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ALTHOUGH now much in the news, ‘repetitive strain injury’ is not a new
affliction. The Victorians, for example, talked of all sorts of work-related
syndromes such as ‘upholsterer’s hands’ and ‘fisherwoman’s finger’. But
repetitive overuse, better termed ‘misuse’, can produce symptoms anywhere
in the musculoskeletal system. Cleaners, hairdressers, VDU operators, keyboard
users, butchers, music teachers and machine operators are particularly at
risk of developing problems in their hands, arms and shoulders. My own interest
in these conditions has centred on the study of musicians – and a simple
piece of clinical detective work illustrates several of the problems frequently
encountered in these injuries. The orchestra of a leading touring opera
company was incapacitated when, after an evening performance, many members
of the violin section complained of acute pain and cramp-like stiffness
in their bowing arms. The cause was unknown: local doctors suspected a possible
epidemic of some disease of the muscles and management murmured about an
attack of hysteria that might have spread from desk to desk. The instrumentalists,
however, were convinced their symptoms were genuine.

The problem arose only when they performed a very long Wagner opera
in a particular theatre. The leader of the orchestra provided the most important
clue, suggesting that the angle of the floor in the orchestral pit might
have been a contributory factor. Verdi operas in the same theatre had not
caused symptoms because they are shorter and punctuated by intervals and
pauses for applause. Furthermore, the orchestra had had no trouble after
the Wagner opera in other theatres, which had larger orchestral pits with
gently sloping floors.

So it turned out that the combination of cramped circumstances and a
flat floor at this particular theatre had caused the violinists to strain
their bowing arms and necks as they alternated their glances between music
desk and conductor for almost five hours. When the desks were repositioned
the problem resolved itself and has not occurred since.

This story highlights three important principles in repetitive strain
injury. The first is that symptoms occur only once a certain threshold of
mechanical activity has been exceeded. The second is the enthusiasm with
which doctors suggest alternative but erroneous diagnoses. The third, and
perhaps most serious, is the potential for confrontation between employer
and employee, usually over money. The attraction of studying musicians is
not just that of complementary concert tickets. As a group, musicians are
relatively under-doctored. Unlike professional sporting teams, it is unusual
for an orchestra to have a physiotherapist. And so far few legal battles
over compensation have involved musicians, so case histories are uncluttered
by medicolegal complications.

Different instruments put different areas of the body at most risk.
For keyboard players, the wrists and forearms are most vulnerable, with
both left and right arms affected equally because both hands are used equally,
and the piano stool gives no support for the elbows. Postural problems are
common among flautists, while oboe and clarinet players suffer because they
support the instrument on their thumbs for long periods. Stringed instruments
are the most instructive because of the difference in functions required
of the two arms. The bowing arm is subject to shoulder and upper arm strain.
The other hand, stretched across the finger board, is more susceptible to
finger strain which becomes even more pronounced in players of the classical
guitar, the stringed instrument requiring the maximum stretch. For players
of the cello and particularly the double bass, back problems tend to pre
dominate. Percussionists risk overusing their wrists as they practise their
rolls.

Similar principles apply to other work-related syn dromes. Employees
on pro duction lines, such as elec tronic assembly, are particularly susceptible
to repetitive strain of the hands, arms and shoulders. In sedentary keyboard
operators, the back and fingers are more susceptible to misuse. Low temperatures,
outside work in wet conditions and vibration all seem to exacerbate these
symptoms, probably for various reasons. Activities in the home can also
be relevant. Nursing babies and looking after growing children, for instance,
place strain on the parents’ arm such that subsequent return to the production
line may even provide a welcome respite.

As part of our research on rheumatism, my colleagues and I from the
University of Leeds recently made a study of work in a biscuit-packing factory,
which gives an example of a typical work-place injury. Women work on the
conveyor belts that feed the biscuits from the machine, while the men in
the factory concentrate on mechanical and heavy lifting tasks. A typical
morning working shift of 8 hours is punctuated by 10 minutes for tea, half
an hour for a mid-morning breakfast and 15 minutes for tea. Workers can
also visit the toilet, if they raise a hand to find a replacement on the
line. The lines deliver biscuits 24 hours a day at a constant rate pre-determined
by management. The speed of arm movements required to keep pace resembles
that of energetic breakdancing.

The diversity of injuries workers experience reflects the different
sizes and shapes of the biscuits. Minor variations in weight, as between
‘Finger Nice’, the larger ‘Sports’ and the heavy ‘Bourbon Creams’, become
more pronounced ergonomically when the biscuits are handled constantly for
eight hours. To pick up rows of biscuits and place them in a packing case
requires not only considerable force from both wrists so the column is compressed
together, but also a retaining action from both thumbs stretched at right
angles to the index fingers, so the column does not collapse when in the
air. Understandably, the tendons of the thumb are under considerable repetitive
strain in an unnatural position. Employees develop symptoms of fatigue easily
by the end of the shift and particularly at the end of the week. At first,
this fatigue is relieved by the weekend break but, later, even taking the
four weeks and two days annual holiday in a single block does not help.
For some people, the only abnormal clinical finding is reduced grip strength.
In time, this can lead to the tendon becoming tethered in its sheath (a
true ‘tenosynovitis’) which occasionally requires surgery for relief.

Dangerous biscuits

Different production lines produce comparable problems. ‘Mini Crackers’
destined for airline meals are lighter than conventional ‘Cream Crackers’
but the faster output of a machine making them may tempt management to require
greater repetition. By contrast, the heavier ‘Wheatgerm’ biscuits can be
packed more deliberately, though the resultant packages are heavier and
lifting the sealed packet is more likely to produce elbow and even shoulder
injuries.

A recent review of people referred for compensation for work-related
injuries in Britain found that almost all the women were unmarried, separated,
divorced or had husbands who were themselves invalids. By implication, those
women less dependent upon a working wage may already have left the factory.
Clearly, sociological and ergonomic factors interplay in determining the
course of these work-related syndromes.

It is likely that more than one condition masquerades under the term
‘repetitive strain injury’ and this possibility has fuelled controversy
in the medical literature. In the case of musicians, the term ‘repetitive
strain’ is best reserved specifically for symptoms that are induced by a
particular repetitive technical task but which are relieved by rest and
recur when the technique is repeated. These findings strongly support the
idea that the disorder springs from an initial mechanical strain of muscles
and joints. From this point, opinions diverge. Neurologists, finding little
amiss on clinical examination, have attributed half of the complaints to
‘inflammatory disorder of the tendons’, including tenosynovitis. Rheumatologists,
less convinced that swelling of the joint resulting from such inflammation
is present, have preferred to draw an analogy to writer’s cramp. The persistent
pain that can build up in muscles is also sometimes likened to that caused
by lactic acid accumulating in the muscles of athletes. Probably both contribute
to the symptoms.

Hunter Fry, an Australian orthopaedic surgeon, has recently taken small
samples of muscle tissue from 29 women with the painful chronic overuse
syndrome, as well as from eight volunteers. Women with the overuse syndrome
all showed an increase in Type I fibres and a decrease in Type II fibres,
and an increased number of nuclei and mitochondria in the muscle cells.
No one yet knows quite what these changes mean, and they are different from
those seen in muscles that have atrophied through disuse. Unfortunately,
ethical considerations made it impossible to take samples from the muscles
of people who are performing identical work but have not developed the overuse
syndrome. So we do not know whether people at risk of developing these disorders
start off with abnormal muscles or, indeed, whether the changes arise from
the treatment of the disability.

Doctors have suggested many other factors that might predispose people
to overuse injuries including dominance of one side of the body, giving
an asymmetry in muscle weight (though this does not apply to string players)
and some type of fatigue. Some music students have been found to have laxer
joints than others but such a difference probably accounts for only a fraction
of the problem. Perhaps less plausible, some have suggested that all repetitive
strain syndrome in the arm is referred pain from degenerative joint disease
in the neck. Still others have suggested that hyperventilation, leading
to a rise of levels of carbon dioxide in the blood, may sometimes contribute
to the symptoms.

There is a strong impression that the condition can be made worse by
stress, which suggests that it may be caused by anxiety. But careful interviews
with patients usually reveal the classical history of mechanical strain.
It is hardly surprising that people suffering from this disorder are upset
when their livelihoods are in jeopardy, and so anxiety is probably a secondary
phenomenon.

Some researchers have suggested clinical grading varying from grade
one (pain at one site on activity) through increasing degrees of disability
to grade five (loss of capacity to use because of continuous pain associated
with loss of muscle function). Such grading reveals the not surprising fact
that people are more likely to recover if the symptoms are mild when they
first visit their doctors. A change of technique at work may alleviate symptoms
just as well as stopping the precipitating activity completely. So the term
‘misuse’ is more apt than ‘overuse’, and there may be legal reasons for
preferring this terminology. ‘Overuse’ always implies that liability lies
with the employer, whereas ‘misuse’ could imply fault on the part of the
employee as well.

A few people with such symptoms will have a recognised disease (such
as rheumatoid arthritis) or clear signs of damage (such as compression of
the median nerve in the carpal tunnel at the wrist) caused by repetitive
trauma. Nevertheless, in our clinic, these recognised disorders account
for less than 5 per cent of all people referred with a work-related syndrome.
In the true repetitive strain syndrome, local muscular tenderness and muscle
wasting are common in the late stages, but doctors often find little abnormality
even with a full clinical exam ination.

So the best strategy is to try to identify the precipitating mechanical
factor by exploring the history of the complaint and perhaps by visiting
the workplace. Once the trouble spot has been identified, opinions vary
on whether ‘rest’ should be a simple change in technique or complete abstinence
from movement. Musicians may need to abstain from playing the pieces of
music that bring it on, concentrating on music that is less technically
demanding or written in a different style by another composer. If the troublesome
technique is inherent in most pieces of music, ‘relative rest’ can be tried.
If the symptoms consistently appear after 25 minutes playing, whatever the
style, the musician should practise for no more than 20 minutes at a time
with adequate rest in between. Anyone who needs to practise for four hours
each day should break this into at least four one-hour periods with one
hour’s rest between each and, if this fails to alleviate symptoms, should
try eight periods, each of half an hour. Either of these methods is less
likely to precipitate symptoms than a continuous period of four hours. Similar
principles can be applied to other occupations.

If these simple measures fail, some doctors still favour complete rest,
sometimes immobilising the upper limb in a sling, or even a plaster of Paris
cast. In our experience, the long-term problems of disuse may be more severe
than the symptoms from the misuse syndrome itself and adequate passive and
active physiotherapy should be provided to stop muscles from atrophying.
Someone whose syndrome does have a psychosomatic component will obviously
not benefit from doctors insisting on complete rest.

In 1887 G. V. Poor, describing 21 pianists with symptoms in the hands
and wrists that he attributed to muscular strain, commented that ‘directly
they feel in a small degree better, they fly to the piano’. Many musicians
today still react this way, but they should return to full function gradually,
usually over the course of months rather than weeks or years, and with appropriate
counselling and support.

Workers in factories have less control over their workload. Recently,
repetitive strain syndrome in non-musicians has reached epidemic proportions
in Australia and seems to be increasing in Britain. In Australia, people
have an obvious financial incentive in establishing the diagnosis because
they get lump sum payments for such work-related diseases. The resultant
court cases, spearheaded by trade unions are estimated to have cost the
Australian government more than Pounds sterling 500 000. Because most of
the patients allowed damages do not have signs of inflammation or injury,
the Royal Australasian College of Physicians has recommended using the alternative
term ‘regional pain syndrome’.

In Britain, the Institute of Occupational Medicine at Edinburgh has
published work identifying occupations with a relatively high risk of symptoms
arising from repetitive movements. The Repetitive Strain Injury Association,
a self-help group for patients, has now been established in Middlesex. Psychological
and social factors are likely to contribute increasingly to this contentious
physiological concept.

Dr Howard Bird is Senior Lecturer in Rheumatology at the University
of Leeds and Honorary Consultant Rheumatologist at the General Infirmary
at Leeds and the Royal Bath Hospital, Harrogate.

Further information is available from the RSI Association, Communicare,
Christchurch, Redfordway, Uxbridge, Middlesex UB8 1S2.