A wheelchair prescription test - presenter · ‘A Wheelchair Prescription Test’ a practical...

Medical Aids Subsidy Scheme, Queensland Health

‘A Wheelchair Prescription Test’ a practical activity at the Living with Equipment in 2011 symposium, 24-25 August 2011 of 15

A wheelchair prescription test Test Answers have been added to the test questions from page 2 below

This practical exercise follows the 4 main subject areas involved in prescribing a manual or power wheelchair: Selecting wheelchairs for trial Deciding what seating will be of most benefit Measuring the user for a wheelchair Adjustments and/or set up of a wheelchair Use the equipment provided, pictures and practical activities to complete all questions _______________________________________________________________________________ Session outline and group rotation instructions Session time: 90mins 0-10mins Introduction and form groups 10-60mins Group activity: Maximum participants 4 groups (4 x 5 = 20, 4 x 6 = 24, 4 x 7 = 28)

The 15 question related to the 4 subject areas can be completed in any order. If you feel confident in answering the questions without having hands on with the equipment or by participating in group discussion, go ahead and complete the test. There is a scoring station at the end if you finish early (brief answers), or await the full answers being published in the conference proceedings to be published on the MASS website after the symposium. To complete the test by group activity and discuss all questions, the test should be performed in following order so that all participants can have hands on experience with all equipment. Note that questions 1.1, 2.2.3, 4.1, 4.2 can be completed at any time Group 1 & 2 Group 3 & 4 10-30min Station1

Equipment: 2-3 x folding MWCs 2 x rigid MWC Questions: 1.2, 1.3.1, 1.3.2. 2.2.2 3.1, 3.2.3

Station 2 Equipment: 2-3 x PWC (elev leg + recl, seat tilt) TIS MWC Questions: 1.3.3. 2.1.1, 2.2.1. 3.2.1, 3.2.2.

30-50min Station 2 questions

Station1 questions

50-60min All groups complete any unanswered questions including 1.1, 2.2.3, 4.1, 4.2

60-90mins Discussion of test answers and any related questions



1. Selecting wheelchairs for trial 1.1. Selecting a size and strength of wheelchair for trial: When considering the seat width

and strength/durability of a wheelchair to trial with a wheelchair user, indicate which of the following statements are true and which are false?

F Allowing 2.5cm at each side of the hips so the user can move within the seat and fit winter

clothing is essential for ALL wheelchair users This is an old rule of thumb that cannot be applied for all wheelchair users. It may be true when the user who is going through a growth spurt, or someone needing significant space for winter clothing. But for many wheelchair users allowing 2.5cm each side will place the push rims is a less than optimal position relative to the user and compromise self propulsion. T Significant errors can occur in measuring the width a person with a BMI of 38 or above if

measured when lying in bed. When the user assumes the sitting position in a wheelchair there can be a spread in width of the user compared to the lying posture as soft tissue is spread to the side of the hips or abdomen

True there can be significant spread in width when moving from lying to sitting due to the large amount of soft tissue T For a wheelchair user with a fixed

kyphoscoliosis and pelvic obliquity similar to that shown in the pictures here, the seat width and depth of the wheelchair may need to be larger than the actual width and depth of the user’s body dimensions. Significant lateral support and depth of backrest would be required to provide adequate postural support. You must have a clear idea of the overall sitting width and depth required to order a chair for trial

True that a minimum of 50mm each side may need to be added to seat width to provide sufficient lateral support using a moulded backrest, and at least 100mm may need to be added to seat depth – measure the user in the simulated, most stable sitting posture, aiming for a sitting posture that is achievable for all day sitting. It may be possible to not add a significant amount to seat depth if using a backrest with a cut out (i.e. customised at seating clinic) or with a backrest that can be moved backwards relative to the seat.

F Aluminium wheelchair frames are never as strong as steel frames. For a wheelchair user

who rocks back and forth in the seat, placing strong shearing forces on the backrest framework, aluminium frame wheelchairs must be avoided

Some aluminium frames are deliberately designed to flex, while others may be better reinforced than steel frames. It depends on the design principles being applied to the product in question. Blanket rules cannot be applied to the selection of materials. Products must be appraised individually.



1.2. Level of seating support and seated comfort required: For the rigid frame and folding frame wheelchairs on display at station 1, make the following measurements and comparisons

1.2.1. What is the seat angle? (Use an angle finder to measure)

Chair 1 Chair 2 Chair 3 Chair 4 7.5 deg 5 deg 6 deg 7.5 deg

1.2.2. What is the seat to back angle? (Use a goniometer to measure)

Chair 1 Chair 2 Chair 3 Chair 4 90 deg at seat to back junction, 100 at mid height bend (i.e. 10 deg bend in back cane)

90 deg at seat to back junction,100 at mid height bend (i.e. 10 deg bend in back cane)

~92 deg at seat to back junction, ~105 angle of backrest (adjustable angle mounting hardware)

82.5 deg

Note that the seat is angled downward from front to rear on each of the chairs, i.e. a positive seat angle. The backrest is near vertical on the rigid chair, but is angled back on both folding chairs. The combination of positive seat angle and a seat to back angle less than 90 degrees on the rigid chair can be referred to as a “frame squeeze”. Note that one folding chair has straight backrest frame uprights while the other has bent backrest frame uprights and one backrest can be folded in the middle.



1.2.3. Frame squeeze: For each of the statements below indicate which are true and which are

false?

F Frame squeeze will always increase pressure on the ischial tuberosities While it is theoretically true that raising the knees above the lowest point of the buttocks should increase pressure on the ischial tuberosities, this will not be the case if the user has sufficient hip flexion to accommodate the posture, and has a cushion that promotes immersion of the ischial tuberosities and loading of the thighs. In a study by Maurer & Sprigle (2004) subjects with T3 to L4 spinal cord injury tested at 0, 6.8, 10.2 and 13.7 degree seat angles, increasing the posterior angle of seat relative to the upright backrest led to no significant increase in interface pressure under ischial tuberosities or sacrum. Participants in the practical were able to feel this when seated on a cushion with firm foam under thighs and air cells under ischial tuberosities.

T Frame squeeze will increase pressure on the ischial tuberosities if the footrest is too high This will offload the thighs, regardless of the quality of the cushion. The thighs must be positively loaded by having the footrest low enough, or else the ischial tuberosities will bear an increasing proportion of the load. Loading of the thighs may be difficult to achieve in individuals with very significant muscle wasting in the lower limbs. Frame squeeze may not be appropriate if there is very significant muscle wasting AND loss of sensation, or with lower limb amputees. Frame squeeze cannot be achieved if the user has insufficient hip flexion – refer to 2.2.3 below

T Frame squeeze can make it harder to transfer out of the chair for some wheelchair users Transferring uphill can be difficult for many wheelchair users. Note though that transfers are quick while the benefits frame squeeze of increasing postural stability, promoting an upright pelvic and trunk posture with improved reach often outweigh the disadvantage to transfers. F Frame squeeze makes it harder to achieve a stable sitting posture. Having the thighs angled

upwards increases the tendency for the trunk to fall forward. Thighs should always be at 90 degrees to the trunk

Frame squeeze in isolation does not cause the trunk to fall forward. However, for a wheelchair user without active trunk muscles a squeeze frame with vertical backrest could lead to the trunk falling forward, or sense of being pushed forward if the backrest was straight (i.e. non-contoured) and support was provided above the lowest ribs – the thoracic kyphosis cannot extend back over the top of backrest, then the trunk and head would not be balanced over the pelvis, so user has a sense of falling forward. Having the thighs at <90 degrees to the trunk does not cause the trunk to fall forward. A seat to back angle of 90 degrees or <90 degrees is effective in lessening extensor spasm, with some clinicians advocating angles less than 80 degrees for strong and uncontrollable muscle tone (Mulholland, personal communication 2002)

T For a wheelchair user with sufficient hip flexion to sit in a squeeze frame, this posture may

increase stability, preventing the pelvis from sliding forward along the seat. The pelvis may be more likely to slide forward on a flatter seat

By having the trunk balanced over the pelvis along with positive support for the thighs, the pelvis is better stabilised than with a flat seat.

Frame squeeze: seat to back angle <90°



1.2.4. Backrest frame: Straight backrest frame uprights are most suitable when

A. Using a solid shell, upholstered backrest that must be removed to fold the wheelchair. The brackets that the backrest is attached to will be easier to mount to the frame and easier to use if the top and bottom brackets are set on straight tubes

B. The wheelchair user requires support only as high as curve of the thoracic kyphosis, often

around the height of the lower ribs

C. A moderate level of back support is required to allow the user to relax in the wheelchair, to support as high as the base of the scapula

D. A high level of back support is required to top of shoulders, to provide a line of pull when

mounting a chest or shoulder securement/harness

E. A, B and D above as with D a slung backrest on bent back canes is not suitable – to provide support as high as top of shoulders a padded upholstered backrest should be used

1.3. A wheelchair that is easy to mobilise in and works in the user’s home and local area: 1.3.1. The optimal seat height to propel a manual wheelchair is achieved

A. When the user is able to reach the push rim along an arc from the 10 o’clock to 3 o’clock position (i.e. looking at the right hand side, wheel moves clockwise to propel forward)

B. When the hand is dropped down to the side of the chair, the axle of the drive wheel should

be between finger tips and knuckles

C. When the push rim is grasped at the top/highest point, the arm should be flexed so there is an 80° to 100° angle at the elbow

D. When the push rim is grasped at the top/highest point, the arm should be flexed so there is a

100° to 120° angle at the elbow

E. With B and D above but possibly A also. A is dependent on the rear wheel position – a 10 o’clock start position is uncommon but is possible if the wheels are mounted at a very forward axle position. An active user with good balance skills might use such a position but would likely only get from 10 to 3 o’clock when pushing hard uphill

1.3.2. Footplate clearance and legrest angle: Inspect the 2 folding wheelchairs at station 1, one

with large front castors and 60-70 degree legrests, the other with smaller front castors, comparing these with the rigid frame chair(s) with more vertical legrests Which wheelchair requires the greatest allowance for footplate clearance to prevent the footplate bottoming out when descending a kerb/footpath-to-gutter ramp? Chair 2. The further the footrest project in front of the castors, the greater the footplate clearance required

Which wheelchair will allow the lowest seat to floor height for a tall wheelchair user? Chair 1. Chairs with 60-70 degree legrests allow a lower seat to floor height for a tall wheelchair user compared to using vertical 90 degree legrests.



Which wheelchair will provide the most stable lower limb resting position for a wheelchair user who experiences extensor thrust spasm when going over sudden bumps or rough ground? Chair 4 and possibly 3 also. Both chairs have footplates positioned so the knee will be flexed close to 90 degrees. When the knee is closer to 90 degrees the balance between knee extensors (quadriceps) and knee flexors (hamstrings) is at its most neutral in sitting, less likely to see quads contact uncontrollably as can occur after a trigger such as a sudden bump. When the knee is at a more open angle >90 degrees there is a greater tendency for the quads to contract leading the extensor thrust. Chair 3 has a seat to back angle >90 degrees to accommodate a wheelchair user with a fixed posterior pelvic tilt, while chair 4 has a seat to back angle <90 degrees to suit a user with good hip flexion range. Chair 4 will provide greater inhibition for extensor thrust spasm since the muscles that attach across BOTH the knee and hip joint are positioned in more flexed postures, therefore less likely to produce extensor thrust spasm.

Which wheelchair requires the most turning space indoors? Chair 2 has the longest overall length

1.3.3. Effective powered mobility: Due to the wide variety of power wheelchair users with

different levels of function, driving skills, local terrain, etc, there is a wide variety of power wheelchairs on the market to suit. Different wheelbases (mid, front or rear wheel driven) controls, motors, etc are available to suit the diversity of user needs. Consider the power wheelchairs at station 2 to decide which of the following statements are true and which are false?

T More ground clearance is required under the base of this rear wheel drive chair than the mid

wheel drive chair. The distance between wheels and front and rear stabilisers on the mid wheel drive is less than the distance between castors and wheels on the rear wheel drive

The distance between wheels is greater on rear wheel drive chairs therefore they require more ground clearance to clear rough ground. F If the manufacturer’s brochure states that the chair can go 20km on full batteries, then the

chair should be expected to travel that distance in a single trip. If the chair does not travel the full 20km the user should contact MASS to request a service

20km is a guide of the maximum distance the chair can be driven under ideal testing conditions, possibly on a set of rollers in a factory in temperature controlled conditions. Power wheelchair repairers report high call out rates on hot days with wheelchair users trying to drive several kilometres in the heat of the day. A power wheelchair is not a replacement for a motor vehicle. Motors can quickly overheat if run at maximum speed over several kilometres. They are designed for shorter distance running of only a few kilometres at a time. Batteries must be fully charged. The first hour of charging de-gasses the battery and prepares the battery for charging. The first 4 hours is the main charging period but many batteries need 8-12hours of charge to reach their maximum capacity.



F Mid-wheel drive chairs are harder for everyone to learn to drive; they can fish tail at speed

risking a crash Fish tailing may have been a factor with early FRONT wheel drive chairs but is not usually an issue even at high speeds with current mid-wheel drive designs. Most mid-wheel drive designs are easier to learn to drive as the user moves the joystick at the time of lining up with a doorway/90 degree turn. T Rear wheel drive chairs are generally more difficult to drive indoors than mid-wheel drive

designs Rear wheel drive chairs require more anticipation of upcoming 90 degree turns into doorways, etc. Indoors the user must make allowance for the chair to swing from the axis of rotation at the rear wheel axles (i.e. one rear wheel turns in one direction, the other the opposite direction to make the chair turn) which requires some driving experience to master. F If the wheelchair user is concerned about losing traction on steep and slippery hills, or

grassy areas in parks, rear wheel drive chairs will not perform as well as mid-wheel drive chairs – the weight of the wheelchair user loads the drive wheels in mid-wheel drive designs

The weight of the user may be more than the weight of the chair, and since they are seated up above the wheels, the force created by their weight will move back behind the drive wheels, loading the rear end of the chair when driving up steep hills. Many mid-wheel drives have significant weight over the drive wheels or in front of the drive wheels (e.g. battery box at front) to counteract this effect and improve traction, so they perform surprisingly well. However, since a rear wheel drive gets traction from the rear, they can outperform mid-wheel drives on steep and slippery terrain. T A mid-wheel drive design with quite limited vertical travel in the rear

stabiliser wheels could be subject to drive wheel “hanging” (drive wheels off ground, front and rear stabilisers on ground) if the user approaches a steep kerb ramp front on. It may be possible to work around this problem by approaching the kerb at an angle

Approach at an angle is quite successful in preventing drive wheel hanging/loss of traction.

T For a wheelchair user living in an area with steep, hilly or softer terrain (such as sandy soils),

it is important to know how well the controller, motors and batteries will be able to drive the chair. The controller must provide sufficient power to motors which must produce sufficient torque, and batteries must have enough capacity to provide current to the system and sufficient drive distance

Do not make any assumptions about a chair based on its performance indoors at a trial. Steep hilly or soft soils impose much higher loads and as far as possible the chair should be trialled in all anticipated driving conditions. Some wheelchair users report the disappointment of obtaining a new chair, only to find it does not drive as well uphill as their previous chair. They have been caught by a newer looking design offering improved appearance and/or features, except that the motors and/or controller do not produce the same power as their previous chair. If in doubt when comparing chairs, check how many amps the controller will provide to the motors, how many amp-hours the batteries are rated at, and how many Newton metres of torque the motors produce – these technical details should be available but can be challenging to source from all dealers. F For a 2 ½ year old child who has demonstrated no interest or ability to use a one arm drive

manual wheelchair, it is not possible to provide safe learn to drive experiences in a power wheelchair. A 2 ½ year old is too impulsive and cannot understand the consequences. Also, a longer effort should be maintained to aim for even a small amount of independence in a manual wheelchair

Persisting with manual mobility when there has been no progress may be at the expense of other developmental goals, particularly the need to independently explore the environment, play, socialise and communicate. If one arm drive was the only viable manual mobility option, it would be extremely



unlikely that it would lead to independent outdoor mobility, as one arm drive wheelchairs are notoriously difficult to control on uneven ground. Independent and safe powered mobility can be facilitated by the use of a chair with seating and controls suited the user, with a remote cut out switch as an accessory – the latter allows a carer/supervisor to immediately stop the chair if the user drives toward a hazard / collision. Remote cut out switches can be fitted to all major brands of power wheelchair controls by a third party specialist repairer in Brisbane, though other options may be possible. T Power wheelchair programming is a critical element in trialling a power wheelchair.

Parameters in the drive program, such as forward acceleration and deceleration affect the jerkiness of driving so should be adjusted to the driving skills and experience of the user. How the joystick functions can also be programmed, for example pulling back to drive forwards when driving with a chin joystick, or joystick damping to ignore spasm

Programming should always be set up for the individual user. At times a chair may be too jerky with forward acceleration and deceleration set up to be too responsive for the individual’s driving skills/experience. A wheelchair dealer should always be willing to make changes at a trial – changes to the drive program can often be performed in less than 10 minutes. 2. Deciding what seating will be of most benefit 2.1. Seat tilt for pressure relief 2.1.1. To restore the flow of blood and lymphatic fluids in soft tissue over the ischial tuberosities

after a prolonged time in sitting to UNLOADED LEVELS (i.e. same as if the person had stood up), which of the following is most effective?

A. Lift the body clear of the seat for 30 seconds

B. Lift the body clear of the seat 90 seconds

C. Lean forward so the chest rests on the knees for 90 seconds

D. Lift the body clear of the seat, or lean forward at least as far as elbows rest on knees, for 2-3

minutes

E. Tilt the seat of the wheelchair to the rear by no less than 45 degrees, possibly as much as 65 degrees

F. Either D or E above. Henderson (1994) compared pressure relief using 3 manoeuvres: leaning the trunk to 45 degrees forward of upright, tilting the seat 35 degrees to the rear, and 65 degrees of rearward seat tilt. The point of maximum pressure and pressure under ischial tuberosities was measured via interface pressure mapping. The forward lean produced a 70-78% reduction in pressure while the 65 degree seat tilt produced a 36-47% reduction in pressure and both were statistically significant; while the 35 degree tilt did not produce a significant reduction (17-27%). Coggrave and Rose (2003) measured transcutaneous oxygen tension (TcPO2) at one ischial tuberosity to determine how long the traditional pressure lift (lifting body clear of seat using upper limbs) would take to restore blood flow to unloaded levels with 48 subjects with cervical to lumbar level spinal cord injuries. They found the traditional 30 seconds was not effective, while the average time for all subjects to restore TcPO2 to unloaded levels was 1min 51 seconds, some subjects taking over 3 minutes. In all of their measurements they found the forward lean provided the most effective pressure relief as demonstrated by TcPO2 and interface pressure mapping in their specialist seating clinic. We can conclude that no one strategy can effectively relieve 100% of pressure to fully offloaded level; but forward leans and very large seat tilts, up to 65 degrees, have been demonstrated to be most effective.



2.2. Postural assessment and trial of seating prior to finalising an order can help decide what

seating will be of most benefit. But it is not always easy to get the wheelchair user out of their chair or to trial all equipment options at the one appointment.

2.2.1. Which of the following statements about strategies to reduce swelling in lower limbs are true and which are false?

F Elevation of legrests to the level of full knee extension is very effective in reducing

swelling/oedema in lower limbs It is well known that the lower limb must be elevated to the level of the heart or above that level to provide a significant reduction in oedema. Raising the legs using a footstool or elevating legrests on a wheelchair may improve comfort, providing a stretch for the hamstrings. T Legrest elevation and backrest recline used together may be

more effective in raising the lower limbs high enough to reduce oedema

If the backrest is fully reclined so the trunk is near horizontal with legrests fully elevated, this posture brings the lower limbs closer to the level of the heart, so it may be more effective. Most wheelchair

users will not tolerate a full lying posture for long, and strong shear force may act on the skin over the spine and pelvis when returning the backrest to the upright position, risking skin friction or pressure injury for those at risk. Combining seat tilt with backrest recline and legrest elevation may be more effective: tilt the seat at least 20 degrees to the rear, then raise legrests and recline the backrest to get lower limbs above heart level; to return to upright, raise the backrest first, then lower the seat from the tilted position to prevent the backrest pushing the user forward along the seat as the backrest is raised. T 50° tilt in space can achieve high level leg elevation so could

be used to reduce oedema Clearly demonstrated in the photo opposite. As with large recline discussed above, will a wheelchair user tolerate this posture for long? Seating functions may provide some benefit in reducing oedema but other strategies such as compression therapy may well be more effective.

50° seat tilt 2.2.2. Very low backrest heights can be ordered, some as low as 250mm above the seat

framework, so there can be some concern as to whether a low back will provide sufficient postural support, particularly for a wheelchair user with limited trunk muscle function where there is a risk of deformity in the long term. The lowest backrest height that should be recommended for a long duration wheelchair user without full trunk muscle function is to support as high as?

A. The base of the scapula, to prevent the inferior angle of the scapula from rubbing on the

backrest while propelling the chair

B. The lowest 2 ribs would be the moderately conservative view, thus allowing the thoracic kyphosis to extend back above the height of the backrest. A vertical or near vertical backrest to this height acts as a lumbar support (Hastings 2000 & 2003)

C. The posterior superior iliac spine at the top/back of the pelvis if the wheelchair user is very

active, reaching and moving frequently

D. Both B and C above



2.2.3. Several assessments can be recommended for long duration wheelchair users without full

trunk muscle function. Mat assessment can be used to check range of movement with without gravity. Sitting unsupported, without a backrest can be used to observe self-adopted posture and the effect of gravity. Sitting in the trial seating is necessary to determine if it will work. Testing knee extension and true hip flexion are two of the most highly recommended assessments and are illustrated in the pictures below

Which of the following statements about seating assessment and trial are true and which are false? F If the knee can be fully extended in a recliner lounge chair in

hospital (no knee contractures obvious) you can be 100% confident the user will be able to achieve full legrest elevation in a power wheelchair. No, the recliner has an open seat to back angle when the legrest is raised and lots of soft padding to “soak up” any limitations to the user’s range of motion.

T Since the hamstring muscles are attached from pelvis to lower leg, both knee extension and true hip flexion must be assessed to determine if legs can be fully elevated. Yes, the hip must be flexed to the angle that the actual seat to back angle will be on the chair that will be ordered, then the leg is extended to check if full extension of the knee joint is possible

T Testing true hip flexion can be used to determine if the

wheelchair user can trial a chair with both: a seat angle/slope of 15° toward the rear of the seat, and a vertical or near vertical short height backrest Yes, many long duration wheelchair users will not have sufficient hip flexion to allow a squeeze frame with ~ 15 degree seat angle, seat to back angle ~ 75 degrees as shown in the picture at right.

F When trialling seating it is important to start with the most severe postural problems, such as loss of head control. By stabilising the head first, the wheelchair user is more comfortable and relaxed, then support for the pelvis and lower limbs should be contemplated. Always start with the pelvis as this provides the base for stability, then the lower limbs and trunk, finishing with the head. A complex/expensive headrest may not be required if abnormal muscle tone can be controlled by other seating first.

ASIS

PSIS

Test of true hip flexion: Move thigh toward chest; pelvis lifts when reach limit of hip flexion



F When providing foot support for a child less than 5 years of age, the important thing is not to give up on their capacity to weight bear in standing. Sandal or shoe holder style footrests are the only effective way to prevent ankle rotation or foot drop deformity and should always be trialled first with such a young wheelchair user. Securements that attach around the ankle are not effective in preventing rotation or foot drop.

No, it is best to start with the least restrictive foot securement as static foot positioning is not appropriate for many wheelchair users. Attachment around the ankle, holding the ankle down on the footplate may prevent rotation and can certainly prevent foot drop (plantar flexion) if secured properly, while allowing the user to move the front of foot somewhat. At times shoe holders will be required to prevent rotation at the ankle and this can be particularly important when walking and standing goals are important for the wheelchair user.



3. Measuring the user for a wheelchair 3.1. Providing the correct dimension when specifying seat width: Using the 2 folding frame

wheelchairs at station 1, decide which of the statements below are true and which are false? T The manufacturer of the wheelchair will always make/provide a

wheelchair with an outside frame width that is equal to the seat width specified on the wheelchair order form. Outside frame width = seat width on order form for all known wheelchair manufacturers

F The width of the upholstery, from the outside edges of the seat rails, is always the seat width and the frame width of the chair. If you trial a chair and the seat width fits the user really well, measure the width of the seat upholstery and write that dimension down as the seat width to be ordered. See below where width of seat upholstery < outside frame width

T The width of the upholstery is not always the same as the seat width. With most wheelchairs the seat rails sit directly on top of the side frame members so with these the seat width equals outside frame width. But with some makes the seat rails sit within the side frame members of the wheelchair. In the latter case, if the chair fitted really well and you measured the width of slung upholstery and specified that as the seat width, the chair would be too small. You have not included the extra 40-50mm width of frame that the user was actually sitting on when trialling the chair. Take care to avoid this error; the chair may be unusable due to the poor fit on delivery.

3.2. Allowance for seat width and depth variations on the user measurements: Inspect the

power wheelchair with an accessory backrest at station 2. 3.2.1. How much depth has been added to the measurement of the wheelchair user’s sitting depth

by fitting this accessory backrest? ~20mm on Traxx; ~110mm on Quantum 600. The backrest on the Traxx can move forwards backwards as it has 2 pivot joints in the backrest adjustment, while the backrest on the Quantum 600 was fixed at the base with angle adjustment from a single pivot joint. Also, the mounting brackets are set up in opposite directions, facing forwards on the Quantum 600 and backwards on the Traxx. This demonstrates how the Jay 3 backrest fitted to both wheelchairs required a significant amount of seat depth on the Quantum 600, but very little seat depth on the Traxx. It is essential to know how much space is needed to fit an accessory backrest or the seat may be too short for the user once the backrest is fitted.

Jay 3 back in Quantum 600

Jay 3 back in Traxx



3.2.2. How much width has been added to the measurement of the wheelchair user’s sitting width

to provide lateral support using this accessory backrest? ~50mm each side on both chairs. So 100mm had to be added to the seat width to use the Jay 3 backrest fitted to both wheelchairs.

3.2.3. Inspect the manual wheelchair with slung backrest upholstery fitted to back of the backrest

frame uprights at station 1. You measured seat depth with the wheelchair user seated in a realistic/sustainable sitting posture on a plinth. You are concerned about the risk of pressure injury so you want to maximise the contact area available in sitting – you subtract only 20mm from the measurement of the user’s sitting depth. Would the manual wheelchair with upholstery attached to back of frame fit the user on delivery?

No, it will be too long in the seat. May compromise circulation by the seat sling pressing in the popliteal fossa behind the knee, or cause the user to sit forward with the pelvis tilted back. It is always safer to subtract 50mm from the measurement of the user’s sitting depth, from back of upright pelvis to knee crease to avoid such an error, or to measure seat depth in the trial wheelchair so that the allowance for upholstery variations (i.e. attached to front Vs back of backrest frame) is known prior to specifying the final measurements on the wheelchair order form.

Jay 3 back in Quantum 600

Jay 3 back in Traxx



4. Adjustments and/or set up of a wheelchair:

Use a manual wheelchair to simulate the upper limb tasks in questions 4.1 and 4.2 below 4.1. Causes of shoulder pain in long duration wheelchair users: A significant percentage of

long duration wheelchair users with spinal cord injury (30-60%) experience shoulder pain (PVA 2005). Radiographs have been used to identify osteolysis of the distal clavicle in long duration wheelchair users with spinal cord injury; MRI studies used to confirm rotator cuff tears, and an associaton between shoulder pain and BMI established in the research literature (Boninger 2001). Escobedo et al (1997) demonstrated by MRI the primary defect to the rotator cuff tendon was in supraspinatus. In studies measuring forces at the shoulder during propulsion (Mulroy 2005, Mercer 2006) coracoacromial ligament oedema and thickening was associated with higher superior, posterior and abduction forces at the shoulder. Propulsion studies have found that forward axle position is associated with lower peak forces, less rapid loading of the pushrim, fewer strokes to go at the same speed and contact with more of the push rim with each push stroke (Boninger 2000, Mulroy 2005).

Which of the following cause or contribute to shoulder pain?

A. Transfers are to blame as the upper limbs were never designed for weight bearing. Weight

bearing transfers where the leading upper limb is placed in abduction and internal rotation, in a position that is far away from the trunk (i.e. in shoulder extension, as with a transfer to car seat) is a high risk activity for impingement of structures within the subacromial space

B. Repetitive weight bearing related to wheelchair propulsion with elevation and abduction of

the humerus is to blame. After finishing a push stroke, to return the hand to grasp the push rim and push again, many wheelchair users lift the hand to the height of the push rim, resulting in repetitive elevation and abduction. As the most frequent activity involving the upper limbs, repetitive elevation and abduction of the humerus during wheelchair propulsion is a major factor causing shoulder pain. This is consistent with a superior translation of the humerus via the action of supraspinatus, with subacromial compression.

C. If the seat height is too low for the wheelchair user then the shoulder to push rim relationship

is not in the optimal set up. The aim should be to avoid repetitive elevation and abduction of the humerus when propelling

D. Dropping the hand down below the level of the push rim when returning the hand to grasp

and push off again. The shortest upper limb motion that is possible to return the hand to grasp the push rim should be used – avoid unnecessary excursions of the upper limb during propulsion

E. All of the above

F. A B and C above – the detail of the answer is contained in each of the above statements



3.3. Efficiency of propulsion: For a wheelchair user with large abdominal mass (i.e. weight

carried forward of the front of the pelvis) who is having difficulty pushing a manual wheelchair

A. Consider switching to a tilt in space wheelchair and pushing the chair with the seat tilted to

the rear slightly. Some tilt in space chairs can be ordered with 24” diameter rear wheels to enable easier self-propulsion than traditional tilt in space wheelchair designs with smaller rear wheels.

B. Try a different rear wheel position first. Moving the axle forward places more user weight on

the rear wheels of the chair, less user weight on the front castors. Since large diameter rear wheels have less rolling resistance than small diameter front castors, the chair will be easier to push.

C. Try a lighter weight wheelchair. The weight of the wheelchair is the most significant factor in

making the wheelchair easy to push

D. B and C above only

References Boninger M.L, Towers J.D, Cooper R.A, Dicianno B.E, Munin M.C. (2001) Shoulder imaging abnormalities in individuals with paraplegia. Journal of Rehabilitation Research and Development, 38(4), 401-408 Boninger M.L, Baldwin M.A, Cooper R.A, Koontz A.M, Chan L. (2000) Manual wheelchair pushrim biomechanics and axle position. Archives of Physical Medicine and Rehabilitation 81, 608-613 Coggrave M.J. & Rose L.S. (2003) A specialist seating assessment clinic: changing pressure relief practice. Spinal Cord, 41(12), 692-695. Escobedo E.M, Hunter J.C, Hollister M.C, Patten R.M, Goldstein B. (1997) MR imaging of rotator cuff tears in individuals with paraplegia. American Journal of Roentgenology 168(4), 919-23 Hastings J.D. (2000) Seating Assessment and Planning. Physical Medicine & Rehabilitation Clinics of North America, 2000 Feb; 11 (1), 183-207 Hastings J.D, (2003) Wheelchair configuration & postural alignment in persons with spinal cord injury. Archives of Physical Medicine and Rehabilitation, 84(4). Henderson J.L, (1994) Efficacy of 3 measures to relieve pressure in seated persons with spinal cord injury. Archives of Physical Medicine and Rehabilitation, 75 (5), 535-9. Maurer C.L, Sprigle, S. (2004) Effect of seat inclination on seated pressures of individuals with spinal cord injury. Physical Therapy, 84(3), 255-261. Mercer J.L, Boninger M, Koontz A, Ren D, Dyson-Hudson T, Cooper R.A, (2006) Shoulder joint kinetics and pathology in manual wheelchair users. Clinical Biomechanics 21, 781-789 Mulroy S.J, Newsam C.J, Gutierrez P.T, Requejo P, Gronley J.K, Lighthall Haubert L, Perry J. (2005) Effect of Fore-Aft Seat Position on Shoulder Demands During Wheelchair Propulsion: Part 1. A kinetic Analysis. Journal of Spinal Cord Medicine 28(3) 214-221

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