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Occupational disorders in the locomotor system—Myth or reality?
Occupational Disorders in the Locomotor System-Myth or Reality?
I. Goldie
The Overall Problem
after some time recurs, and a question arises as to whether the recurring symptoms are a true recurrence of the original occupational disorder the beneficiary receives 100% compensation; this continues throughout the time the investigation is pursued to determine whether the recurrence is directly connected with the original disorder or is an entirely new appearance of symptoms without correlation to the initial complaints. It is not uncommon that such investigations can take 5-6 years with an average time of 2 years. The medical profession has been faced with a dilemma. Despite the numerous publications on the influence of load on the locomotor system there is still an enigma; why do so many people withstand the strain of heavy workloads without locomotor symptoms whereas others cannot? In view of this the difficulties become evident for the medical profession who have to comply with the insurance jurisdiction which expects that physicians should be able to pass judgement on the injurious effects of work on the human frame. It has become a fictitious demand. The context of the law is such that if a doctor is uncertain or if doctors have conflicting views on the origin of an occupational disorder the insured individual (and all people at work are insured by the National Health Insurance system) should not suffer economically by this. Instead it is the insurance that should carry the expenses and hence the beneficiary receives his full compensation. No doubt doctors have been wondering for a long time what their contribution to the solution of problems connected with work-related ailments may be as the law allows this sidestepping of medical opinion. Another problem the medical profession has to face is to pass an opinion on the relationship of chronic symptoms, i.e., chronic disability, to the original cause
It is not uncommon that a doctor after a day’s gardening will complain of pain and discomfort in his back and shoulders. Quite logically he will ascribe his condition to the physical exertion. On meeting a labourer complaining of locomotor pain related to load experienced at work the same doctor may not be as ready to accept the relationship of work to discomfort. The reason for this is simple and can be looked at in two ways. The first problem is that from a medical point of view difficulties arise in finding evidence that standardised workloads necessarily result in bodily harm. The second problem is the uncertainty created if the proposed occupational pain and/or discomfort be not only a scapegoat but could be related to the possibility of receiving workmen’s compensation which in certain regions is very generous. The latter possibility is of course a very sensitive issue-almost on the verge of an accusation-but evidence is accumulating to prove the assumption not to be totally incorrect. On 1 July 1977 a law was introduced in Sweden the object of which was to guarantee 100°? compensation to any worker who claimed that pain, discomfort, distress or disability was related to work. The reason for this law at its introduction was to put pressure on employers to improve the work environment. After 13 years’ experience the question arises as to whether the aim has been achieved. The answer is-no. Instead the law has eventually enabled a source of good income. In other words as long as an absence lasts because of occupational disorder the beneficiary receives his/her full wage. If the disorder heals but
Ian Goldie, Department Stockholm, Sweden. Current Orthopaedics 0 1991 Langman
of Orthopaedics,
Karolinska
Hospital,
(1991) 5.202-205
Group UK
Ltd
202
OCCUPATIONAL
of disorder based on occupational inadequacies. This indeed offers great difficulties as the law demands what is called ‘reversed evidence’. This means that if stronger objections cannot be raised against a relationship between residual symptoms and the original occupational disorder the residual permanent disability is regarded as a result of the occupation. In other words, if a shoulder or back ailment has been accepted as an occupational disorder and the insured insists that a residual pain after 1, 2 or more years has its origin in the occupational behaviour this will be accepted-with all the economic consequences this involves-unless the doctor can put forward stronger arguments against the beneficiary’s claims; this is not an easy task which explains partially the enormous increase in occupational insurance claims. Thus, in 1981 65% of occupational insurance claims were accepted with an increase in 1987 to 87% acceptance rate, The number of claims increased from 42000 in 1981 to 100000 in 1987. In 1987 the insurance cost for occupational disorders totalled 4.6 billion Swedish Crowns (Sw.Cr) (&l = 10.30 Sw.Cr) a sum which is covered by employer dues. In December of 1988 the insurance fund ran out of money and for the coming year an additional billion was expected for coverage to be defrayed by the employers who had their 0.9% outlay of budget increased to 2.357:. The heavy working population is mostly affected by occupational disorders; these include lumberjacks, builders, railway-roadworkers, miners, slaughterers-”
The Back as a Special Problem Of a total of 122012 occupational disorders 24636 were due to overload and among those back disabilities had a leading position with 11032, followed in frequency by the shoulder and arm in 5533, the neck in 2138 and hip in 23 19. The back has of course always been an accepted target for overload creating discomfort and pain. If a heavy object is lifted at some distance from the axis upon which the moment acts then the force is considerable and many believe that lumbar pain may arise as a result of loading-or overloading-the back particularly in bending. The position of the back and also its posture causes great variations in the pressures registered in the intervertebral discs. Biomechanical thinking has therefore prompted a number of orthopaedists and ergonomists to make recommendations for the evaluation of occupational disorders of the back based on position at work, the handling of materials and loads, and the movements expressed during work. Lifting loads of 10 kgs (6 kgs for women) with a comfortable work position or lifting 20 kgs (12 kgs for women) near the body are not regarded as occupational hazards. Any weight exceeding this irrespective of distance from load to body is regarded as a possible cause for development of a disorder of some kind. The risk of occupational disorder increases according to the position of the
DISORDERS
IN THE
LOCOMOTOR
SYSTEM
203
back, e.g., if this is bent forward, twisted or both. Factors to be further considered are the weight, form, consistency, speed by which the lift is performed, distance of lift and time of exposure. Vibrations are ascribed some importance. With this as a background it is understandable that people seldom nowadays ‘experience backache’instead they ‘injure their backs’. The task causality is obvious to the backpain sufferer. The employer culpability is equally obvious as it is the improper work environment which initiates all the problems. The doctor who will not always accept the proposed relationships between work and pain and who challanges the validity of the sufferer’s complaint can easily be replaced by someone else who will have no scruples in certifying the relationship. There is some truth in the statement by Awerbuch that: ‘Abnormal diagnosis behaviour leads to abnormal illness behaviour in the patient and is invariably compounded by abnormal treatment behaviour’. This has its reflection on economy. Disease has direct and indirect costs. The former costs which amount to 307; are those involved in the actual care of disease. The latter amount to 70% cover the consequences of disease-disability compensation and early retirement due to failing health. The proportions are quite different in back pain--more than 950,/, of the costs fall outside the immediate medical care. In 1989 the total cost covered by the Swedish Society for Back Pain amounted to 24.3 billion Sw.Cr. Of this large sum occupational back pain was responsible for six,. individual factors two and unsatisfactory treatment four billions (Table 1).
Table l&Dlrect causes.
and indirect
costs of back pain based on different --_ 1989 Million SW. Crowns (fl = 10.30Sw.Cr) -__--_
Work environment Physical Psychogenic Indlcidual
2000 4000
factors
Unsatisfactory
methods
2000 of treatment
4000 --~_
Jonsson
1990.
The reasons for inability to work due to back pain have been calculated;’ no more than lo”,; of back pain could be found to originate from physical strain in various occupations. Psycho-social factors had a great impact (207:) in those experiencing back pain as also did insurance benefits which ran up to 40% (Table 2). The overall amount of sick-leave doubled when compensation was increased from SOS; to 80% of income; when considering back pain in increase was six times more. If the problems of back pain can be handled satisfactorily it is suggested that society will benefit
204
CURRENT
ORTHOPAEDICS-ANNOTATION
Table 2-The relative importance work because of back pain.
of various
factors
on inability
Work environment: Physical : heavy lifts, locked positions Psychological,
satisfactory
10%
comradeship
Individual factors: smoking, lifestyle etc. Bad medical
20% 10%
management
20%
Insurancebenefits Nachemson
to
40%
1990.
economically by 3 billion SEK per annum (Table 3). How can this goal be reached? An active attitude is required in the patient with back pain. Education is important. Let the patient know everything about backache-knowledge of its etiology and reassurance that back pain need not lead to life long disability. That pain on movement, and also on loading the back is not harmful. There is no danger in returning to work despite some pain in the back this will not necessarily predispose a recurrence. In other words information, instruction, insight and incessant-but still modulated-activity will lead to the incarnation of a healthy back. The proof of the success of these five i’s is well demonstrated in the good results obtained in back schools, and reported in epidemiologic studies and scientific assays of environment and work.
Table 3-Calculation disorders.
of benefit for Society with better care of back
1989 Million SW. Crowns (fl= 10.30 SW. Cr) Decreased
compensation
Decreased
early retirement
Increased
running
costs
Net profit for Society Jonsson
time
2700 700 150 3250
1990.
Neck and Shoulder Problems (and R.S.I.) Over the last few years greater attention has been paid to the neck-shoulder problem.10v l l The shoulder is connected with the trunk by one joint only-the sternoclavicular joint. Stability is maintained by the massive muscles which form one large complex combining the neck with the shoulder. It is thus not surprising that d’isorders of the neck can involve the shoulder and vice versa. Work involving the upper extremity in an abducted and/or flexed position will undoubtedly engage the neck without the head necessarily being moved or placed in any particular position. If this is the case it is suggested that the strain on the neck muscles will be further increased-
a strain which will be more pronounced if a work protection helmet is worn. There are certain groups who run a higher risk of occupational or load disorders. These are among men slaughterers, butchers, food store workers, painters and mechanics. Among women, mechanics, truck and crane drivers, butchers, seamstresses, dentists and computer operators appear to run the highest risks of neck shoulder disorders. It has been claimed that intervertebral disc degeneration may increase when excessive load is exerted on the cervical spine and that pain may result. This may be partly true as disc degeneration has been found to be 4-5 times more prevalent in dentists and miners than in the general population. The reason for this is thought to be excess neck loading. There are only weak correlations between radiographic disc degeneration and pain, discomfort and disability. It has been shown that for asymptomatic individuals the preparation with and without cervical disc degeneration is very much the same. Further, occupational stress from heavy jobs does not seem to be an important etiologic factor for degenerative cervical disc disease despite what has been said above. There is a problem called tension neck appearing in computer workers and in females working in heavy industry. The cause and pathology of this is not known and the diagnosis is made for an individual who in suffering discomfort in the neck, ascribes this to work and the doctor is at a loss to make a more specific diagnosis. The same can be said about a condition called OCD, occupational cervico-brachial disorder. It is met with in office clerks and computer workers who ascribe their discomfort to working conditions. Experts have tried to give a scientific explanation for the condition but failed. Instead a hypothesis is presented combining numerous factors believed, surmised, proposed, or suggested to serve as causative. The central point of interest is static load over time which is presumed to cause injury leading to pain, tiredness and local tenderness. The response to the static load is influenced by physical stress, concentration, lack of pauses, a ‘locked’ working position, too high a working speed and other factors. In summary the problems arise from physical load, mental stress, work organisation, personality and life style. All this reflects an attitude which has prevailed in Australia under the expression of ‘repetition strain injury’ (RSI). With time strong criticism has been raised and it has been suggested ‘. . . that medicine has become a disabling profession turning citizens into patients to be saved by the experts. The ‘RSI’ experience bears our the dangers of an expansionist profession, which transforms ‘ills’ into ‘illness’ to be treated by doctors until persons lose their ability to cope with indisposition or even with discomfort’; strong words but thoughtworthy. As for the neck and upper extremity it may not be too bold to conclude that the pathophysiology of use-
OCCUPATIONAL
associated symptoms
discomfort is indeterminate and that the complex defies current nosology.
DISORDERS
IN THE
LOCOMOTOR
SYSTEM
205
and knee. A study of this kind prompts further investigations in particular to identify specific exposure risks.
Osteoarthritis Finally, a problem of some concern is osteoarthritis. Can this be caused by heavy physical load on the weight bearing joints? Is deterioration of osteoarthrosis an age dependent process per se or does physical load increase the rate of degeneration? And symptoms--do they become aggravated by physical load? The medical answer is a slightly wavering no to all these questions. It is too well known that many people with advanced degenerative disease carry on their daily activities, including heavy work, without any discomfort. As long as this is a fact it will be difficult for many doctors to accept workload as a cause of both degeneration and symptoms. Some epidemiologic studies nevertheless support the assumption that heavy physical work load may contribute to osteoarthritis of both hip and knee. A study has been performed to seek any relationship between certain occupations with high physical workload and the development of severe osteoarthrotic changes in the hip and knee joint resulting in the need for hospital care. The population studies consisted of 5 15 174 persons from a census of 1980. The people held the same occupation in 1980 as they did in the censuses of 1960 and 1970. The study population was followed concerning hospital care for osteoarthrosis of the hip and knee during 1981 to 1983 by linkage to a Hospital Discharge Register. Different blue collar occupations were classified as being at high or low risk to major forces acting on the hip and knee; outcomes were compared. Male farmers. construction workers, firefighters and some processing workers had an excess risk of hospitalisation due to osteoarthritis of the hip and of the knee joint. Female postmen had an excess risk of osteoarthritis of the hip and female cleaners of the knee joint. The hypothesis was supported that heavy physical workload contributed to osteoarthrosis of both hip
Conclusions Despite the attempt to blame load factors for contributing to work incapacity questions can still be pertinently asked: how much work can disable an individual to the extent that work becomes impossible? It is not an uncommon finding that despite work being continual the alleged harmful effects cease. It seems that in the present sociopolitical climate that medical questions can be ignored or manipulated. In view of this the Swedish Orthopaedic Society has stated that medical experts need not be consultants. Are occupational disorders in the locomotor system myth or reality? If the ‘hypothetical realities’ of today can materialise in a scientifically acceptable manner the myth will vanish by tomorrow.
References I. Nachemson 2.
3. 4.
5. 6. 7. X. 9.
10. 1 I.
A. Work for All. For those with Low Back Pain As Well. Clin. Orthop 1983; 179: 77-85. Nachemson A. Ont i ryggen: Ryggproblemets omfattning. p. 1622. Prevention infiir framtiden. p. 78 82. Rapport fran SBU, Stockholm 1990. Kelsey J L. Epidemiology of musculoskeletal disorders. Oxford University Press, New York, 1982. Kelsey J. et al. An epidemiologic study of lifting and twisting on the job and risk for acute prolapsed lumbar intervertebral disc. J Orth Res 1984; 2: 61-66 Frymoyer J W, Rosen J C. Clements J. Psychologic factors m low-back-pain disability. Clin Orthop 1985; 195 : 178-l 84 Frymoyer J W, Mooney V. Occupational Orthopaedics. J Bone Joint Surg 1986: 68A: 469474 Pope M, Frymoyer J, Andersson G. Occupational low back pain. Praeger, New York, Greenwood Press Inc. 1984 Pope M. Impact and vibration and their effects on the lumbar spine. Thesis. University of Gothenburg, 1990 Schultz A. Andersson G, &tengren R, Haderspeck K, Nachemson A. Loads on the Lumbar Spine. J Bone Joint Surg 1987; 64A: 713-720 Troup J D G. Martin J W, Lloyd D C E F. Back Pain in Industry. Spine 1981; 6/l : 61-69 Videman T, Nurminen T, Tola S, Kuorinka I. Vanharanta H, Troup J D G. Low-Back Pain in nurses and some loading Factors of Work. Spine 1984; 9/4: 400-404
I. Goldie
The Overall Problem
after some time recurs, and a question arises as to whether the recurring symptoms are a true recurrence of the original occupational disorder the beneficiary receives 100% compensation; this continues throughout the time the investigation is pursued to determine whether the recurrence is directly connected with the original disorder or is an entirely new appearance of symptoms without correlation to the initial complaints. It is not uncommon that such investigations can take 5-6 years with an average time of 2 years. The medical profession has been faced with a dilemma. Despite the numerous publications on the influence of load on the locomotor system there is still an enigma; why do so many people withstand the strain of heavy workloads without locomotor symptoms whereas others cannot? In view of this the difficulties become evident for the medical profession who have to comply with the insurance jurisdiction which expects that physicians should be able to pass judgement on the injurious effects of work on the human frame. It has become a fictitious demand. The context of the law is such that if a doctor is uncertain or if doctors have conflicting views on the origin of an occupational disorder the insured individual (and all people at work are insured by the National Health Insurance system) should not suffer economically by this. Instead it is the insurance that should carry the expenses and hence the beneficiary receives his full compensation. No doubt doctors have been wondering for a long time what their contribution to the solution of problems connected with work-related ailments may be as the law allows this sidestepping of medical opinion. Another problem the medical profession has to face is to pass an opinion on the relationship of chronic symptoms, i.e., chronic disability, to the original cause
It is not uncommon that a doctor after a day’s gardening will complain of pain and discomfort in his back and shoulders. Quite logically he will ascribe his condition to the physical exertion. On meeting a labourer complaining of locomotor pain related to load experienced at work the same doctor may not be as ready to accept the relationship of work to discomfort. The reason for this is simple and can be looked at in two ways. The first problem is that from a medical point of view difficulties arise in finding evidence that standardised workloads necessarily result in bodily harm. The second problem is the uncertainty created if the proposed occupational pain and/or discomfort be not only a scapegoat but could be related to the possibility of receiving workmen’s compensation which in certain regions is very generous. The latter possibility is of course a very sensitive issue-almost on the verge of an accusation-but evidence is accumulating to prove the assumption not to be totally incorrect. On 1 July 1977 a law was introduced in Sweden the object of which was to guarantee 100°? compensation to any worker who claimed that pain, discomfort, distress or disability was related to work. The reason for this law at its introduction was to put pressure on employers to improve the work environment. After 13 years’ experience the question arises as to whether the aim has been achieved. The answer is-no. Instead the law has eventually enabled a source of good income. In other words as long as an absence lasts because of occupational disorder the beneficiary receives his/her full wage. If the disorder heals but
Ian Goldie, Department Stockholm, Sweden. Current Orthopaedics 0 1991 Langman
of Orthopaedics,
Karolinska
Hospital,
(1991) 5.202-205
Group UK
Ltd
202
OCCUPATIONAL
of disorder based on occupational inadequacies. This indeed offers great difficulties as the law demands what is called ‘reversed evidence’. This means that if stronger objections cannot be raised against a relationship between residual symptoms and the original occupational disorder the residual permanent disability is regarded as a result of the occupation. In other words, if a shoulder or back ailment has been accepted as an occupational disorder and the insured insists that a residual pain after 1, 2 or more years has its origin in the occupational behaviour this will be accepted-with all the economic consequences this involves-unless the doctor can put forward stronger arguments against the beneficiary’s claims; this is not an easy task which explains partially the enormous increase in occupational insurance claims. Thus, in 1981 65% of occupational insurance claims were accepted with an increase in 1987 to 87% acceptance rate, The number of claims increased from 42000 in 1981 to 100000 in 1987. In 1987 the insurance cost for occupational disorders totalled 4.6 billion Swedish Crowns (Sw.Cr) (&l = 10.30 Sw.Cr) a sum which is covered by employer dues. In December of 1988 the insurance fund ran out of money and for the coming year an additional billion was expected for coverage to be defrayed by the employers who had their 0.9% outlay of budget increased to 2.357:. The heavy working population is mostly affected by occupational disorders; these include lumberjacks, builders, railway-roadworkers, miners, slaughterers-”
The Back as a Special Problem Of a total of 122012 occupational disorders 24636 were due to overload and among those back disabilities had a leading position with 11032, followed in frequency by the shoulder and arm in 5533, the neck in 2138 and hip in 23 19. The back has of course always been an accepted target for overload creating discomfort and pain. If a heavy object is lifted at some distance from the axis upon which the moment acts then the force is considerable and many believe that lumbar pain may arise as a result of loading-or overloading-the back particularly in bending. The position of the back and also its posture causes great variations in the pressures registered in the intervertebral discs. Biomechanical thinking has therefore prompted a number of orthopaedists and ergonomists to make recommendations for the evaluation of occupational disorders of the back based on position at work, the handling of materials and loads, and the movements expressed during work. Lifting loads of 10 kgs (6 kgs for women) with a comfortable work position or lifting 20 kgs (12 kgs for women) near the body are not regarded as occupational hazards. Any weight exceeding this irrespective of distance from load to body is regarded as a possible cause for development of a disorder of some kind. The risk of occupational disorder increases according to the position of the
DISORDERS
IN THE
LOCOMOTOR
SYSTEM
203
back, e.g., if this is bent forward, twisted or both. Factors to be further considered are the weight, form, consistency, speed by which the lift is performed, distance of lift and time of exposure. Vibrations are ascribed some importance. With this as a background it is understandable that people seldom nowadays ‘experience backache’instead they ‘injure their backs’. The task causality is obvious to the backpain sufferer. The employer culpability is equally obvious as it is the improper work environment which initiates all the problems. The doctor who will not always accept the proposed relationships between work and pain and who challanges the validity of the sufferer’s complaint can easily be replaced by someone else who will have no scruples in certifying the relationship. There is some truth in the statement by Awerbuch that: ‘Abnormal diagnosis behaviour leads to abnormal illness behaviour in the patient and is invariably compounded by abnormal treatment behaviour’. This has its reflection on economy. Disease has direct and indirect costs. The former costs which amount to 307; are those involved in the actual care of disease. The latter amount to 70% cover the consequences of disease-disability compensation and early retirement due to failing health. The proportions are quite different in back pain--more than 950,/, of the costs fall outside the immediate medical care. In 1989 the total cost covered by the Swedish Society for Back Pain amounted to 24.3 billion Sw.Cr. Of this large sum occupational back pain was responsible for six,. individual factors two and unsatisfactory treatment four billions (Table 1).
Table l&Dlrect causes.
and indirect
costs of back pain based on different --_ 1989 Million SW. Crowns (fl = 10.30Sw.Cr) -__--_
Work environment Physical Psychogenic Indlcidual
2000 4000
factors
Unsatisfactory
methods
2000 of treatment
4000 --~_
Jonsson
1990.
The reasons for inability to work due to back pain have been calculated;’ no more than lo”,; of back pain could be found to originate from physical strain in various occupations. Psycho-social factors had a great impact (207:) in those experiencing back pain as also did insurance benefits which ran up to 40% (Table 2). The overall amount of sick-leave doubled when compensation was increased from SOS; to 80% of income; when considering back pain in increase was six times more. If the problems of back pain can be handled satisfactorily it is suggested that society will benefit
204
CURRENT
ORTHOPAEDICS-ANNOTATION
Table 2-The relative importance work because of back pain.
of various
factors
on inability
Work environment: Physical : heavy lifts, locked positions Psychological,
satisfactory
10%
comradeship
Individual factors: smoking, lifestyle etc. Bad medical
20% 10%
management
20%
Insurancebenefits Nachemson
to
40%
1990.
economically by 3 billion SEK per annum (Table 3). How can this goal be reached? An active attitude is required in the patient with back pain. Education is important. Let the patient know everything about backache-knowledge of its etiology and reassurance that back pain need not lead to life long disability. That pain on movement, and also on loading the back is not harmful. There is no danger in returning to work despite some pain in the back this will not necessarily predispose a recurrence. In other words information, instruction, insight and incessant-but still modulated-activity will lead to the incarnation of a healthy back. The proof of the success of these five i’s is well demonstrated in the good results obtained in back schools, and reported in epidemiologic studies and scientific assays of environment and work.
Table 3-Calculation disorders.
of benefit for Society with better care of back
1989 Million SW. Crowns (fl= 10.30 SW. Cr) Decreased
compensation
Decreased
early retirement
Increased
running
costs
Net profit for Society Jonsson
time
2700 700 150 3250
1990.
Neck and Shoulder Problems (and R.S.I.) Over the last few years greater attention has been paid to the neck-shoulder problem.10v l l The shoulder is connected with the trunk by one joint only-the sternoclavicular joint. Stability is maintained by the massive muscles which form one large complex combining the neck with the shoulder. It is thus not surprising that d’isorders of the neck can involve the shoulder and vice versa. Work involving the upper extremity in an abducted and/or flexed position will undoubtedly engage the neck without the head necessarily being moved or placed in any particular position. If this is the case it is suggested that the strain on the neck muscles will be further increased-
a strain which will be more pronounced if a work protection helmet is worn. There are certain groups who run a higher risk of occupational or load disorders. These are among men slaughterers, butchers, food store workers, painters and mechanics. Among women, mechanics, truck and crane drivers, butchers, seamstresses, dentists and computer operators appear to run the highest risks of neck shoulder disorders. It has been claimed that intervertebral disc degeneration may increase when excessive load is exerted on the cervical spine and that pain may result. This may be partly true as disc degeneration has been found to be 4-5 times more prevalent in dentists and miners than in the general population. The reason for this is thought to be excess neck loading. There are only weak correlations between radiographic disc degeneration and pain, discomfort and disability. It has been shown that for asymptomatic individuals the preparation with and without cervical disc degeneration is very much the same. Further, occupational stress from heavy jobs does not seem to be an important etiologic factor for degenerative cervical disc disease despite what has been said above. There is a problem called tension neck appearing in computer workers and in females working in heavy industry. The cause and pathology of this is not known and the diagnosis is made for an individual who in suffering discomfort in the neck, ascribes this to work and the doctor is at a loss to make a more specific diagnosis. The same can be said about a condition called OCD, occupational cervico-brachial disorder. It is met with in office clerks and computer workers who ascribe their discomfort to working conditions. Experts have tried to give a scientific explanation for the condition but failed. Instead a hypothesis is presented combining numerous factors believed, surmised, proposed, or suggested to serve as causative. The central point of interest is static load over time which is presumed to cause injury leading to pain, tiredness and local tenderness. The response to the static load is influenced by physical stress, concentration, lack of pauses, a ‘locked’ working position, too high a working speed and other factors. In summary the problems arise from physical load, mental stress, work organisation, personality and life style. All this reflects an attitude which has prevailed in Australia under the expression of ‘repetition strain injury’ (RSI). With time strong criticism has been raised and it has been suggested ‘. . . that medicine has become a disabling profession turning citizens into patients to be saved by the experts. The ‘RSI’ experience bears our the dangers of an expansionist profession, which transforms ‘ills’ into ‘illness’ to be treated by doctors until persons lose their ability to cope with indisposition or even with discomfort’; strong words but thoughtworthy. As for the neck and upper extremity it may not be too bold to conclude that the pathophysiology of use-
OCCUPATIONAL
associated symptoms
discomfort is indeterminate and that the complex defies current nosology.
DISORDERS
IN THE
LOCOMOTOR
SYSTEM
205
and knee. A study of this kind prompts further investigations in particular to identify specific exposure risks.
Osteoarthritis Finally, a problem of some concern is osteoarthritis. Can this be caused by heavy physical load on the weight bearing joints? Is deterioration of osteoarthrosis an age dependent process per se or does physical load increase the rate of degeneration? And symptoms--do they become aggravated by physical load? The medical answer is a slightly wavering no to all these questions. It is too well known that many people with advanced degenerative disease carry on their daily activities, including heavy work, without any discomfort. As long as this is a fact it will be difficult for many doctors to accept workload as a cause of both degeneration and symptoms. Some epidemiologic studies nevertheless support the assumption that heavy physical work load may contribute to osteoarthritis of both hip and knee. A study has been performed to seek any relationship between certain occupations with high physical workload and the development of severe osteoarthrotic changes in the hip and knee joint resulting in the need for hospital care. The population studies consisted of 5 15 174 persons from a census of 1980. The people held the same occupation in 1980 as they did in the censuses of 1960 and 1970. The study population was followed concerning hospital care for osteoarthrosis of the hip and knee during 1981 to 1983 by linkage to a Hospital Discharge Register. Different blue collar occupations were classified as being at high or low risk to major forces acting on the hip and knee; outcomes were compared. Male farmers. construction workers, firefighters and some processing workers had an excess risk of hospitalisation due to osteoarthritis of the hip and of the knee joint. Female postmen had an excess risk of osteoarthritis of the hip and female cleaners of the knee joint. The hypothesis was supported that heavy physical workload contributed to osteoarthrosis of both hip
Conclusions Despite the attempt to blame load factors for contributing to work incapacity questions can still be pertinently asked: how much work can disable an individual to the extent that work becomes impossible? It is not an uncommon finding that despite work being continual the alleged harmful effects cease. It seems that in the present sociopolitical climate that medical questions can be ignored or manipulated. In view of this the Swedish Orthopaedic Society has stated that medical experts need not be consultants. Are occupational disorders in the locomotor system myth or reality? If the ‘hypothetical realities’ of today can materialise in a scientifically acceptable manner the myth will vanish by tomorrow.
References I. Nachemson 2.
3. 4.
5. 6. 7. X. 9.
10. 1 I.
A. Work for All. For those with Low Back Pain As Well. Clin. Orthop 1983; 179: 77-85. Nachemson A. Ont i ryggen: Ryggproblemets omfattning. p. 1622. Prevention infiir framtiden. p. 78 82. Rapport fran SBU, Stockholm 1990. Kelsey J L. Epidemiology of musculoskeletal disorders. Oxford University Press, New York, 1982. Kelsey J. et al. An epidemiologic study of lifting and twisting on the job and risk for acute prolapsed lumbar intervertebral disc. J Orth Res 1984; 2: 61-66 Frymoyer J W, Rosen J C. Clements J. Psychologic factors m low-back-pain disability. Clin Orthop 1985; 195 : 178-l 84 Frymoyer J W, Mooney V. Occupational Orthopaedics. J Bone Joint Surg 1986: 68A: 469474 Pope M, Frymoyer J, Andersson G. Occupational low back pain. Praeger, New York, Greenwood Press Inc. 1984 Pope M. Impact and vibration and their effects on the lumbar spine. Thesis. University of Gothenburg, 1990 Schultz A. Andersson G, &tengren R, Haderspeck K, Nachemson A. Loads on the Lumbar Spine. J Bone Joint Surg 1987; 64A: 713-720 Troup J D G. Martin J W, Lloyd D C E F. Back Pain in Industry. Spine 1981; 6/l : 61-69 Videman T, Nurminen T, Tola S, Kuorinka I. Vanharanta H, Troup J D G. Low-Back Pain in nurses and some loading Factors of Work. Spine 1984; 9/4: 400-404