Work-related musculoskeletal disorders: Comparison of data sources for surveillance

Work-related upper extremity musculoskeletal disorders “associated with repeated trauma” account for more than 60% of all newly reported occupational illness, 332,000 in 1994 according to the U.S. Department of Labor. These numbers do not include, for example, those disorders categorized as “injuries due to overexertion in lifting,” approximately 370,000. Early identification of potential disorders and associated risk factors is needed to reduce these disorders. There are a number of possible methods for conducting surveillance for work-related musculoskeletal disorders (WMDs) based on health outcome: workers' compensation, sickness and accident insurance, OSHA 200 logs, plant medical records, self-administered questionnaires, professional interviews, and physical examinations. In addition, hazard surveillance based on evaluation of job exposures to physical stressors by nonoccupational health personnel is possible. As part of a large labor-management-initiated intervention study to reduce the incidence of WMDs in four automotive plants, we were able to compare the strengths and limitations of each of these surveillance tools. University administered health interviews yielded the highest rate of symptoms; combined physical examinations plus interview (point prevalence) rates were similar to self-administered questionnaires (period prevalence) rates. Plant medical records yielded the lowest rate of WMDs. WMD status on self-administered questionnaire and on physical examination were associated with risk factor exposure scores. This study suggests that symptoms questionnaires associated with risk factor exposure scores. This study suggests that symptoms questionnaires and checklist-based hazard surveillance are feasible within the context of joint labor-management ergonomics programs and are more sensitive indicators of ergonomic problems than pre-existing data sources. Am. J. Ind. Med. 31:600–608, 1997. © 1997 Wiley-Liss, Inc.     

Review of applicability of existing functional status measures to the study of workers with musculoskeletal disorders of the neck and upper limb

Both epidemiologic studies of the factors that contribute to the development of work-related musculoskeletal disorders of the neck and upper limb and intervention studies that test the effectiveness of workplace ergonomic and organizational changes are needed to provide empiric evidence for preventive strategies. This study reviews the relevance and comprehensiveness of existing functional status instruments for epidemiologic studies of work-related neck and upper limb disorders. Twelve domains were identified as the major areas of life affected by workers' neck and upper extremity disorder(s): work, household and family responsibilities, self-care, transportation/driving, sexual activity, sleep, social activities, recreational activities, mood, self-esteem, financial effects, and iatrogenic effects of assessments and treatment. Fifty-two functional status instruments were identified. Of these, 21 met the specified criteria as potentially relevant and were rated on the 3-point scale for relevance and comprehensiveness for each domain. None of the instruments covered all 12 domains adequately. © 1996 Wiley-Liss, Inc.     

Work organization is significantly associated with upper extremities musculoskeletal disorders among employees engaged in interactive computer-telephone tasks of an international bank subsidiary in São Paulo,Brazil

This study was designed to verify the risk factors for developing upper extremities musculoskeletal disorders (UEMD) among workers engaged in customer service tasks performed by telephone at a private banking corporation in São Paulo, Brazil. The monthly incidence of UEMD in hands and/or wrists in this group was studied retrospectively from January 1993 to June 1995. The statistical analysis was done by using multiple linear regression with the monthly incidence of UEMD considered as dependent variable in models controlled for age, seniority, mean daily regular worktime and overtime per operator, time pressure at work, rest/work schedule, management status, personnel training on postural and muscle stretching, and ergonomic hazards. The variables associated with UEMD were the following: time pressure at work (coefficient = 0.049; p = 0.008) and rest/work schedule (coefficient = −0.047; p = 0.02). The results indicate that working conditions are significantly associated with UEMD, and changes in the working schedule may decrease the incidence of this problem in workers assigned to tasks related to the interactive use of computer-accessible databases during telephone contacts. Am. J. Ind. Med. 31:468–473, 1997. © 1997 Wiley-Liss, Inc.     

Lack of concordance between the ICD-9 classification of soft tissue disorders of the neck and upper limb and chart review diagnosis: One steel mill's experience

The aim of this study is to determine the validity of the ICD-9 for diagnostic classification of soft tissue disorders of the neck and upper limb, using routinely collected data at a large steel company. The documentation in the clinical chart served as the gold standard. First, the overall accuracy of identifying these disorders from the ICD-9 was examined. Second, we examined whether the codes themselves, on an individual basis, accurately reflected the underlying problems as documented in the medical records. There were 1,267 new cases identified in 1991 by inclusion of all potentially applicable ICD-9 codes. Only 805 (63.5%) fulfilled the definition of a soft tissue disorder of the neck or upper limb as determined by chart review. A more restrictive strategy that only included cases coded by those ICD-9 codes that specifically pertain to these disorders yielded a higher proportion of true cases 458/480 cases (95.4%), but failed to identify the other 347 cases. The anatomical site of the problem could not be identified from the codes describing 651/1,267 cases (51.4%). There was poor agreement between the diagnostic labels recorded in the medical records and the ICD-9 codes, suggesting that many of the terms are being used interchangeably. Our results suggest that conclusions about these disorders drawn from analysis of administrative data which rely upon the ICD-9 for diagnostic classification must be interpreted cautiously. For these soft tissue disorders, researchers will need to develop strategies which would improve upon and supplement the ICD-9. © 1996 Wiley-Liss, Inc.     

Upper limb repetitive strain injuries in Manitoba

A review of workers' compensation board (WCB) claims in Manitoba, Canada identified an estimated 382 upper limb repetitive strain injury (RSI) claims or 9.3% of all upper limb WCB claims accepted in 1991. Tendonitis and carpal tunnel syndrome (CTS) were the most frequent diagnoses (27.5% and 19.3%, respectively). Rates of RSI were not significantly different by gender and age. RSI claimants had been experiencing symptoms for an average of 8 months prior to filing a compensation claim. While clerical occupations accounted for 13.6% of all upper limb RSI claims, the rates for RSIs in these occupations were low (0.67/1,000 workers), in contrast to occupations with the highest RSI rates: food, beverage, and related processing occupations (14.68/1,000 workers) and fabricating, assembling, and repairing of metal products (9.32/1,000). The highest risk industries were meat and poultry processing-related (23.48/1,000) and the manufacturing of airplanes (9.06/1,000). RSI claims were significantly more costly ($5,569 vs. $2,480, p <0.0001) and required more time loss (71.4 vs. 33.6 d. p <0.0001) than similar musculoskeletal non-RSI claims. Similarly, RSI claimants were less likely to return to the same job (67.3% vs. 81.0%, p <0.0001) than non-RSI claimants. It was concluded that the cost and severity of RSI claims militate for intensified preventive measures. © 1996 Wiley-Liss, Inc.     

Effects of work and rest on upper extremity signs and symptoms of workers performing repetitive tasks

The temporal relationship between work and signs and symptoms of upper extremity musculoskeletal disorders among workers at risk is relatively unexplored. The study focused on changes in upper extremity circumference, volume, sensory threshold, and reported symptoms after work and rest. All workers (N=50) performed a repetitive poultry processing task and had exhibited upper extremity signs and symptoms in baseline testing prior to this study. These workers manifested significantly increased upper extremity circumference following a period of rest, with circumferences decreasing during work. Upper extremity volume and reported swelling also decreased during work. Reports of tenderness were significantly greater after work than after rest, while reports of pain were greatest after a short rest interval. Results show that the signs and symptoms observed in these workers were manifestations of occupational cumulative trauma and that further study of the relationship between work and signs and symptoms is needed.     

Diagnosing soft tissue rheumatic disorders of the upper limb in epidemiological studies of vibration-exposed populations

Objectives

To investigate approaches adopted to diagnose soft tissue rheumatic disorders of the upper limb (ULDs) in vibration-exposed populations and in other settings, and to compare their methodological qualities.

Methods

Systematic searches were made of the Medline, Embase, and CINAHL electronic bibliographic databases, and of various supplementary sources (textbooks, reviews, conference and workshop proceedings, personal files). For vibration-exposed populations, qualifying papers were scored in terms of the provenance of their measuring instruments (adequacy of documentation, standardisation, reliability, criterion-related and content validity). Similar criteria were applied to general proposals for whole diagnostic schemes, and evidence was collated on the test–retest reliability of symptom histories and clinical signs.

Results

In total, 23 relevant reports were identified concerning vibration-exposed populations—21 involving symptoms and 9 involving examination/diagnosis. Most of the instruments employed scored poorly in terms of methodological quality. The search also identified, from the wider literature, more than a dozen schemes directed at classifying ULDs, and 18 studies of test–retest reliability of symptoms and physical signs in the upper limb. Findings support the use of the standardised Nordic questionnaire for symptom inquiry and suggest that a range of physical signs can be elicited with reasonable between-observer agreement. Four classification schemes rated well in terms of content validity. One of these had excellent documentation, and one had been tested for repeatability, agreement with an external reference standard, and utility in distinguishing groups that differed in disability, prognosis and associated risk factors.

Conclusions

Hitherto, most studies of ULDs in vibration-exposed populations have used custom-specified diagnostic methods, poorly documented, and non-stringent in terms of standardisation and supporting evidence of reliability and/or validity. The broader literature contains several question sets and procedures that improve upon this, and offer scope in vibration-exposed populations to diagnose ULDs more systematically.

     

Effects of peripheral nerve stimulation on paralysed upper limb functional recovery in chronic stroke patients undergoing low-frequency repetitive transcranial magnetic stimulation and occupational therapy: A pilot study

ObjectiveUpper limb paralysis, which is a sequela of stroke, limits patients’ activities of daily living and lowers quality of life. The objective of this study was to examine the effects of peripheral nerve stimulation on hemiparetic upper limb functional recovery in chronic stroke patients undergoing low-frequency repetitive transcranial magnetic stimulation and occupational therapy.MethodsThe subjects were chronic stroke patients who participated in a two-week inpatient programme including repetitive transcranial magnetic stimulation and occupational therapy. There were two groups of patients: the peripheral nerve stimulation group (11 patients who underwent peripheral nerve stimulation) and the control group (11 patients who previously participated in the same inpatient programme but without peripheral nerve stimulation, selected via propensity score matching). The peripheral nerve stimulation group had 1 h of peripheral nerve stimulation on the median and ulnar nerves during occupational therapy. The outcome measures were the Wolf Motor Function Test, Fugl-Meyer Assessment, and Motor Activity Log.ResultsWolf Motor Function Test, Fugl-Meyer Assessment, and Motor Activity Log showed significant improvement after the intervention in the peripheral nerve stimulation group. Particularly, the Fugl-Meyer Assessment hand score significantly improved in the peripheral nerve stimulation group compared to that in the control group (median change: 2 versus 0; p = 0.021, r = 0.49).ConclusionThe combined use of peripheral nerve stimulation with occupational therapy after repetitive transcranial magnetic stimulation may result in a better functional recovery of in hemiparetic upper limb. Peripheral nerve stimulation with stimulation above the sensory threshold and below the motor threshold is easy to combine with occupational therapy upper limb function training and is therefore clinically useful.     

Development of a Physical Examination for a Company-Based Management Program for Work-Related Upper Extremity Cumulative Trauma Disorders

The purpose of this project was to develop a streamlined upper extremity examination to be used in a company-based upper extremity CTD management program. Thirty-six symptomatic employees were examined by an occupational health nurse and categorized into those requiring further medical evaluation or those appropriate for conservative management. Backward logistic regression showed that the Appearance and Symmetry (AS) and the Neurological and Special Tests (NST) sections of the examination together explained 86.1% (p = 0.002) of the nurses categorical decisions. Based on these preliminary development data, a short screening examination was proposed.     

Detecting cumulative trauma disorders in workers performing repetitive tasks

On-site testing of 157 poultry processors disclosed that 50% had three or more abnormal upper extremity findings out of a total of 22 possibles. The average worker had five to six abnormal findings. Impaired pinch strength, decreased vibration sensitivity in the fingertips, and reports of current numbness were the most prevalent. Of workers with signs, 25% reported no symptoms, whereas only 8% of workers reported symptoms but had no signs. The investigators concluded that this measurement method has utility for assessments of worker populations to determine prevalence of CTDs and, potentially, for preclinical detection of these disorders to permit early intervention, reduce medical costs, and minimize disability. The need for accurate measurement to enhance early detection and prevention is discussed.     

A review of current literature on physiological tests and soft tissue biomarkers applicable to work-related upper limb disorders

Work-related upper limb disorders (WRULD) are among the most commonly reported occupational illnesses. Epidemiological evidence of work-relatedness has been reported for a number of conditions, including carpal tunnel syndrome, hand/wrist tendinitis, shoulder tendinitis and hand-arm vibration syndrome. A range of electrodiagnostic techniques and psychophysical tests has been used to assess neurological dysfunction associated with WRULD, whereas only very few studies have examined biochemical markers of soft tissue injury. This report reviews key literature on physiological tests and biochemical markers of musculoskeletal stress/injury, which are applicable to studies of WRULD. The paper concludes by proposing new ways that testing might be implemented during occupational health surveillance to enable early warning of impending problems and to provide more insight into the underlying nature of soft tissue disorders.     

Upper limb work-related musculoskeletal disorders among newspaper employees: Cross-sectional survey results

At a metropolitan newspaper office in Canada with extensive video display terminal (VDT) use, researchers carried out a survey (n = 1,007, 84% response) to establish baseline prevalence of work-related musculoskeletal disorders (WMSDs) and to identify demographic, postural, task, and psychosocial factors associated with WMSD symptoms. One-fifth of the respondents reported moderate or worse upper limb pain recurring at least monthly or lasting more than a week over the previous year. Logistic regression showed that employees who faced frequent deadlines and high psychological demands (fast work pace and conflicting demands), had low skill discretion and social support, spent more time keyboarding, or who had their screen in a non-optimal position were more likely to report moderate to severe symptoms. Women reported significantly higher levels of symptoms than men. Am. J. Ind. Med. 32:620–628, 1997. © 1997 Wiley-Liss, Inc.     

Repetitive industrial work and neck and upper limb disorders in females

A cross-sectional study was performed in which physical examinations of the neck and upper limbs were conducted on 82 currently working female industrial workers with exposure to repetitive work tasks and on 64 currently working referent subjects without exposure to repetitive work tasks. Associations between results of symptom questions and physical examination were sought with variables related to the work environment and to the individuals. In a multivariate model, there were statistically significant associations between exposure to repetitive work and diagnoses in both the neck/shoulders (prevalence odds ratio, POR = 4.6) and elbows/hands (POR = 3.5). In addition, age (POR = 1.9, 75th vs. 25th percentiles), tendencies towards subjective muscular tension (POR = 2.3), and stress/worry (POR = 1.9) were also associated with diagnoses in the neck/shoulders; however, there was not an association between these variables and the prevalence of diagnoses in elbows/hands. Standardized evaluation of videotape recordings in 74 of the industrial workers revealed significant associations between neck flexion, and elevation and abduction of the arm and the prevalence of neck/shoulder diagnoses. In the multivariate model, neck flexion was significantly associated with diagnoses in the neck/shoulders (p = 0.005). In addition, low muscle strength, lack of emotional well-being at work, and a variety of psychosomatic symptoms were associated with diagnoses in the neck/shoulders (all p < 0.001). Lack of strength was also associated with disorders of elbows/hands (p = 0.007). This study demonstrated a substantial prevalence of neck and upper limb disorders associated with repetitive work performed with a flexed neck and elevated and abducted arms, as well as a possible potentiation of these ergonomic factors by certain personal traits in some workers.     

The prevalence of work-related upper limb disorders in a printing factory

The association between problems of the upper limb and the workplaceis complex. A large printing manufacturer in the North Westof England sought the advice of both a surgeon, specializingin problems of the upper limb and an ergonomist in an attemptto control the frequency of these abnormalities amongst itsworkforce. The prevalence of these problems prior to and afterthe introduction of a number of recommendations was collatedand the results are discussed. Effectively the introductionof sensible and sympathetic modifications to the workplace appearedto reduce the number of upper limb disorders.     

Cross-sectional study of the relationship between repetitive work and the prevalence of upper limb musculoskeletal disorders.

BACKGROUND: This study examined the relationship of repetitive work and other physical stressors to prevalence of upper limb discomfort, tendinitis, and carpal tunnel syndrome. METHODS: Three hundred fifty-two workers from three companies participated. Job exposure levels for repetition and other physical stressors were quantified using an observational rating technique. Ergonomic exposures were rated on a 10-point scale, where 0 corresponded to no stress and 10 corresponded to maximum stress. Job selection was based on repetition (three categories: high, medium, and low) to ensure a wide range of exposures. Physical evaluations on all participating workers were performed by medical professionals and included a self-administered questionnaire, physical exam, and limited electrodiagnostic testing. RESULTS: Repetitiveness of work was found to be significantly associated with prevalence of reported discomfort in the wrist, hand, or fingers (odds ratio (OR) = 1.17 per unit of repetition; OR = 2.45 for high vs. low repetition), tendinitis in the distal upper extremity (OR = 1.23 per unit of repetition; OR = 3.23 for high vs. low repetition), and symptoms consistent with carpal tunnel syndrome (OR = 1.16 per unit of repetition; OR = 2.32 for high vs. low repetition). An association was also found between repetitiveness of work and carpal tunnel syndrome, indicated by the combination of positive electrodiagnostic results and symptoms consistent with carpal tunnel syndrome (OR = 1. 22 per unit of repetition; OR = 3.11 for high vs. low repetition). CONCLUSIONS: These findings indicate that repetitive work is related to upper limb discomfort, tendinitis, and carpal tunnel syndrome in workers. Further research with a wider range of exposures is needed to evaluate the effects of other physical stresses alone and in combination.     

Occupational stress and work-related upper extremity disorders: concepts and models

BACKGROUND: While research has suggested that interventions targeted at occupational stress (job stress) factors may improve clinical and work outcomes related to work-related musculoskeletal disorders, the emerging hypotheses relating occupational stress to work-related upper extremity disorders (WRUEDs) are not particularly well known among occupational health providers and researchers. METHODS: Generic job stress and health models and multivariable models of WRUEDs were described and evaluated. RESULTS: Models on occupational stress and health/WRUEDs offer unique perspectives on the role of occupational stressors on WRUEDs. However, the limited support for the structure and proposed mechanisms of these models suggest that investigations examining and validating proposed biobehavioral pathways are still needed. DISCUSSION: Difficulties in conceptualizing occupational stress have, in the past, hindered its systematic incorporation into occupational health research and prevention/intervention strategies. The present paper provides a common basis for researchers and practitioners with diverse backgrounds to understand job stress and its relation to WRUEDs in order to enhance future efforts. Given the present limitations in the field and the need for comprehensive approaches to WRUEDs, there is great potential for occupational health researchers and clinicians to advance knowledge in this area.     

Work-related cumulative trauma disorders of the upper extremity: navigating the epidemiologic literature

BACKGROUND: Cumulative trauma disorder of the upper extremity (CTDUE) is an umbrella term used to describe disorders resulting from repeated use of the upper extremity over time rather than a specific incident. The primary purpose of this article is to summarize the literature regarding the rate of work-related CTDUE, while drawing attention to the various factors contributing to the wide range of reported findings. METHODS: The Cumulative Index to Nursing and Allied Health and Medline databases were searched for articles focusing on etiology or rates of occurrence of work-related CTDUE and their findings were summarized. RESULTS: Potential reasons for rising rates, a gender differential, and the substantial range in rates and rate ratios are delineated and important factors to consider when interpreting rates derived from workers' compensation data are detailed. CONCLUSIONS: Future research should attempt to correctly identify more specific categories of CTDUE in well-defined and accurately-quantified "at risk" populations to provide more meaningful information regarding the epidemiology of CTDUE and the effectiveness of control activities.     

The psychosocial work environment and musculoskeletal disorders: design of a comprehensive interviewer-administered questionnaire

BACKGROUND: Psychosocial working conditions are likely to contribute to work-related musculoskeletal disorders (WRMSDs), but a lack of standardized measurement tools reflects both the theoretical and methodological limitations of current research. METHODS: An interdisciplinary team including biomedical, behavioral, and social science researchers used an iterative process to adapt existing instruments for an interviewer-administered questionnaire assessing psychosocial workplace exposure related to musculoskeletal disorders. RESULTS: The resulting questionnaire included measures of psychosocial workplace factors based on two theoretical models (the demand-control-support and the effort-reward imbalance models), supplemented by the additional constructs of "emotional demands," and "experiences of discrimination." Other psychosocial and physical measures selected for questionnaire inclusion address physical workload, sociodemographic and anthropometric characteristics, social relations and life events, health behaviors, and physical and psychological health. CONCLUSION: Using an interdisciplinary approach facilitated the development of a comprehensive questionnaire inclusive of key measures of psychosocial factors that may play a role in the complex mechanisms leading to WRMSDs.