Shoulder Overuse Injuries And The Use Of Power
Assist Wheelchairs.
Jacinta Maurin
Use of wheelchairs within the community is on the increase
(13) and associated with this is a staggering incidence of
over use injuries and shoulder pain. (2) The purpose of
this review is to look at the incidence of shoulder pain in
wheelchair users and present the options available in power
assist push rims. A case study and survey of Power Assist
users will be discussed.
The incidence of shoulder pain varies in the literature but
generally survey studies of manual wheelchair users report
a prevalence of shoulder pain between 31-73 percent. (2)
Because wheelchair users rely on their arms for mobility,
transfers, activities of daily living and pressure relief
maneuvers shoulder injuries can be devastating to quality
of life. (2) Hand rim wheelchair propulsion has been
implicated as a contributor to several overuse injuries of
the upper limbs. (7)
When making the choice between a power and a manual
wheelchair, the rehabilitation team and end user carry out
a detailed assessment looking at the pros and cons of both.
The main advantages of manual wheelchairs, for those
individuals capable of propelling them, are that they are
smaller and lighter than power wheelchairs, making it
possible to transport them in cars, maneuver in more
confined spaces, and negotiate curbs and stairs either
independently or with assistance. (11) Manual wheelchair
potentially benefits the wheelchair user's cardiovascular
fitness and upper extremity and trunk muscle strength. (11)
In recent years, however, a significant disadvantage of
these wheelchairs has become evident. Over time,
manual wheelchair propulsion is likely to lead to overuse
injuries and pain in the upper extremities especially in
the shoulders.(10) (11)
The greater risk of overuse injury and repetitive strain
injury has several causative factors. The position of
propulsion (shoulder flexion, abduction and internal
rotation) is also the position of shoulder impingement.(1)
Repetitive use in wheelchair propulsion leads to
inflammation, impingement of soft tissues, muscle tears and
pain. Optimal configuring of the manual wheelchair is
essential to minimize this risk. Long term use of the
manual wheelchair also leads to muscle imbalance,
overdevelopment, strengthening and shortening of the
anterior muscles, deltoid and pecs and weakening and
lengthening of the opposing muscle groups.
Power wheelchairs can provide a means of independent
mobility to people who are unable to propel manual
wheelchairs. They are also used by some individuals who are
capable of propelling manual wheelchairs, but prefer to use
power wheelchairs in order to preserve energy and to avoid
subjecting their upper extremities to damaging forces. (11)
Power wheelchairs, however, have significant disadvantages.
Due to their size and weight, most cannot be transported in
cars or lifted over curbs and stairs. Some power
wheelchairs also require more space for maneuvering, and
thus their use is restricted to environments that have wide
doors and passageways as well as large areas of clear floor
space. (11)
For most individuals the choice between using a power or
manual wheelchair is difficult because both types of
wheelchairs have advantages and disadvantages. A push rimactivated, power-assisted wheelchair which allows manual
wheelchair propulsion with less effort may be a compromise.
(11) The hubs of the Power Assist wheels contain motors
that are activated by force applied to the wheelchair's
push rim. Compared to a standard manual wheelchair, a power
assist wheelchair can be propelled with less force applied
by the person using the wheelchair, reducing the effort
required and possibly reducing the risk of upper extremity
overuse injuries. (11)
One version of the push rim power assist is the e-motion by
Alber. The e-motion power assist is removable from the
wheelchair and so is easily transported. The manual wheel
is interchangeable with the Power Assist wheel and so the
end user can revert to manual if needed.
A recent survey of e-motion end users had interesting
results. The question posed was “How does e-motion
influence the health of it’s users”. The health issues
included shoulder/arm pain, spasticity in arms, back pain,
circulation, respiration, mental health, and well-being in
general. Classifications for each health issue were, “no
trouble yet”, “no effect due to e-motion”, “improvement due
to e-motion’ and “significant improvement due to e-motion.”
The survey was sent to 472 e-motion end users with 102
questionnaires being returned. Some of the results include
significant
improvement
improvement
improvement
significant
improvement
improvement in shoulder/arm pain 26%,
in shoulder/arm pain 22% ; significant
in back pain/postural deformity 17%,
in back pain/postural deformity 26% ;
improvement in well being in general 46%, and
in well being in general 23%.
A recent study comparing the metabolic costs of Power
Assist and manual wheelchair propulsion found that Power
Assist wheelchair propulsion had a lower metabolic cost and
required less mechanical work for the person propelling the
wheelchair, giving evidence that power assist wheelchair
propulsion was less stressful on the upper extremities.(12)
In conclusion Power Assist wheelchairs have a therapeutic
benefit and offer an alternative to manual and power
wheelchairs. With the increase in use in wheelchairs in our
community (13) managing shoulder pain and allowing
individuals to function to their maximum is imperative.
References:
1. Michael L Boninger, Rory A Cooper, Brian T Fay, Alicia M
Koontz, Aaron L Souza,
Shoulder kinematics and kinetics during two speeds of
wheelchair propulsion
Journal of Rehabilitation Research and Development
Washington
Nov/Dec 2002 ;39: 635-650
2. Michael L Boninger, Rory A Cooper ,, Brad E Dicianno,
Michael C Munin ,Jeffrey D Towers,
Shoulder imaging abnormalities in individuals with
paraplegia
Journal of Rehabilitation Research and Development
Washington 2001;38: 401-408
3. Margaret A Finley Randall E Keyser, Kevin J McQuade,
Elizabeth K Rasch, Mary M Rodgers,
Upper-limb fatigue-related joint power shifts in
experienced wheelchair
users and nonwheelchair users
Journal of Rehabilitation Research and Development
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Jan/Feb 2003 ;40: 27-37
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van der Woude,
Mechanical advantage in wheelchair lever propulsion:
Effect on physical
strain and efficency
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comparison of methods to compute the point of force
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S Rao, et al
Electromyographic and kinematic analysis of the shoulder
during four activities
of daily living in men with C6 tetraplegia
Journal of Rehabilitation Research and Development
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,Mary M Rodgers, Pamela J Russell
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Journal of Rehabilitation Research and Development
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10.
K.A. Curtis, Shoulder Pain; Tetraplegic Patients Need
to be Monitored for Pain
TB & Outbreaks Weekly
Atlanta
May 3, 1999 6-7
11. Martha F Somers, Shelby Wlodarczyk
Use of a pushrim-activated, power-assisted wheelchair
enhanced mobility
for an individual with cervical 5/6 tetraplegia
Neurology Report
Alexandria
Mar 2003 ;27 :22
12. Cooper R, Fitzgerald S, Boninger M, et al. Evaluation
of a pushrim-activated,
power-assisted wheelchair. Arch Phys Med Rehabil.
2001;82:702-708.
13. Aging; Demand for wheelchairs to increase 6.9% per year
to 2007
Obesity, Fitness & Wellness Week
Atlanta
Feb 7, 2004
14. (Unpublished) E-motion customer survey