checklist

  • Is the wheelchair ready?
  • Check size and adjustments
  • Check posture
  • Check pressure
  • Check fit while the wheelchair is moving

Problem Solving

Sometimes personnel will find a problem with making the available wheelchair fit the wheelchair user correctly. The problem may be because there is a limited range of wheelchairs and sizes available or that the wheelchair user needs extra support to sit upright comfortably. Below are some simple solutions to some common problems. Making modifications and providing more postural support is covered in much greater detail in the intermediate-level training. All of these solutions assume that the closest-size wheelchair for the wheelchair user has already been selected from those available. Always check this before modifying a wheelchair.

Seat Depth Too Short

If the seat depth (front to back) is more than 100 mm shorter than the wheelchair user’s seat depth (for an adult), this is a problem. The wheelchair user will not have enough support from the seat to be able to sit comfortably. Pressure relief is also reduced. The seat depth needs to be lengthened.

  1. Lengthen the wheelchair seat depth by extending the seat rails and replacing upholstery;
    • If the wheelchair is a folding-frame type, check whether the seat rails are “dedicated”. This means the seat rails are not also part of the wheelchair frame.
    • In this case, an extension can be made to the seat rails and new upholstery made to the correct length.
  2. Lengthen the wheelchair seat depth by replacing the upholstery.
    • If the wheelchair is a rigid frame wheelchair with upholstery, check if the seat rail extends beyond the seat. In this case, it may be possible to replace the seat upholstery with new upholstery made to the correct length.
  3. Lengthen the wheelchair seat depth by adding a rigid board with a cushion.
    • A solid seat can be made from wood, plastic or any other rigid material which will not flex or crack.
    • The seat can be fixed to the top of the seat rails. Add a cushion that is the same width and depth as the new seat.
    • Ensure the new seat is strong enough to carry the weight of the user. Check that the seat does not flex or crack beyond the existing wheelchair seat.
    • Always ensure a rigid seat is provided with a cushion for every wheelchair user.
    • Check during fitting that the backrest and footrests are the correct height. The solid seat and the cushion will raise the wheelchair user in the wheelchair.

Seat Depth Too Long

If the shortest available seat depth is too long, it will be impossible for the wheelchair user to sit upright. The seat depth needs to be shortened. Shorten the wheelchair seat depth.

  • Mark the seat depth that is needed on the existing seat.
  • If the seat is upholstered: remove the upholstery, shorten it (using an industrial sewing machine) and replace.
  • If the seat is rigid: remove the seat, shorten and replace.
  • Shorten the cushion to match the new seat depth.
  • When cutting a rigid seat – always ensure that all edges are smooth and splinter-free.
  • When cutting a cushion – always cut from the front, so that pressure relief at the back of the cushion stays the same.

Footrests Height Too Low

If the footrests height is too low, the wheelchair user will not be able to rest the feet comfortably on the footrests. This can cause him/her to slide forward in the wheelchair, or to feel unstable. There will not be enough support to sit upright comfortably. The footrests will need to be raised.

  1. Raise the footrests height by – shortening the footrests hanger.
    • On most four-wheel wheelchairs, the footrests hanger can be cut shorter. Always check that the adjustment mechanism is still working.
  2. Raise the footrests by – building up the footrests
    • Use wood or another sturdy material to add height to the footrests. Check that the build-up does not stop footrests that move out of the way for transfers from working.

Footrests Height Too High

If the footrests height is too high, the wheelchair user’s thighs will not rest comfortably on the seat. Footrests that are too high can increase pressure on the seat bones. The footrests will need to be lowered.

  1. Lower the footrests by – lengthening the inner extension tube.
    • Check if the inner extension tube can be replaced with a longer tube. If so – replace it with a similar tube of the same diameter and strength.
    • Make sure the footrests do not become so low that they catch on the ground. If this happens, try option 2 instead. If this does not work, the wheelchair is not suitable for the wheelchair user.
  1. Increase the height of the cushion.
  • Increase the height of the cushion or raise the cushion by adding something solid underneath.
  • Do not use soft foam to increase the height of the cushion. This will compress, and will also feel unstable.
  • Check during fitting that the backrest is the correct height. The higher cushion will raise the wheelchair user in the wheelchair.
  • Check that there are no functional problems with raising the cushion. For example – the wheelchair user may then not be able to fit under tables or desks.

Legs Roll Inwards or Outwards

Sometimes the wheelchair user’s legs roll inwards or outwards. This may be because of the way they are used to sitting, or have a physical reason (for example muscle weakness). simple adjustments to the wheelchair seat or cushion can help to reduce this problem.

  1. Double check the footrests height.
    • Make sure the footrests height is supporting the wheelchair user correctly (even pressure should be felt under the feet and under the thighs).
  2. Check the seat is properly tensioned.
    • If the wheelchair has an upholstered seat – make sure that the seat is tensioned firmly. 
    • If the seat is saggy, this will encourage the wheelchair user’s legs to roll inwards.
  3. Add wedges to the cushion to support the thighs in neutral (as in DVD and illustration) or provide a contoured cushion, modify cushion if necessary.
    • Some contoured pressure relief cushion shave a rise between the thighs,which will help to keep legs comfortably apart. The rise can be increased to provide additional support if needed.
    • Some contoured pressure relief cushions have “gutters” for the legs to rest in. The edges of the gutter can be increased to stop legs from rolling outwards.

Feet Tend to Slide Off The Footrests

Sometimes the wheelchair user’s feet slide off the footrests. This often has a physical reason, for example muscle weakness or muscle spasms.

  1. Double check the footrests height.
    • Make sure the footrests height is supporting the wheelchair user correctly (even pressure should be felt under the feet and under the thighs).
  2. Adjust the footrests angle (if possible).
    • Check if the footrests angle can be adjusted. If so – try increasing the angle of the footrests. This may help to hold the wheelchair user’s foot in place.
    • Check that there is still even pressure under the foot.
  3. Add a Strap
    • Attach a strap to the footrests hangers at the level of the ankles.
    • If the feet tend to slide off backwards, the strap goes behind the legs.
    • If the feet tend to slide off forwards, the strap goes in front of the legs.
    • Make sure the strap is easy to remove, so that the wheelchair user can get in and out of the wheelchair without effort.
    • Check that the wheelchair user can reach the strap without assistance, and can do it up and undo
    • A calf strap can help to keep a wheelchair user’s legs in place. Straps at the back of the foot can provide more support, helping to prevent a wheelchair user’s legs from sliding off the back of the footrests.

Wheelchair is Too Wide

Sometimes the smallest wheelchair available is still too wide for the wheelchair user. if the wheelchair seat is too wide, the wheelchair user will find it difficult to sit upright, and is likely to collapse to one side. some simple foam inserts can help to provide the wheelchair user with support to sit upright.

  1. Add foam inserts on each side of the pelvis.
    • Measure the space between the wheelchair user (sitting central in the wheelchair with the back against the backrest) and the side of each armrest.
    • Cut and add foam inserts to fill the space between each side of the wheelchair user and the side of the wheelchair.
    • Check fit.
    • Upholster and attach the foam inserts. If the armrests are solid, the inserts may be attached to the armrests. They may also be attached to the top of the cushion.
    • The inserts only need to come as far forward as the user’s trunk.
    • Ensure the cushion matches the seat width.
    • If the wheelchair is very wide, the wheelchair user will also have trouble reaching the push rims. Overreaching for the push rims can cause a shoulder injury. Consider carefully whether the wheelchair is safe for the wheelchair user before prescribing (selecting) it.

Good Practice

Resources

Rosen L. Fit to Function: Four Areas Where Function can be Improved by Selecting the Proper Fit of the Manual Wheelchair. Rehab Management: The Interdisciplinary Journal of Rehabilitation [serial online]. November 2010;23(10):14-15.

Sprigle S. Measure it: Proper Wheelchair Fit is Key to Ensuring Function while Protecting Skin Integrity. Adv Skin Wound Care. 2014;27(12):561-572.

References

  1. Assistive Technology for All. WSTP Basic Video Series: 14. Fitting Demonstration. Available from: https://youtu.be/JzMPwnWPj_0[last accessed 30/06/18]
  2. Assistive Technology for All. WSTP Intermediate Video Series: 16. Fitting Demonstration - Deepak. Available from: https://youtu.be/Dy6quaGh9Xc[last accessed 30/06/18]
  3. Assistive Technology for All. WSTP Intermediate Video Series: 17. Fitting demonstration - Careen. Available from: https://youtu.be/pINSowK0TmU[last accessed 30/10/17]
  4. William Armstrong, Johan Borg, Marc Krizack, Alida Lindsley, Kylie Mines, Jon Pearlman, Kim Reisinger, Sarah Sheldon. Guidelines on the Provision of Manual Wheelchairs in Less Resourced Settings. World Health Organization; Geneva: 2008.