Repetitive Strain Injury P S Helliwell, W J Taylor
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438 Postgrad Med J: first published as 10.1136/pgmj.2003.012591 on 5 August 2004. Downloaded from REVIEW Repetitive strain injury P S Helliwell, W J Taylor ............................................................................................................................... Postgrad Med J 2004;80:438–443. doi: 10.1136/pgmj.2003.012591 Pain in the forearm is relatively common in the community. ‘‘occupational overuse syndrome’’,4 ‘‘repetitive strain disorder’’, and ‘‘cumulative trauma dis- In the workplace forearm pain is associated with work order’’.5 involving frequent repetition, high forces, and prolonged It is difficult to know sometimes whether abnormal postures. Nevertheless, other factors are these terms refer to specific soft tissue syn- dromes that affect the upper limb (such as carpal involved in the presentation and the continuation of the tunnel syndrome or lateral epicondylitis) as well pain. Notable among these factors are psychosocial issues as to non-specific pain syndromes such as and the workplace environment—the attitude to workers complex regional pain syndrome (also known as reflex sympathetic dystrophy) or fibromyalgia, and their welfare, the physical conditions, and design of or to a ‘‘specific’’ form of non-specific upper limb the job. Primary prevention may be effective but active pain that occurs in occupational settings. The surveillance is important with early intervention and an legal environment has a significant influence upon how these disorders are named. Different active management approach. Physical treatments have jurisdictions have defined the problem differ- not been extensively evaluated. In the established case, ently. In New Zealand, the state owned insurer management should be multidisciplinary, addressing for injuries (Accident Compensation Corpora- tion) has classified ‘‘occupational overuse syn- physical aspects of the job but also addressing the ‘‘yellow, drome’’ into three groups of disorders: localised blue, and black flags’’ which should be viewed as obstacles inflammations, nerve compression syndromes, to recovery. For the worker ‘‘on sick’’ a dialogue should be and pain syndromes. In the UK regulatory established between the worker, the primary care authorities have a prescribed list of compensable disorders—for example, A4: cramp of the hand physician, and the workplace. Return to work should be or forearm due to repetitive movements; A5–7: encouraged and facilitated by medical interventions and beat conditions, mostly bursitis in miners; A8: light duty options. Rehabilitation programmes may be of tenosynovitis; A11: vibration white finger; A12: carpal tunnel syndrome in users of vibrating use in chronic cases. hand tools. ........................................................................... Given the problems with naming these condi- tions, it is not surprising that communication http://pmj.bmj.com/ about them and appropriate research are both difficult. What exactly are we talking about? We fall back on time honoured descriptive meth- THE PROBLEM OF THE NAME ods—the case study. In our practice, the typical ‘‘Repetitive strain injury’’ (RSI) is a poorly case of ‘‘RSI’’ is a female office or production line named condition usually applied to people with worker, conscientious in her job, who develops non-specific upper limb pain in occupational forearm pain after a change in work practice, settings. The name ‘‘transgresses the basic additional demands, or pressure from super- on September 30, 2021 by guest. Protected copyright. principles of taxonomy through the use of terms visors.6 There are few abnormal physical find- which assume or imply findings and causality ings—non-specific tenderness and possibly some that have not been established’’.1 Use of the term impairment of fine movements.3 There may be ‘‘RSI’’ was strongly discouraged by the Royal symptoms of anxiety and anhedonia. Pain Australasian College of Physicians in 1986. generally subsides over the weekend, returning Although the nomenclature has been vigorously quickly while at work. Unless there is a change to debated for nearly 20 years, the existence of the organisation of work and resolution of See end of article for people with upper limb pain in and out of relationship issues, the pain becomes more authors’ affiliations occupational settings is hardly controversial. The troublesome leading to work disability and ....................... problem was nicely articulated by Richard Asher sometimes spread of symptoms to involve the Correspondence to: as long ago as 1957: ‘‘If this condition had some shoulder girdle and neck. Classification criteria Dr Philip Helliwell, reasonable name…then we could profitably for fibromyalgia7 may be met. Musculoskeletal Academic discuss whether it was caused by a neuritis or Patients who present with defined soft tissue Unit, University of Leeds, 36 Clarendon Road, Leeds by costo-clavicular compression or by compres- syndromes such as tenosynovitis or carpal tunnel LS2 9NZ, UK; p.helliwell@ sion of the median nerve in the carpal tunnel…’’. syndrome where the physical findings and inves- leeds.ac.uk Description and case definition of the syndrome tigations confirm the diagnosis, may respond app- without implying causality is a prerequisite for ropriately to physical work task modifications, Submitted adequate clinical investigation into the patho- 19 December 2003 2 Accepted physiology of the disorder. Other labels that Abbreviations: DEA, disability employment advisor; 17 February 2004 have been applied to this condition are ‘‘non- RDS, Regional Disability Service; RSI, repetitive strain ....................... specific work-related upper limb disorder’’,3 injury www.postgradmedj.com Repetitive strain injury 439 Postgrad Med J: first published as 10.1136/pgmj.2003.012591 on 5 August 2004. Downloaded from local injections, or surgery. Such patients are thought to be temporal relationship between a change in work demands distinct from those with ‘‘typical RSI’’, although a recent and the development of pain (for example see Alexander and article has demonstrated a high prevalence of psychological Others v Midland Bank Plc 199918). symptoms in people with carpal tunnel syndrome awaiting The National Institute for Occupational Safety and Health surgery.8 In these cases successful decompression may not review of the epidemiological evidence for work relatedness completely resolve their symptoms. In our view, patients with does not actually include non-specific upper limb pain among upper limb pain who do not have a specific soft tissue the conditions reviewed.19 Many studies that do look at risk syndrome should be diagnosed with an anatomically based exposure and complaints of forearm pain are cross sectional, regional pain disorder—for example, ‘‘non-specific diffuse which creates interpretation problems. In particular, the forearm pain’’.9 ‘‘healthy worker’’ effect cannot be untangled from cross sectional studies. From one of very few population based EPIDEMIOLOGY, CAUSATION, AND ATTRIBUTION longitudinal studies, there appears to be evidence for both physical and psychosocial factors in the aetiopathogenesis of There remain difficulties even with apparently well defined 12 20 soft tissue syndromes as there is little agreement in the forearm pain. The most important risks appeared to be epidemiological literature as to how such syndromes should high levels of psychological distress, repetitive movements of the arm or wrist, monotonous work, and lack of autonomy. It be named or defined.10 This comprehensive review of classi- fication systems for upper limb disorders found 88 different is also noteworthy that a substantial number of people with new onset of forearm pain also meet criteria for chronic disorders and 14 that appeared in more than five of the 27 21 different classification systems examined. There is clearly a widespread pain. Risks of a similar magnitude were found need for consensus upon how upper limb disorders should be in a longitudinal study of newly employed workers, with named and defined. respect to the development of musculoskeletal pain in a number of anatomical sites.22 This study did not measure Upper limb pain (defined by anatomic region) is very physical work exposures but found that psychological factors, common in the general population. By self report, 10% to 20% both workplace related and personal, were associated with of the population have had shoulder pain that lasted more the development of regional pain disorders. than one week in the previous month, 5% to 10% report elbow pain, and 5% to 15% report hand pain.11 About 10% of community UK samples report forearm pain.12 Even more PATHOPHYSIOLOGY (34%) report shoulder pain that lasted more than one day in What are the possible mechanisms by which physical factors the previous month.13 Upper limb pain is associated with may cause pain? Heavy lifting may damage tissue by significant disability in the community: 57% of working age imposing loads which exceed the physical capacity of the adults who reported shoulder pain had reduced working tissue producing muscle or ligament injury. More impor- capacity and 35.5% of them needed help at least occasion- tantly, in terms of prolonged exposures, is the phenomenon ally.14 of creep where collagenous structures lengthen in response to We have already referred to different definitions of ‘‘RSI’’ prolonged submaximal loading. Creep can occur at relatively in different jurisdictions. The major difference between upper low loads and can be accelerated