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Diagnostic criteria for upperlimbdisorders in epidemiological studies
The National !nstitute of Occupational Safety and I-iealth (NZOSH) in the USA has recently produced a book that reviews and assesses the quality of the large number of studies that have investigated whether work is a causative factor in recognized upper limb disorders such as carpai tunnel syndrome and epicondylitis ernard, 1997). This shows that many of the published papers have significant methodological problems and highlightsthe betterstudies. On reflection it seems surprising that, despite the large number of investigations on the effect of work 01: upper limb disorders, there remains so much disagreement and polarization. However, epidemiological research in this area is most difficult and there are many potential pitfalls: those who have not tried to perform such studies should not be too critical of those who have done their best to perform scientific research. One of the major problems with epidemiological research into upper limb disorders is that there is no estabhshed and widelji recognized set of diagnostic criteria for common conditions such as de Quervain’s disease and epicondyiitis vlhich can be effectively and reahstitally used when performing research and screening large numbers of people, most of whom will not have the disease under investigation. The diagnostic criteria used for upper limb disorders in epidemiological research vary from study to slrady and, though good pubhcations define their criteria, these are not listed in others. It is thus not surprising that different studies of similar design that investigate simiiar populations often report widely digering prevalences of upper limb disorders. Some studies report prevalences that are so high that they are difficult to believe and one must then wonder as to the validity of their diagnostic procedures. Unlike leukaemia, which can be reliably diagnosed with a blood test: no supportive investigations are readily available at a reasonable cost for use in epidemioiogical studies to confirm clinical diagnoses. Even if nerve conduction studies are used to screen for carpal tunnel syndrome, prob!ems are still encountered as they are time consuming, prone to technical problems when used in the field and the relationship between clinical carpal tunne! syndrome and abnormal nerve conduc5on is not entirely clear. For example how should one interpret abnormal. studies in asymptomatic patients? Epidemiological studies that base their diagnoses on questionnaire responses will inevitably have poor diagnostic power and could be compared to performing a questionaire study on tne prevalence of heart disease
the diagnostic Griteria. using chest pain as Epidemiological studies that include clinica! examinations (as good quality studies nowadays do) have improved diagnostic power but cannot be compared with each othe:, primariiy because of the absence of a universally recognized set of diagnostic criteria. In. order to address this problem the Health and Safety Executive (HSE) sponsored a Delphi exercise to establish diagnostic criteria for eight upper limb conditions (carpal tunnel syndrome. de Quervain’s disease, lateral epicondylitis, frozen shoulder, shoulder tendonitis, tenosynovitis, non-specific diffuse forearm pain and thoracic outlet syndrome) which are thought to commonly cause pain amongst the work force in the aJK_. Physicians and researchers from different specialties (epidemiology, general practice, hand surgery. neurophysiology, occupational medicine, physiotherapy, psychiatry and rheumatology) were asked to define their minimum diagnostic criteria for these eight conditions and these were then discussed at a consensus workshop in Birmingham at which all the above specialties were represented. A set of minimum diagnostic criteria were drawn up for seven of these conditions, none of which imslied work causation LHarrington et al, 1998). As thoracic outlet syndrome was not regularly diagnosed by any of the panel in the absence of definite neurological or vascular signs, it was felt inappropriate to produce a set of diagnostic criteria without the input of a proponent of this “condition”. Obviously as with any panel of “experts”, not everyone was happy with the diagnostic criteria of every condition and some readers will be concerned to find that nonspecific d&se forearm pain has been defined as a “condition”. However, non-specific forearm pain is a problem to occupational physicians that requires further investigation and it thus needs a set of diagnostic criteria jin fact it is a diagnosis by exclusion). Unlike “‘repetitive strain injury” this title does not imply causation or suggest a pathological entity and the presented criteria are a step forward in that this “condition” is distinguished from tenosynovitis. a term suffering from chronic abuse. The diagnostic criteria necessarily have to be relatively simple, in order to be practical, and are thus :lot perfect. They will inevitably not distinguish between the common condition under investigation and rarer diseases that mimic the condition, but i: is hoped that they will exclude other common conditions and attention is drawn to differenGa1 diagnoses in the or-i&al publication (Harrington et ai, 1991).
568
These diagnostic criteria oniy address one of the many problems encountered during epidemiological research and sadly any set of diagnostic criteria is only as good as the observer who performs the clinical examinations. If one presses hard enough tenderness can always be elicited over bony prominences and pulling discomfort on the back of the thumb during resisted thumb extension or “Finkelstein’s test” is often erroneously interpreted as demonstrating the presence of de Quervain’s disease. Further problems arise as no test is entirely specific for a particular condition and thus observers should be aware of common differential diagnoses and alternative explanations for positive tests. Et is also vital that, before making a diagnosis solely on the presence of positive tests, observers check that tests which should be negative are negative. If one only tests subjects for lateral epicondylar tenderness and pain on resisted wrist extension, one may fail to notice tenderness at other sites, or pain on other resisted joint movements and mislabel a case of “non-specific forearm pain” or *‘fibromyalgia” as lateral epicondylitis. Another consideration is that many cases of disease seen in epidemiological studies are mild and are never referred to a hand surgeon or require any treatment other Than simple conservative measures. These mild cases may only cause symptoms for a short period and the case de% nition of “disease” in many epidemiological studies is that symptoms have been present for a week or have troubled the study participant once a month for 1 year. With such a definition, transient non-specific muscle sprains and the aches and pains of advancing age could easily mimic mild cases of “disease” and it is thus vital that the diagnostic criteria have high specificity, as in epidemiological studies they will ine\/itably be used on many subjects without disease and only a few with the disease. Ideally, these clinical diagnostic criteria that rely on the exacerbation of clinical symptoms, will in time be replaced with tests that can identify pathology (for example MI?1 scans and nerve conduction studies). Such tests are needed to investigate the work causation of disease if conditions like epicondylitis, shoulder tendonitis and carpal tunnel syndrome are sometimes present, but asymptomatic. Mild degeneration of the common extensor origin (pathology of lateral epicondylitis) may be painless in a sedentary worker and go undetected in an epidemiological study whereas it may cause considerable discomfort in a heavy manual labourer. The use-relatedness of symptoms, which is common to all painful muscnloskeletal conditions, is a commcn cause of bias and all diagnostic criteria based on the presence of symptoms might be expected to demonstrate higher prevalences of “symprather than pathology, in manual tomatic disease”, workers. Thus a set of diagnostic criteria which do not rely on clinical symptoms and signs is needed to elucidate whether work causes disease or simply aggravates symptoms of diseases which have developed for other reasons.
The diagnostic criteria suggested in Birming;~am use in epidemiological studies were as foliows:
Pain, paraesthesia or sensory distribution and one C$
loss in the median
@ Tine12 test positive Phalen’s test positive e Nocturai exacerbation of symptoms * Motor loss with wasting of abductor @ Abnormal nerve conduction time.
f~hr
nerve
poliicis brevis
Pain on movement localized to the affected tendon of the pain by sheaths at the *wrist and reproduction resisted active movement of the affected tendons with the forearm stabilized.
Pain which is centered over the radial styloid ui~d tender swelling of the first extensor compartment arzd eitlzer @ Pain reproduced by resisted thumb @ Positive Finklestein’s test. Non-specijk d@xeJfoream
extension
01
pin
Pain in the forearm und failure to neet the diagnostic criteria for other specific diagnoses and diseases. Lateral epicondylitis Lateral epicondylar pain and epicondyiar pain on resisted extension of the wrist. Shoulder cap&is
tenderness
arz~i
(jk~~en shoulderj
History of unilateral pain in the deltoid area a& equal restriction of active and passive glenohumerai movement in a capsular pattern (external rotation > abduction > internal rotation)
History of pain in the deltoid more active movements:
region
md
pain
OP, 3ne
or
abduction for supraspinatus tendonitis external rotation for infraspinatus and teres minor tendonitis internal rotation for subscapularis tendonitis. icipitaI tendonitis should be considered -with a history of anterior shoulder pain and pain WI resisted active flexion of the elbow or supination of the forearm.
569
LPPER ‘,:MB DESORDhZS
criteria need lo Se tested for reliability a-d reproducibility and may need to be ever if all future epidemiological surveys modified. disorders use these criteria; then this will on upper undoubtedly be a step towards draining the quagmire of confusion on this subject. The
proposed
diagnostic
Hi:r:-q!.on J. CarLz;.!. Birreii i. definzionsfor UOI-1~ related tmironmen~ai
Gcmpertz 3 ;i398), Survei!lance case upper limb s! ndrome~. Occupat~o~x~l and Medicine. 55: 264.-271.
1 K C. Drn~s FRCS. Dqmtmenc of Cenr:e, ~ot~n_eham. SCi7ZUM.UK. 11 9OSThe Bnmh Society foorSurgq
eferences
Bernard
3 ? (Ed). MKSCulorkeicrui dimrch and wutkpiuce /a~mm. Cmcinnati. Centers for Dimm Control and Preventmn, Uaiional institute for Qccupalionai Sa:‘e:y and Health. 1997.
Trauma and Orthopaed~c Si~rgr!!. QUCCIIBVcdicdl
of the Hand
the diagnostic Griteria. using chest pain as Epidemiological studies that include clinica! examinations (as good quality studies nowadays do) have improved diagnostic power but cannot be compared with each othe:, primariiy because of the absence of a universally recognized set of diagnostic criteria. In. order to address this problem the Health and Safety Executive (HSE) sponsored a Delphi exercise to establish diagnostic criteria for eight upper limb conditions (carpal tunnel syndrome. de Quervain’s disease, lateral epicondylitis, frozen shoulder, shoulder tendonitis, tenosynovitis, non-specific diffuse forearm pain and thoracic outlet syndrome) which are thought to commonly cause pain amongst the work force in the aJK_. Physicians and researchers from different specialties (epidemiology, general practice, hand surgery. neurophysiology, occupational medicine, physiotherapy, psychiatry and rheumatology) were asked to define their minimum diagnostic criteria for these eight conditions and these were then discussed at a consensus workshop in Birmingham at which all the above specialties were represented. A set of minimum diagnostic criteria were drawn up for seven of these conditions, none of which imslied work causation LHarrington et al, 1998). As thoracic outlet syndrome was not regularly diagnosed by any of the panel in the absence of definite neurological or vascular signs, it was felt inappropriate to produce a set of diagnostic criteria without the input of a proponent of this “condition”. Obviously as with any panel of “experts”, not everyone was happy with the diagnostic criteria of every condition and some readers will be concerned to find that nonspecific d&se forearm pain has been defined as a “condition”. However, non-specific forearm pain is a problem to occupational physicians that requires further investigation and it thus needs a set of diagnostic criteria jin fact it is a diagnosis by exclusion). Unlike “‘repetitive strain injury” this title does not imply causation or suggest a pathological entity and the presented criteria are a step forward in that this “condition” is distinguished from tenosynovitis. a term suffering from chronic abuse. The diagnostic criteria necessarily have to be relatively simple, in order to be practical, and are thus :lot perfect. They will inevitably not distinguish between the common condition under investigation and rarer diseases that mimic the condition, but i: is hoped that they will exclude other common conditions and attention is drawn to differenGa1 diagnoses in the or-i&al publication (Harrington et ai, 1991).
568
These diagnostic criteria oniy address one of the many problems encountered during epidemiological research and sadly any set of diagnostic criteria is only as good as the observer who performs the clinical examinations. If one presses hard enough tenderness can always be elicited over bony prominences and pulling discomfort on the back of the thumb during resisted thumb extension or “Finkelstein’s test” is often erroneously interpreted as demonstrating the presence of de Quervain’s disease. Further problems arise as no test is entirely specific for a particular condition and thus observers should be aware of common differential diagnoses and alternative explanations for positive tests. Et is also vital that, before making a diagnosis solely on the presence of positive tests, observers check that tests which should be negative are negative. If one only tests subjects for lateral epicondylar tenderness and pain on resisted wrist extension, one may fail to notice tenderness at other sites, or pain on other resisted joint movements and mislabel a case of “non-specific forearm pain” or *‘fibromyalgia” as lateral epicondylitis. Another consideration is that many cases of disease seen in epidemiological studies are mild and are never referred to a hand surgeon or require any treatment other Than simple conservative measures. These mild cases may only cause symptoms for a short period and the case de% nition of “disease” in many epidemiological studies is that symptoms have been present for a week or have troubled the study participant once a month for 1 year. With such a definition, transient non-specific muscle sprains and the aches and pains of advancing age could easily mimic mild cases of “disease” and it is thus vital that the diagnostic criteria have high specificity, as in epidemiological studies they will ine\/itably be used on many subjects without disease and only a few with the disease. Ideally, these clinical diagnostic criteria that rely on the exacerbation of clinical symptoms, will in time be replaced with tests that can identify pathology (for example MI?1 scans and nerve conduction studies). Such tests are needed to investigate the work causation of disease if conditions like epicondylitis, shoulder tendonitis and carpal tunnel syndrome are sometimes present, but asymptomatic. Mild degeneration of the common extensor origin (pathology of lateral epicondylitis) may be painless in a sedentary worker and go undetected in an epidemiological study whereas it may cause considerable discomfort in a heavy manual labourer. The use-relatedness of symptoms, which is common to all painful muscnloskeletal conditions, is a commcn cause of bias and all diagnostic criteria based on the presence of symptoms might be expected to demonstrate higher prevalences of “symprather than pathology, in manual tomatic disease”, workers. Thus a set of diagnostic criteria which do not rely on clinical symptoms and signs is needed to elucidate whether work causes disease or simply aggravates symptoms of diseases which have developed for other reasons.
The diagnostic criteria suggested in Birming;~am use in epidemiological studies were as foliows:
Pain, paraesthesia or sensory distribution and one C$
loss in the median
@ Tine12 test positive Phalen’s test positive e Nocturai exacerbation of symptoms * Motor loss with wasting of abductor @ Abnormal nerve conduction time.
f~hr
nerve
poliicis brevis
Pain on movement localized to the affected tendon of the pain by sheaths at the *wrist and reproduction resisted active movement of the affected tendons with the forearm stabilized.
Pain which is centered over the radial styloid ui~d tender swelling of the first extensor compartment arzd eitlzer @ Pain reproduced by resisted thumb @ Positive Finklestein’s test. Non-specijk d@xeJfoream
extension
01
pin
Pain in the forearm und failure to neet the diagnostic criteria for other specific diagnoses and diseases. Lateral epicondylitis Lateral epicondylar pain and epicondyiar pain on resisted extension of the wrist. Shoulder cap&is
tenderness
arz~i
(jk~~en shoulderj
History of unilateral pain in the deltoid area a& equal restriction of active and passive glenohumerai movement in a capsular pattern (external rotation > abduction > internal rotation)
History of pain in the deltoid more active movements:
region
md
pain
OP, 3ne
or
abduction for supraspinatus tendonitis external rotation for infraspinatus and teres minor tendonitis internal rotation for subscapularis tendonitis. icipitaI tendonitis should be considered -with a history of anterior shoulder pain and pain WI resisted active flexion of the elbow or supination of the forearm.
569
LPPER ‘,:MB DESORDhZS
criteria need lo Se tested for reliability a-d reproducibility and may need to be ever if all future epidemiological surveys modified. disorders use these criteria; then this will on upper undoubtedly be a step towards draining the quagmire of confusion on this subject. The
proposed
diagnostic
Hi:r:-q!.on J. CarLz;.!. Birreii i. definzionsfor UOI-1~ related tmironmen~ai
Gcmpertz 3 ;i398), Survei!lance case upper limb s! ndrome~. Occupat~o~x~l and Medicine. 55: 264.-271.
1 K C. Drn~s FRCS. Dqmtmenc of Cenr:e, ~ot~n_eham. SCi7ZUM.UK. 11 9OSThe Bnmh Society foorSurgq
eferences
Bernard
3 ? (Ed). MKSCulorkeicrui dimrch and wutkpiuce /a~mm. Cmcinnati. Centers for Dimm Control and Preventmn, Uaiional institute for Qccupalionai Sa:‘e:y and Health. 1997.
Trauma and Orthopaed~c Si~rgr!!. QUCCIIBVcdicdl
of the Hand