| A Guide to Work Related Upper Limb Disorders (WRULDs) |
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The article also gives general advice regarding the appropriate treatment and management of this condition.
The term WRULD is used here as synonymous with Repetitive Strain Injury, Cumulative Trauma Disorder etc. It is a somewhat vague term under which a large variety of conditions and symptoms are classed. A fundamental distinction can be made between those conditions with a specific recognised medical diagnosis and those of a so-called 'diffuse' nature which still lack a clear-cut diagnosis. Within the first category, the non-diffuse group, the following conditions are frequently encountered:
All these are 'classic' conditions, well recognised, with prescribed clinical tests and clear-cut associated symptoms. This is in contrast to the diffuse group of conditions, which largely escape the clinical tests and sophisticated medical investigation. The factors that are consistent in this group are:
The diffuse group of conditions is characterised by a range of symptoms (ache, pain, tingling, cramps, numbness, heaviness, tightness and others) which tend to vary in location, intensity and nature. It is typical for symptoms to 'jump around' and once established, to appear spontaneously without obvious trigger or cause. Symptoms are often felt 'deep' in the tissues and can be hard to describe by those who experience them. Another aspect can be the emergence of symptoms generally associated with the sympathetic nervous system. Examples include the reporting of heaviness, hands feeling hot or cold, swelling and tightness, usually without any visible signs. In contrast with conditions such as 'tennis elbow' and carpal tunnel syndrome, the structure at fault is not easily identifiable. Difficulties with diagnostic tests and changing symptoms have in the past led some people to believe that this condition is predominantly 'in the mind' rather than reflecting a physical injury. Even though psychological factors do play a role, recent research has clearly identified measurable nerve function deficits.
In spite of the wealth of information and opinions on diffuse WRULD's, the current medical understanding of exactly how this condition is caused, what the damage consists of and how to determine a prognosis, is still very limited. However, 3 groups of risk factors have been identified and are generally accepted as such. These are:
These risk factors are identical for both the diffuse and the non-diffuse conditions. There is anecdotal evidence to suggest that people using the keyboard and mouse are more likely to develop a diffuse condition. Those working in an industrial setting seem to be more likely to develop a more specific form of WRULD. This is likely to be related to the different 'mix' of risk factors in these settings.
Static muscle loading describes muscular activity, which focuses on holding an object or on maintaining a certain posture or position which involves little or no movement. The problem with this form of activity is related to the muscle structure and the way muscles work. For muscles to be able to contract they require energy which is delivered to them via the blood circulation. When muscles contract they effectively compress the blood vessels which feed them and if a contraction is maintained for any length of time, as during static activity, their blood supply is reduced and a build-up of waste products can accumulate. This results in muscle fatigue and can be experienced as an ache or discomfort. Computer work tends to be more static and less varied than clerical or administration work and can cause static muscle loading in a variety of body areas unless regular breaks and changes in activity occur. When using the keyboard, static muscle work is required to hold the arms and hands in place. Furthermore, if the back is not well supported, static muscle activity will occur there and in the muscles of the neck. Over time, this can lead to localised muscle tightness and postural imbalances, which can compromise the blood supply and the nerve function in the arms and hands.
Overuse of specific muscles and repetition of certain activities can carry the risk of straining tissues beyond their normal capacity. Initially fatigue occurs and if demands increase or sufficient changes in activity or breaks are not provided aches, pains and injury can result. Any repetitive task performed continuously without sufficient breaks or changes in activity will place demands on specific structures and result in a risk of injury. The way in which an activity is performed will affect the likelihood of a problem occurring. As an example, we can use the angle of the wrist while typing or using the mouse. With the wrists in a neutral position, the risk of an overuse problem is greatly reduced compared with typing or using the mouse with wrists extended or deviated. This is due to the affected structures working in a neutral, relaxed position, causing minimal compression or stretch and requiring minimal effort and muscle activity.
Stress and other psychological factors, perhaps surprisingly, can play an important part in the onset and experience of WRULD's too. This is due to stress causing increased muscle tension and generally sensitising the nervous system, which leads to an increased perception of pain. Stress factors, whether related to work, family or any other area, can therefore be important contributors to WRULD's. The reason why this condition has been particularly prominent among computer users is probably due to the fact that often all 3 of these risk factors are present in the modern office environment.
Which parts of the body are actually affected and how can the often-varying symptoms be explained? Different structures have been suspected of causing the pains associated with WRULD's and there now is strong evidence that the main site of injury and symptom generation is the nerves rather than muscles, tendons or joints. Although a tendinitis, muscle strain or joint problem may coexist, the real cause of the diffuse pains appears to be located in the nerve structures. A combination of nerve compression, reduced blood supply and over-excitation through the body's stress response is believed to cause a low level inflammation of the nerves. This in turn alters the functioning of these neural structures, generating any of the symptoms listed earlier. As a result, normal touch can cause discomfort and gentle movements can become acutely painful. As the nervous system itself is affected, symptoms can vary greatly. No longer do these nerves simply transmit the information its receptors pick up but they may distort the messages and can even generate their own.
Frequently people with WRULD seek treatment only when the symptoms start to seriously interfere with their work or when their pains persist even during rest. This is unfortunate as early intervention produces the best and fastest results. In our experience the most effective treatment lies in a combination of hands-on techniques, exercises, relaxation, good workstation ergonomics and advice on posture and work pacing. Rest alone does not cure WRULD's, it may at best settle the symptoms temporarily. However, prolonged rest will lead to a deconditioning and weakening of the muscles and associated structures. Before embarking on an exercise regime it is advisable to have an assessment by a physiotherapist who is specialised in the treatment of these disorders to ensure appropriate exercises are given. From an initial assessment the therapist should be able to determine the main underlying contributory factors and develop an appropriate treatment programme for each individual. During the course of treatment, the symptoms experienced by the individual often change. An experienced therapist is able to interpret these changes and to adjust and progress the treatment accordingly. As these disorders take some time to develop, they tend to take time to resolve and often require changes in work pattern and in postural or tension habits. Therefore, treatment can continue over a longer period of time than initially expected. At times, when a person is first assessed, his or her symptoms are quite acute. As the symptoms ease, the treatments are spread out over time with emphasis being placed on self- management. This should allow for new postural and work habits to be formed and a set of exercises to be carried out regularly. There is no standard treatment period: for some people who seek treatment early three or four sessions are sufficient; for others who have developed a more chronic problem treatment may continue for a number of years with appointments at three- or six-monthly intervals. The physiotherapy techniques that have been found to be most effective include:
Exercises are a crucial part of treatment and a specific programme should be developed for each individual to follow. This should include exercises to be used both at home and at work. We often recommend taking up some form of general exercise. This can involve gentle gym workouts, swimming or organised classes. As a rule swimming, yoga, gentle stretch classes and walking are preferable to racquet sports and weight training. People with an established and chronic condition will benefit from a formal work rehabilitation programme, which will progressively increase the tolerance to the critical activity.
Most people with WRULD make a good recovery with appropriate treatment. Some need a long time and some might have to limit or space out particularly straining tasks. Factors that affect the prognosis are:
There may also be underlying postural problems such as a long-standing old back injury or an altered spinal curvature that can affect the prognosis. The work that people are involved in and their ability to manage it, allowing sufficient rest periods or avoidance of specific tasks, will also be of importance as may stress or psychological factors.
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The tip of the iceberg? Attacking WRULDs |
