Determining causation of work-related upper extremity disorders

To determine causation in work-related upper extremity disorders, one must appreciate the philosophical constructs used in establishing causation and have clear definitions of the disorder in question. The preponderance of evidence does not support repetition as a major risk factor for physical injury. Terms such as "repetitive stress," "repetitive strain," and "cumulative trauma" should be abandoned, and we should educate our patients as to the multiple risk factors for upper extremity pain.     

Ergonomic considerations in work-related upper extremity disorders

Correctly applied, an ergonomics approach can reduce the likelihood of work-induced disorders and can assist in accommodating individuals who have work-related disorders, but it cannot eliminate disorders that have been mistakenly attributed to work by social processes. A contextual model of work-related upper extremity disorders is proposed that explicitly acknowledges that factors extrinsic to work can shape perceptions of upper extremity disorders and influence the process of somatic interpretation and health outcomes. Experiences in the United Kingdom of ergonomic regulations associated with computer use and the media coverage of work-related upper extremity disorders are used to illustrate this model.     

The role of imaging of work-related upper extremity disorders

Work-related upper extremity disorders can pose a diagnostic and management challenge because the nontraumatic disorders that are often believed to be caused by repetitive work activities can and do occur without any apparent provoking activity and can be caused or associated with many systemic medical conditions. One mainstay in the assessment of hand and arm disorders remains imaging. Imaging capabilities have made incredible advances with the advent of MRI, CT, ultrasound, bone scan, and numerous technologies that enable clinicians to view fine details of anatomy and pathology. This article reviews the potential imaging choices and clinical indications for work-related injuries of the elbow, hand, and wrist.     

Clinical and diagnostic features of upper extremity work-related musculoskeletal disorders

Upper extremity work-related musculoskeletal disorders, (UE-WMSDs) are one of the major causes of work-related disability in industrialized countries. Diagnostic criteria for many UE-WMSDs are still under debate, and several different national and international studies have attempted to reach a consensus agreement on the minimum criteria for case definition of UE-WMSDs. This paper describes clinical and diagnostic features of UE-WMSDs, focussing on carpal tunnel syndrome and rotary cuff tendinopathy.     

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.     

Prognosis of nonspecific work-related musculoskeletal disorders of the neck and upper extremity

Reviews of work-related musculoskeletal disorders (WMD) of the neck and upper extremity have typically supplied little information on prognosis. This paper reports on the methods and results of a systematic search for evidence on clinical course and prognosis of nonspecific WMD, i.e., those without specific clinical diagnoses. Articles were deemed relevant if they provided primary data on current or former worker cases of WMD followed over time. WMD status had to be based on clinical evaluations. The 13 studies which met these criteria were evaluated using clinical epidemiological criteria for validity of prognostic studies. None of the studies was sufficiently strong across the criteria to provide more than weaker evidence on prognosis. Prognostic factors with promise include duration of symptoms and workplace demands. In order to improve the evidence on prognosis of WMD, we recommend closer attention to the following: clear operational definition of cases; documentation of prognostic factors including duration of symptoms and severity at baseline; incorporation of multiple follow-up assessments; inclusion of a range of outcomes; and analysis using stratified or multivariate methods. © 1996 Wiley-Liss, Inc.     

Stress and work-related upper extremity disorders: implications for prevention and management

BACKGROUND: A causal link between stress and work-related musculoskeletal disorders of the upper extremities (WRUEDs) has been established, but there is less evidence for a beneficial effect of stress reduction interventions on WRUED symptoms and incidence. METHODS: Searches of Medline, Ergonomics Abstracts, and Psychlit from 1990 to 2001 identified studies that either targeted stress and measured WRUED outcomes, or described other interventions with both stress and WRUED outcomes. RESULTS: Workplace interventions, including discrete improvements in technology, work organization and ergonomics, and more comprehensive approaches can reduce levels of stress. In a few studies, these interventions have been associated with decreases in WRUED symptoms. Similar effects are noted in stress-related interventions targeting individuals before WRUEDs have appeared, and at several stages of these conditions. CONCLUSIONS: Health care providers can recognize stress-WRUED interactions through careful, directed inquiry. Both individual as well as workplace-targeted interventions, delivered in the primary care setting or workplace, may be helpful. Future research priorities include prospective studies of well-defined interventions, with ample measures of subject, intervention and workplace characteristics that can impact outcomes, and adequate follow-up to determine sustained effects.     

Rheumatic diseases that can be confused with work-related upper extremity disorders

Rheumatic illnesses are a common cause for musculoskeletal complaints in the general population. All ages can be affected, including people in the prime of their working years. Secondary problems, such as entrapment neuropathies, enthesopathies, and Raynaud's syndrome, can be associated with various inflammatory arthritides. A detailed history and physical are the most important tools in screening for potential inflammatory disease in workers with upper extremity complaints.     

Evaluation and management of chronic work-related musculoskeletal disorders of the distal upper extremity

This clinical review will describe the epidemiology, clinical presentation, and management of the following work-related musculoskeletal disorders (WMSDs) of the distal upper extremity: deQuervain's disease, extensor and flexor forearm tendinitis/tendinosis, lateral and medial epicondylitis, cubital tunnel syndrome, and hand-arm vibration syndrome (HAVS). These conditions were selected for review either because they were among the most common WMSDs among patients attending the New York State Occupational Health Clinics (NYSOHC) network, or because there is strong evidence for work-relatedness in the clinical literature. Work-related carpal tunnel syndrome is discussed in an accompanying paper. In an attempt to provide evidence-based treatment recommendations, literature searches on the treatment of each condition were conducted via Medline for the years 1985-1999. There was a dearth of studies evaluating the efficacy of specific clinical treatments and ergonomic interventions for WMSDs. Therefore, many of the treatment recommendations presented here are based on a consensus of experienced public health-oriented occupational medicine physicians from the NYSOHC network after review of the pertinent literature. A summary table of the clinical features of the disorders is presented as a reference resource.     

Psychosocial factors and the rehabilitation of patients with chronic work-related upper extremity disorders

This prospective cohort study investigated the effects of psychosocial factors on long-term employment outcome of a sample of chronic work-related upper-extremity pain disorder patients who had completed an interdisciplinary functional restoration program. Factors examined included the following: DSM-III-R Axis I and Axis II diagnoses, derived from the Structured Clinical Interview for DSM-III-R (SCID); history of childhood abuse experienced as elicited by the SCID; the Quantitated Pain Drawing, which evaluated perceived pain intensity; Million Visual Analog Scale, which measures perceived level of disability; and the Beck Depression Inventory, which assessed the level of depression. Results from univariate analyses demonstrated that return-to-work status 1 year following rehabilitation was predicted by the following psychosocial variables: The number of Axis I disorders, a past diagnosis of substance abuse, a past and/or current diagnosis of an anxiety disorder, a diagnosis of borderline personality disorder, a history of childhood abuse, self-report of depressed mood, and a moderate to high level of perceived disability. Additionally, age, race, length of disability, and prior surgical treatment predicted return-to-work rates. A multiple logistic regression further revealed that upper extremity patients who were older, Caucasian, had a current diagnosis of an anxiety disorder, and whose perception of their disability deteriorated from pre- to post-program were significantly less likely to return to work at one-year follow-up. Overall, the findings indicate that psychosocial variables influence the successful rehabilitation of patients with upper extremity disability, suggesting that these patients should be assessed and treated for psychosocial dysfunctions in conjunction with their rehabilitation so as to optimize favorable outcomes after treatment.     

Secondary prevention of work-related upper extremity disorders: recommendations from the annapolis conference

Introduction: Efforts to improve the secondary prevention of work-related upper extremity (WRUE) symptoms continue to present a challenge. As with many occupational musculoskeletal pain disorders no single, direct cause-effect relationship exists among specific exposures, pathologic processes, and symptoms. The field has yet to create truly effective and efficient interventions for these problems that are based on current epidemiological and clinical knowledge. Methods: A working conference was held in Annapolis, Maryland on September 23rd and 24th, 2005 with leaders in research and application related to upper extremity disorders to address this challenge. The intent of the meeting was to review “state of the art” evidence in epidemiology and intervention research in order to develop suggestions regarding next steps in intervention research and application. On day 2 a number of stakeholders were present to discuss what they perceived as the missing pieces in both epidemiological research and applied intervention research in order to generate more effective workplace interventions. Results: The papers in this series of the Journal of Occupational Rehabilitation indicate that scientifically sound progress has been made over the past decade in identifying ergonomic, workplace psychosocial, and individual factors in both the etiology and exacerbation of these symptoms/disorders. However, there is a gap between this knowledge and the development and practical implementation of comprehensive interventions for these problems. The conference also highlighted the paucity of economic analyses of the impact of these disorders as well as the economic study of the impact of intervention. Approaches for such evaluations were presented and are included in this special section of the journal. Conclusions: This series of papers and the summary of the invited group's discussions provided in this paper clearly emphasize the need for innovative ways to think about these problems and specific research topics that can help translate this knowledge into effective secondary prevention efforts.The opinions and assertions contained herein are the private views of the authors and not to be construed as being official or as reflecting the views of the Uniformed Services University of the Health Sciences or the Department of Defense.     

Development of a multidisciplinary research clinic for patients with work-related upper extremity disorders

The health care reform debate has focused attention on the need for outcomes research performed in ambulatory care settings. In this article, the authors describe the development of a research clinic focusing on symptomatic, functional, and vocational outcomes of patients with work-related upper extremity disorders. The authors describe the programmatic and research challenges associated with performing such research and emphasize the need for balancing the research and clinical agendas. Research efforts in this setting require careful consideration of the patient selection process and allocation of sufficient time for the clinical staff to collect and record essential research data.     

Biobehavioral mechanisms of work-related upper extremity disorders: a new agenda for research and practice

BACKGROUND: Epidemiological studies provide support for the role of organizational and individual psychosocial stressors in work-related upper extremity disorders (WRUEDs). Despite this evidence, the biological plausibility of a relationship between exposure to various psychosocial and work organizational stressors and WRUEDs remains unclear METHODS: The Georgetown Symposium on Biobehavioral Mechanisms of Work-Related Upper Extremity Disorders was held in Washington D.C. on November 6-7, 2000 to improve the understanding of potential biobehavioral mechanisms, identify future areas for research and discuss the implications of this body of knowledge for intervention. This meeting involved presentations and discussions by researchers and clinicians from a number of disciplines (epidemiology, occupational medicine, rheumatology, orthopedics, surgery, internal medicine, psychoneuroimmunology, occupational health psychology, behavioral medicine, psychophysiology and experimental and organizational psychology). RESULTS: The symposium generated several papers addressing the following topics: definitions and job stress models; epidemiological foundations; musculoskeletal and biomechanical models; central nervous system models of recurrent and persistent clinical pain; psychophysiology of work; and implications for intervention. These papers comprise this special issue. DISCUSSION: The present paper summarizes the various contributions to this special issue and provides direction for future research on potential biobehavioral pathways.     

Occupational and physical therapy for work-related upper extremity disorders: how we can influence outcomes

Upper extremity disorders in the workplace continue to be an economic strain on society. Physical and occupational therapy plays a crucial role in the management of the disorders. Medical providers should use therapists whose treatments demonstrate improvement in function and provide superior outcomes. Skilled therapy intervention requires that a therapist be able to identify and treat an injured worker in a holistic manner by looking at the whole individual, including issues that involve mechanical dysfunctions, psychosocial issues that include job satisfaction, and other age-related organic comorbidities. Therapists who work with injured employees must be highly skilled in identifying behavioral and organic disorders and must be confident in communicating these findings to various members of the health care team to help facilitate further medical testing.     

Development of a screen for predicting clinical outcomes in patients with work-related upper extremity disorders

This study prospectively examined the extent to which a set of medical, physical, ergonomic, occupational psychosocial, and individual psychosocial variables would predict clinical outcome associated with a diverse set of work-related upper extremity disorders in recently diagnosed individuals. This investigation was designed to develop a tool for use in a clinical setting to assist in identifying patients at risk for poorer outcome. Outcome was measured at 1, 3, and 12 months after completing a baseline questionnaire. Outcome status was based on a median split of a standardized composite index (symptoms, function, workdays lost, and mental health). Logistic regression indicated that predictors of poorer outcome at 1 month were: upper extremity comorbidity (risk ratio [RR], 1.58), pain severity (RR, 1.45), ergonomic risk exposure (RR, 1.07), low job support (RR, 1.03), and pain coping style (RR, 1.54). At 3 months, poorer outcome was predicted by: symptom severity (RR, 10.46), job stress (RR, 1.20), and pain coping style (RR, 1.98). The number of prior treatments/providers (RR, 1.77), past recommendation for surgery (RR, 6.43), and pain coping style were found to predict poorer outcome at 12 months. Sensitivity and specificity, respectively, for the models were 77.4% and 71.8% at 1 month, 80.6% and 82.4% at 3 months, and 80.6% and 83.3% at 12 months. The results indicate that baseline measures of ergonomic and psychosocial stress, pain severity, and pain coping style predict clinical outcome at shorter intervals, whereas number of past treatments/providers, recommendation for surgery and pain coping style predict longer-term outcome. The resulting prognostic screen provides a simple tool that assesses the multidimensional nature of work-related upper extremity disorders and predicts clinical outcome. Furthermore, the findings suggest the importance of early intervention that addresses both physical and psychosocial stressors at work. Specific recommendations to reduce the impact of observed risk factors are discussed.     

Employer,physical therapist,and employee outcomes in the management of work-related upper extremity disorders

The purpose of this study was to investigate the relationship among employer, provider, and patient outcome measures and how they are related to clinical factors and other occupation-related factors. Data were obtained from a New England workplace physical therapy (PT) clinic. Successful outcomes were defined as remaining-on/returning-to preinjury job (employer); achieving PT goals (provider); and increases in the SF-36 scale scores (patient). Variation in outcomes was explored across injury regions (shoulder, elbow, wrist/hand), work categories, number of visits, and length of PT care. Employer and provider outcomes are moderately correlated (phi coefficient = 0.51). Subjects demonstrated significant improvements in the SF-36 physical functioning and bodily pain scores after physical therapy intervention. Patients with elbow disorders needed more PT care and did not improve in the SF-36 role physical domain compared to shoulder and wristgroups (p < 0.05). Our results describe the relationship between outcome measures from different perspectives and the influence from other contributing factors. The impact of workplace injury management and the selection of outcome measures warrant continued study.     

Psychophysiology of work: stress,gender, endocrine response,and work-related upper extremity disorders

BACKGROUND: Mental stress may induce muscle tension and has been proposed to contribute to the development of work related upper extremity disorders (WRUEDs) by driving low threshold motor units into degenerative processes by overload. METHODS AND RESULTS: Measurements of perceived stress, catecholamines, blood pressure, and heart rate are associated with stress induced elevation of trapezius electromyographic activity. In repetitive tasks, where WRUEDs are common, psychophysiological arousal is generally high both during and after work. A possible explanation of the high prevalence of WRUEDs among women could be that women often are performing repetitive tasks and are exposed to additional stress from unpaid work. CONCLUSIONS: It is concluded that both physical and psychosocial work conditions may contribute to WRUEDs by inducing physiological stress and muscle tension.     

Relationship between stress and pain in work-related upper extremity disorders: the hidden role of chronic multisymptom illnesses

BACKGROUND: Pain and fatigue are commonly associated with work-related upper extremity disorders. Occasionally these symptoms persist beyond a reasonable healing period. One potential explanation for prolonged symptom expression is the concurrent development of a stress-mediated illness or CMI (Chronic Multi-Symptom Illness). In such a scenario, the chronic regional pain and other symptoms that the individual is experiencing would be attributable to the CMI rather than to tissue damage or a biomechanical dysfunction of the upper-extremity. METHODS: This article critically reviews the case definitions of the new class of CMI disorders and evaluates the existing evidence supporting centrally mediated physiological changes (e.g., sensory hypervigilance, dysautonomia) that manifest as symptoms of pain and fatigue in some individuals experiencing chronic stressors. RESULTS: While explanations for prolonged pain and fatigue have historically focused on mechanisms involving peripheral pathology or psychiatric explanations, ample evidences support the role of altered Central Nervous System function in accounting for symptom manifestation in CMI. CONCLUSIONS: A model is presented that unites seemingly disparate findings across numerous investigations and provides a framework for understanding how genetics, triggering events, stressors, and early life events can affect CNS activity. Resultant symptom expression (e.g., pain and fatigue) from central dysregulation would be expected to occur in a subset of individuals in the population, including a subset of individuals with work-related upper extremity disorders. Thus when symptoms such as pain and fatigue persist beyond a reasonable period, consideration of CMI and associated assessment and interventions focused on central mechanisms may be worthwhile.     

Sensory neural processing in work-related upper limb disorders

Pain in the upper limb is a common complaint in adults, and is often attributed to or exacerbated by occupational activities. In many patients there is no demonstrable pathology in the neck or arm to account for the symptom, and this has prompted the hypothesis that such cases might arise through abnormal neural processing of sensory information with a lowering of pain thresholds. In this paper we review the evidence in support of this theory and suggest directions for future research.