New guidance for the diagnosis of work-related arm pain, sponsored by the Health and Safety Executive and published this month, could make it easier to identify people who are suffering from repetitive strain injury (RSI).
Muscular disorders, including RSI, are by far the most commonly reported work-related illnesses, according to a survey published by HSE last month, so the NHS can expect many cases among its own workforce. A total of 1.2 million people are affected, and the numbers are rising.
The new classification endeavours to abolish RSI as an umbrella term and replace it with a series of well defined disorders with specific diagnostic criteria.
1It was drawn up at a consensus conference last year involving rheumatologists, orthopaedic surgeons, occupational health staff and physiotherapists.
The aim is to encourage doctors to put a diagnosis on the signs and symptoms patients present with, before trying to link these to hazards at work.
'There has been a tendency to say something is work related before making the diagnosis. We are proposing that the diagnosis should come first and the attribution should come afterwards, ' says Professor Michael Harrington from the Institute for Occupational Health at Birmingham University, and co-author of the new guidance.
Out of the consensus has come a series of six well-defined clinical conditions affecting the arm, including carpal tunnel syndrome, tenosynovitis of the wrist, and shoulder capsulitis, which can be diagnosed from signs and symptoms. What then remains is a condition that the panel has labelled 'pain in the forearm in the absence of specific diagnosis or pathology'.
'Most painful arm conditions can be diagnosed. We are suggesting that people use the criteria to diagnose these conditions and then look to see if there are any work-related factors. We feel that further research is needed on diffuse pain in the forearm with no apparent signs or positive test results, ' says Professor Harrington.
A new test, measuring sensitivity to vibrations, can also help in the diagnosis of RSI patients (see box 1).
2'This research is certainly very promising. It suggests there is a lesion which is neurological rather than musculoskeletal which may account for diffuse pain in the forearm that doesn't go away with rest, ' Professor Harrington explains. The idea that repeatedly performing a particular movement, whether for work or play, can lead to muscle pain should come as no surprise. But, with rest, a musculoskeletal injury should get better and the pain should go away. In the case of RSI, there is frequently no evidence of muscle or joint damage and the pain does not disappear even when the patient stops the troublesome movement.
This is why there has been a tendency to blame RSI on psychological problems and why sufferers have had such a hard time getting anyone to take them seriously (see box 2).
The judicial system has started to take a more sympathetic approach, with at least 17 well-known cases getting significant awards of compensation, and others obtaining less highly publicised out-of-court settlements. Such successes are encouraging more people to pursue claims.
Tom Jones, a personal injury lawyer with Thompsons - a law firm which usually has around 1,000 RSI claims on its books - discerns two clear phases in the modern history of RSI. During the first phase in the mid and late 1980s medical testimony was challenged in the courts and judges took a negative view of RSI.
But, in the second wave, since around 1993, cases have been looked at much more carefully and compensation has been awarded where employers have been seen to be careless of their employees' welfare.
According to the results of HSE surveys, there are probably about 120,000 new cases of RSI per year. Across the European Union, a survey recently uncovered 17 per cent of people complaining of RSI, with a slightly lower figure of 11 per cent in the UK. Typical symptoms include numbness or tingling in the arm or hand, aches and pains in the muscles, joints or soft tissues, or loss of strength and grip in the hand.
In the US, RSI accounts for 60 per cent of all reported industrial illness (see box 3).
In the early stages, symptoms only come on when the triggering activity is performed. But, as the condition worsens, symptoms start earlier in the day, even before work, and may continue into the night, leading to sleep disturbance. In the most advanced cases, sufferers are in almost continuous pain and even the smallest arm actions, such as lifting or moving household items, are difficult. This can take months or years to improve, or may be permanent. RSI can arise or be made worse by working practices that require repeated, often awkward movements, especially if this involves applying pressure. Bad workplace design, poor siting of equipment and inadequate rest periods are common factors in cases of RSI.
Tenosynovitis, writer's cramp and beat hand, elbow or knee are all classified as industrial diseases for which social security benefits are paid to sufferers who are assessed to be at least 14 per cent disabled. Carpal tunnel syndrome is also ranked as an industrial disease when it can be shown to be caused by use of vibrating equipment.
A number of organisations, including the HSE, the London Hazards Centre, Unison and the RSI Association produce information packs about RSI prevention and awareness. Employers must, by law, assess the safety of the work carried out by their employees - and that should include ergonomic evaluations to minimise the risk of RSI. But Peter Kilbride, director of the RSI Association, believes there is a significant gap between good practice and working practice.
'Assessments are often done by line managers who are not qualified to carry them out and, even when employees are advised about taking breaks to reduce the risk of RSI, there is great pressure on them from their superiors simply to get the work done, ' he explains.
Most cases of RSI are settled out of court, but are not limited to computer keyboard operators. Compensation has been awarded to electronics production line workers, figurine painters and poultry pluckers. An industrial radiographer and hospital domestic staff using polishing and buffing machines have also been recorded as suffering from RSI.
REFERENCES
1 Harrington J, Carter J, Birrell L et al . Surveillance case definitions for workrelated upper limb pain syndromes. Occup Environ Med 1998; 55(4): 26471.
2 Greening J, Lynn B. Vibration sense in the upper limb in patients with repetitive strain injury and a group of at-risk office workers. Int Arch Occup Environ Health 1998; 71: 29-34.
Box 3. US and them
One of the growing causes of occupational illness in the US has been RSI (occasionally referred to as cumulative trauma disorders [CTD]) and particularly from a subset of this condition, carpal tunnel syndrome (CTS).
There is a long history of these disorders following the development of new technologies.
Allard Dembe, in his recent book Occupation and Disease (Yale, 1996), traces CTS back to writer's cramp in the 1830s with the development of a large scale clerical workforce, to telegraphists' cramp in the later 1800s with the emergence of telegraphic communications, and finally to the growth of the computer industry in the late 20th century.
Between 1983 and 1993 in the US, CTDs grew more than 10-fold and now account for 60 per cent of all occupational illness reported in the US. Dembe reports that the cost for the average CTD case is $8,070 in medical bills, lost wages, and rehabilitation expenses, which is almost twice the cost for all other workers' compensation claims. If surgery is required, the cost for a CTD case is almost $30,000.
It has recently been estimated that the incidence of CTS is between 400,000 and 500,000 cases per year in the US, with economic costs in excess of $2bn per year.
About 332,000 'repeated trauma' cases were reported by the Bureau of Labor Statistics in 1994, an incidence rate of 0.41 per 100 full-time workers, and an increase of 79 per cent in only four years.
The 41,019 cases of occupational carpal tunnel syndrome (OCTS) represented 11.75 per cent of all work-related illnesses reported to the BLS in 1993. Studies in Washington and Wisconsin also demonstrated increasing OCTS compensation claim incidence.
A recent study from Manitoba, Canada, found that repetitive strain injuries were the subject of 9.3 per cent of all workers' compensation claims received in 1991.
Tendonitis and CTS were the most frequent diagnoses.
It should be noted that CTS is only one dimension of RSI and it is extremely difficult to prove that it was caused by work.
Thus the lower number of workers' compensation cases and claims may be more a reflection of the desire to shift the cost away from the employer to the employee rather than a statement that most of the cases are not work-related.
In the US, when an employee goes to a doctor for medical treatment, they will be asked if the injury is work-related. If the employee answers that it is, the doctor will generally not treat the patient until the Workers' Compensation Board has ruled on the claim. Health Insurers will not honour a claim if the employee has indicated that it is work-related.
Since employers are interested in keeping their workers' compensation taxes down they tend to challenge most of the cases, leading to a situation known as controversion.
Generally, until the responsibility for the case is resolved, no medical treatment is rendered. The impact of this delay in treatment is quite serious.
In a 1975 national study of occupational disease cases ultimately decided in the claimants' favour, the average period between the start of lost time and the first payment was one year.
In a study at the Mount Sinai Medical Center in New York, for 38 cases of CTS which were judged to be work-related, the time between the date on which the case was indexed by the Workers' Compensation Board and the date of the ruling averaged 15.6 months (range 2.8-52.2 months).
These delays in treatment may cause CTS patients to deteriorate and become unnecessarily disabled. A recent study from the Washington State workers' compensation system showed that the duration of disability before surgery is an important predictor of duration of disability after surgery.
The growth of RSI, and especially CTS, in the US has led to advances in ergonomic designs of computer equipment (as in better designs for the mouse and the keyboard) and the growth of adjunct equipment like wrist pads, but not much has happened in other industries, including construction and garment production.
While many states are experimenting with managed care approaches to workers' compensation programmes, none has effectively dealt with the issue of delay in treatment. The implication is that we will continue to see both cases and costs rise for these injuries.
Howard Berliner is associate professor and chair, health services management and policy, New School for Social Research, New York.
Box 2. 'My life was totally destroyed'
As builders installed Anne Packer's new kitchen last month they had to allow for the fact that she cannot raise her right arm properly - a legacy of the RSI she acquired while working for North East Thames regional health authority. Now registered 20 per cent disabled, she recently received a£70,000 out-of-court settlement from the region for the damage to her arm, following a three-year fight for compensation backed by Unison.
'I really reached rock bottom. My life was totally destroyed because I couldn't work or do the things I enjoyed, like gardening, bowling and badminton, and they seemed to be making out that I was a liar, ' Ms Packer recalls.
While she received her disability benefit from social security, the NHS would not recognise her injury.
'There was nothing to show on the x-rays or MRI scan, so the NHS doctors wouldn't diagnose repetitive strain injury, ' she says.
It was only after one of the country's leading rheumatologists confirmed RSI, that the offer of compensation was made.
A senior buyer of hospital supplies, Ms Packer worked for the NHS for 10 years and the injury arose over a six-month period after an office move she found unsatisfactory.
'I was stuck at a pedestal desk, with a computer on either side of me, a printer on the filing cabinet and a walkway behind me. I was working either to the left or right or on my knee, ' she says.
Requests for support rollers to go under her arms went unanswered, and pains in her fingers gradually moved up her right arm and into her shoulder and neck.
Each day in the office began with a dose of painkillers. In May 1994, Ms Packer was signed off sick and her employment was finally terminated after 18 months of sick leave. It took nearly two years to get the NHS to agree to grant her pension rights, and this was quickly followed by the compensation payment.
'I am 56, but I hadn't planned to retire early. I was getting remarried and I wanted to be able to go on working so that we could extend and modernise our house. All that had to change, ' she says. Ms Packer's difficulties in getting compensation for her RSI stem from the fact that there were no visible signs of her condition. Claims are much harder to win when there is nothing to see.
Box 1. Feeling the effects
People who complain of diffuse pain in the arm, with no apparent physiological abnormalities, may have measurable signs of nerve damage. Clear changes in vibration threshold have been detected in the median nerve of the arm in office workers who spend a lot of time at computer keyboards.
In a two-year study at University College, London, neurophysiologist Bruce Lynn and physiotherapist Jane Greening used a vibrametre to measure the vibration threshold in three groups of people - 29 office workers, three of whom were currently experiencing arm pain, 17 patients, all of whom had arm pain, and 27 pain-free controls.
They found that RSI sufferers had reduced sensitivity in the area of the hand supplied by the median and ulnar nerves. They felt normal pressure in this area as pain, indicating nerve damage.
The researchers proposed that vibration tests could be used not only to assess patients with diffuse arm pain, but also to test people who spent a lot of time using computer keyboards. That way, those at risk of nerve damage could be detected and their working conditions changed before they started to get symptoms.
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