Risk factors for hand-wrist disorders in repetitive work

Influence of brick laying height on biomechanical load in masons: Cross-sectional field study with technical measurements

BACKGROUND

Work-related musculoskeletal disorders (WMSDs) located in the low back and neck/shoulder regions are major concerns for both workers, workplaces, and society. Masons are prone to WMSD, because their work is characterized by repetitive work and high physical workload. However, the knowledge on the physical workload during bricklaying is primarily based on subjective measurements.

OBJECTIVE

This cross-sectional field study with technical measurements aimed to quantify physical workload in terms of muscular activity and degree of forward bending during bricklaying at different working heights among masons, i.e., knee, hip, shoulder, and above shoulder height.

METHODS

Twelve male (36.1±16.1 years) experienced masons participated in a cross-sectional field study with technical measurements. Surface electromyography from erector spinae longissimus and upper trapezius muscles and an inertial measurement unit-sensor placed on the upper back were used to assess the physical workload (level of muscle activation and degree of forward bending) different bricklaying heights. Manual video analysis was used to determine duration of work tasks, frequency, type, and working height. The working heights were categorized as 'knee', 'hip', 'shoulder', and 'above shoulder'. The 95 percentiles of the normalized Root Mean Square (RMSn) values were extracted assess from erector spinae and trapezius recordings to assess strenuous level muscle of muscle activation.

RESULTS

The RMSn of dominant erector spinae muscle increased from hip- to shoulder height (from 26.6 to 29.6, P < 0.0001), but not from hip to above shoulder height and decreased from hip to knee height (from 26.6 to 18.9, P < 0.0001). For the dominant trapezius muscle, the RMSn increased from hip- to shoulder- and above shoulder height (from 13.9 to 19.7 and 24.0, respectively, P < 0.0001) but decreased from hip- to knee height (from 13.9 to 11.5, P < 0.0001). Compared to hip height (27.9°), an increased forward bending was detected during bricklaying at knee height (34.5°, P < 0.0001) and a decreased degree of forward bending at shoulder- and above shoulder height (17.6° and 12.5°, P < 0.0001, respectively).

CONCLUSION

Based on technical measurements, bricklaying at hip height showed the best compromise between muscular load and degree of forward bending. This study contributes to the development of the work environment for masons and can help guide preventive initiatives to reduce physical workload.

Investigating gripping force during lifting tasks using a pressure sensing glove system

Lifting tasks remain one of the leading causes of musculoskeletal disorders (MSDs), primarily in the low back region. Lifting analysis tools are, therefore, designed for assessing the risk of low back pain. Shoulder musculoskeletal problems have emerged as common MSDs associated with manual handling tasks. It is hypothesized that gripping force is related to lifting conditions and may be used as a supplementary risk metric for MSDs in the shoulder and low back regions, because it measures additional hand exertions for coupling the lifted object during lifting. We assessed the capability tactile gloves for measuring the gripping force during lifting as a means for assessing different task conditions (lifting weight, lifting height, lifting direction, body rotation, and handle). Thirty participants wore the tactile gloves and performed simulated lifting tasks. Regression models were used to analyze the effects of the task variables on estimating the measured gripping force. Results demonstrated that 58% and 70% of the lifting weight variance were explained by the measured gripping force without and with considering the individual difference, respectively. In addition to the lifting risk measures commonly used by practitioners, this study suggests a potential for using gripping force as a supplementary or additional risk metric for MSDs.

Musculoskeletal health climate is associated with musculoskeletal pain and sickness absence among workers: a cross-sectional study

OBJECTIVES

This study aimed to investigate whether a musculoskeletal health climate, expressing the shared perceptions among workers concerning musculoskeletal health, is associated with number of musculoskeletal pain sites and sickness absence.

DESIGN

Cross-sectional study.

SETTING

Six slaughterhouses from 2 companies in Denmark and 6 home-nursing units and 12 nursing homes from 1 municipality in Jutland, Denmark.

PARTICIPANTS

A total of 1092 slaughter house workers and 410 care workers completed an online questionnaire from February to October 2019.

OUTCOME MEASURES

The exposure variable was musculoskeletal health climate assessed by two domains; (1) perceived management priority of musculoskeletal health measured by a modified subscale from the Nordic Safety Climate Questionnaire and (2) work group pain acceptance which was a modified version of the activity engagement subscale of the chronic pain acceptance scale. Outcomes variables were number of musculoskeletal pain sites (0-6) and days with sickness absence.

RESULTS

The associations between the two subscales, number of musculoskeletal pain sites and sickness absence were calculated using mixed linear and generalised estimating equation regression models. Higher perceived management priority scores were associated with a lower number of musculoskeletal pain sites across both job groups: β=-.57 (95% CI -0.91 to -0.23) and sickness absence (>5 days) due to musculoskeletal pain prevalence ratio (PR) 0.79 (95% CI 0.57 to 1.08). In contrast higher work group pain acceptance scores were associated with higher number of musculoskeletal pain sites: β=0.38 (0.11 to 0.66), whereas associations with sickness absences seemed to be modified by job groups; PR 1.59 care workers and PR 0.86 slaughterhouse workers.

CONCLUSION

The observed relationship between musculoskeletal health climate, musculoskeletal pain sites and sickness absence indicate that cultural factors should receive increased attention in work place preventive interventions.

Anthropometrics and electromyography as predictors for maximal voluntary isometric wrist torque: Considerations for ergonomists

The purpose of this study was to evaluate anthropometry and forearm muscle activity as predictors of maximal isometric wrist torque. Thirteen anthropometric measures, forearm electromyography from flexor carpi radialis (FCR) and extensor carpi radialis (ECR), and maximal isometric wrist flexion/extension torque were obtained from 25 male participants. Pearson correlation coefficients assessed relationships between peak isometric torque and: (1) anthropometrics, (2) FCR and ECR activation, (3) FCR/ECR antagonist/agonist coactivation ratios. Based on significant correlations, linear regression equations were developed (SPSS v.25; p < 0.05). Hand thickness, forearm circumference and ECR activation or hand thickness, elbow circumference, FCR activation and body weight were most highly correlated with extension or flexion torque, respectively. Hand thickness, forearm circumference, and ECR activation (R² = 54.5%; p = 0.001) and hand thickness, elbow circumference, FCR activation (R² = 68.3%; p < 0.001) explained similar variance in torque regressions as did the addition of body weight to extension (R² = 58.0%; p = 0.001) and flexion (R² = 69.9%; p < 0.001) torque regression equations, respectively. Circumference measurements, a pseudo for muscle size, and activation amplitude influenced wrist force output more than limb length or coactivation.

Repetitive and forceful movements of the hand as predictors of treatment for pain in the distal upper extremities

Objective

To investigate repetitive movements and the use of hand force as causes of treatment for distal upper extremities musculoskeletal disorders

Methods

A cohort of 202 747 workers in a pension health scheme from 2005 to 2017 in one of 17 jobs (eg, office work, carpentry, cleaning) was formed. Representative electro-goniometric measurements of wrist angular velocity as a measure for repetition and expert-rated use of hand force were used in a job exposure matrix (JEM). Job titles were retrieved from the Danish registers. Outcome was first treatment in the distal upper extremities. In a Poisson regression model, incidence rate ratios (IRRs) of treatment were adjusted for age, calendar-year, diagnosis of rheumatoid arthritis and arm fractures. In further analyses, wrist velocity or hand force was added.

Results

In men, wrist velocity had an IRR of 1.48 (95% CI 1.15 to 1.91) when the highest exposure level was compared with the lowest but with no clear exposure-response pattern. The effect became insignificant when adjusted for hand force. Hand force had an IRR of 2.65 (95% CI 2.13 to 3.29) for the highest versus the lowest exposure with an exposure-response pattern, which remained after adjustment for wrist velocity. Among women, no increased risk was found for hand force, while wrist velocity showed a significantly protective association with treatment.

Conclusions

In men, occupational exposure to hand force more than doubled the risk of seeking treatment. The results for exposure to repetition were less clear. In women, we could not find any indications of an increased risk neither for force nor for repetition.

Risk of pain in the neck and shoulders and job change among hairdressers: a combined questionnaire and register-based Danish prospective cohort study

Objective

To investigate whether intensity of work as a hairdresser was associated with treatments for pain, and if musculoskeletal pain was associated with leaving the hairdressing trade.

Methods

We formed two cohorts of hairdressers covered in the PensionDanmark Health Scheme (PDHS). Cohort 1 consisted of 1304 active hairdressers in 2009. Self-reported weekly haircuts were used as work intensity measure and treatments for pain in the neck and shoulders in PDHS were used as outcome. We used a Cox regression model with robust sandwich estimates adjusted for age, sex, employment status and prior treatment < 1 year before July 2009. Cohort 2 consisted of all hairdressers ever covered in the PDHS from 2006 to 2016 (n = 11,162). Exposure were treatments in PDHS within the last year. Outcome was leaving the trade within the following year. Adjustments were made for sex, calendar-year and age in Cox regression models.

Results

The adjusted hazard ratio of treatments in PDHS compared to the lowest work intensity was 0.95 (95% CI 0.58–1.55) and 0.74 (0.43–1.29) for medium and highest intensity, respectively. The risk of leaving the trade was lower, HR 0.80 (0.72–0.90) among hairdressers with treatments in PDHS within the last year, mainly driven by hairdressers aged < 56 years.

Conclusion

We found no association between intensity of work as a hairdresser, measured as self-reported weekly haircuts, and treatments for pain in PDHS. Furthermore, we found a protective effect of treatments in the PDHS within the last year on risk of leaving the trade.

Hand-Wrist Disorders in Chainsaw Operators: A Follow-Up Study in a Group of Italian Loggers

Despite the mechanization process implemented in arboriculture, logging tasks are still manually performed by chainsaw operators, which therefore are exposed to the risk of developing hand-wrist musculoskeletal disorders. Our research aimed to: (a) define whether the slight changes observed in 2017 showed an evolution to overt diseases; (b) study some risk determinants for these diseases such as age, working experience, and performing a secondary job. We recruited in a two-year follow-up study, 38 male forestry workers performing logging tasks employed in the Sicilian Forestry Department located in Enna. All the subjects underwent: (1) personal data collection; (2) administration of questionnaire addressed at upper limbs symptoms with a hand chart; (3) physical examination of the upper limbs, including Tinel’s and Phalen’s maneuvers; (4) ultrasound investigation of the hand-wrist area. In the two-year follow-up study we registered an overall increasing in wrist disorders, thus we can assume that forestry workers may be a target population for wrist diseases and deserve a particular attention in workers’ health surveillance programs. Interestingly, the prevalence of wrist-hand disorders resulted to be higher in younger workers.

Relationships and Mechanisms Between Occupational Risk Factors and Distal Upper Extremity Disorders

OBJECTIVE

The relationships between workplace risk factors and upper extremity injuries from epidemiological and laboratory studies were examined.

BACKGROUND

Epidemiological studies are associated with several limitations, affecting the strength of association between risk factors and the development of injuries.

METHOD

In this narrative review, we identified epidemiological and laboratory studies (published primarily since 1997) investigating exposure to workplace risk factors (force, repetition, posture, vibration) and risk of hand/wrist tendon-related disorders, epicondylitis, and carpal tunnel syndrome (CTS).

RESULTS

Forceful exertions are strongly associated with hand/wrist tendon-related disorders, epicondylitis, and CTS. Dose-response relationships were found for epicondylitis (repetition) and CTS (posture). Interactions demonstrate multiplicative effects of risk factors for injury risk. Laboratory studies display clear associations between task demands and biomechanical measures linked to mechanisms for upper extremity injuries with animal models providing further evidence of a dose-response between risk factors and injury.

CONCLUSION

Forceful, repetitive work requiring non-neutral postures are associated with increasing risk of hand/wrist tendon-related disorders, epicondylitis, and CTS as evidenced by epidemiology studies and laboratory-based investigations of humans and animals.

APPLICATION

Understanding the relationship between exposure levels of workplace risk factors and upper extremity disorders can improve injury prevention and rehabilitation strategies.

Development and evaluation of RAMP II - a practitioner's tool for assessing musculoskeletal disorder risk factors in industrial manual handling

RAMP II is an observation-based tool developed for assessing a wide range of musculoskeletal disorder risk factors related to industrial manual handling. RAMP II, which is part of the RAMP tool, is based on research studies and expert judgments. The assessment relies mainly on direct or video observations of the work being assessed, but additionally on measured push/pull forces and weights of handled objects, and on perceived workload and discomfort. Over 80 practitioners participated in the development of the tool. According to the evaluations, 73% of the assessment items evaluated had acceptable reliability, and the majority of the potential end-users reported that RAMP II is usable for assessing risks and as a decision base. It is concluded that this study provides support that RAMP II is usable for risk assessment of musculoskeletal disorder risk factors in industrial manual handling. Practitioner summary: RAMP II is an observation-based assessment tool for screening and assessing major musculoskeletal exposures in industrial manual handling jobs. Over 80 practitioners participated in the development of the tool. This study provides support that RAMP II is usable for risk assessment of musculoskeletal disorder risk factors in industrial manual handling. Abbreviations: CTS: carpal tunnel syndrome; HARM: the Hand Arm Risk Assessment method; IMP: intramuscular pressure; κ_w: linearly weighted kappa; LBD: lower back disorders; LBP: lower back pain; MAWL: maximum acceptable weight of lift; MHO: manual handling operations; MSD: musculoskeletal disorder; MNSD: neck-shoulder disorder; NSP: neck-shoulder pain; OCRA: the Occupational Repetitive Action methods; OHS: occupational health and safety; PABAK: prevalence and bias adjusted kappa; p₀: proportion of agreement; RAMP: Risk Assessment and Management tool for manual handling Proactively; ROM: range of motion; RPL: risk and priority level; RSI: the Revised Strain Index; RULA: the Rapid Upper Limb Assessment; SWEA: Swedish Work Environment Authority; UEMSDs: upper-extremity work-related musculoskeletal disorders; WMSD: work-related musculoskeletal disorder; WRMSD: work-related musculoskeletal disorder; workday_8h: eight hours workday.

Ergonomics and musculoskeletal symptoms in surgeons performing endoscopic procedures for benign prostatic hyperplasia

BACKGROUND AND PURPOSE

Benign prostatic hyperplasia (BPH) is the most common urologic disorder affecting older men, necessitating medical or surgical intervention. Limited data exists regarding the effect these surgeries have on the endourologist's musculoskeletal system following the surgery because of the required difficult posture, prolonged procedures, repetitive movements, and the settings of an adjustable visual display terminal workstation. The aim of our study was to survey the prevalence and possible causes of musculoskeletal disorders among endourologists performing transurethral resection of the prostate (TURP) or laser prostatectomy using either holmium laser enucleation or thulium laser enucleation.

MATERIALS AND METHODS

An email inviting all members of the Endourological Society to participate in the survey was sent. The questionnaire included different demographic and practice characteristics, with concern regarding performing either TURP or laser prostatectomy and the incidence and type of musculoskeletal incidents following these surgeries. All responses were collected by a commercially available internet based survey host (www.surveymonkey.com) over a period of 6 weeks.

RESULTS

Of the 121 complete responses, 84 (69%) of endourologists complained of a musculoskeletal disorder following TURP or laser prostatectomy. The most frequent complaint was for neck (64%), followed by back (57%), shoulder (48%), hand (40%), and elbow (18%). The average prostate volume turned out to be the most compelling predictor for musculoskeletal disorder occurrence with an average prostate volume of 76 g operated on by the complaining group compared with 59 g in the noncomplaining group. Those with more severe symptoms were linked to a mean prostate size of 80 g (60-146) and constantly complained of shoulder, neck, or back trouble compared with the less-severely complaining group.

CONCLUSIONS

A high prevalence of musculoskeletal complaints among urologists performing endourologic prostatectomy was confirmed and was found to be proportionally related to the size of the prostate. The integration of an ergonomic specialist inside the operation room to watch and correct the surgeon's position during endourologic procedures may reduce the endourologist's exposure to these occupational hazards.

Association between mobile phone use and neck pain in university students: A cross-sectional study using numeric rating scale for evaluation of neck pain

Objective

Mobile phones are reliable devices for communication and entertainment. However, their utilization for prolonged periods in flexed neck position is linked to neck and shoulders pain. The main purpose of this study is to investigate the association between neck pain and the duration of device use, taking into consideration gender, age, and the most frequent position in which students use their devices.

Subjects and methods

Based on a self-administered online questionnaire, we filled 500 questionnaires between February 15th, 2017 and March 18th, 2017. The study sample included healthy students from health care faculties regardless of their age, gender, or handedness.

Results

Analysis of the predictors for pain severity showed that age (p = 0.04) and duration of use (p = 0.001) were significantly associated with the severity of neck pain, while only the duration of use was significantly associated with pain duration (p = 0.036). Subjects were divided into two groups according to the pain score, 75.8% had pain severity equal or less than 4/10 and 24.2% had pain severity more than 4/10. Of those with pain severity >4, 5.8% of students sought medical help at the emergency department and 12.4% visited clinics, compared to only 0.3% seeking medical advice at an emergency department and 4.2% visiting clinics in the group with pain severity of ≤4 (p<0.001). Regarding the use of analgesia in the two groups, 44.6% of subjects with pain severity of >4 used analgesia, compared to only 12.1% in subjects with pain severity of ≤4 (p< 0.001).

Conclusion

This study demonstrates a significant positive correlation between the duration of mobile phone use and the duration and severity of neck pain. Furthermore, the increased severity of neck pain places a huge burden on the healthcare system.

Quantitative Measures of Physical Risk Factors Associated with Work-Related Musculoskeletal Disorders of the Elbow: A Systematic Review

Background: Work-related musculoskeletal disorders at the elbow are a common health problem, which highly impacts workers’ well-being and performance. Besides existing qualitative information, there is a clear lack of quantitative information of physical risk factors associated with specific disorders at the elbow (SDEs). Objective: To provide evidence-based quantitative measures of physical risk factors associated with SDEs. Methods: Studies were searched from 2007 to 2017 in Medline, EMBASE, and Cochrane Work. The identified risk factors were grouped in main- and sub-categories of exposure using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework for rating evidence. Results: 133 different risk-factor specifications were identified in 10/524 articles and were grouped into 5 main- and 16 sub-categories of exposure. The risk factors were significantly associated with lateral epicondylitis, medial epicondylitis, or ulnar neuropathy. Significant risk factors such as wrist angular velocity (5°/s, with increasing prevalence ratio of 0.10%/(°/s), or forearm supination (≥45° and ≥5% of time combined with forceful lifting) were found. Conclusions: This review delivers a categorization of work-related physical risk-factor specifications for SDEs with a special focus on quantitative measures, ranked for evidence. These results may build the base for developing risk assessment methods and prospective preventive measures.

Testing a strength and conditioning program to prevent common manipulative technique training injuries in chiropractic students: a study protocol for a randomised controlled trial

Background

Spinal manipulation is the primary therapy utilised by chiropractors in the management of their patients. The skills required may feel foreign to chiropractic students as they need strength and endurance in movement patterns they may not have otherwise been exposed to. This may lead to injury while learning manipulative techniques. It is plausible to suggest that the implementation of a strength and conditioning program early in a practitioner’s career could reduce the incidence and progression of injuries. The study aims to test the effectiveness of a strength and conditioning program in reducing the risk of chiropractic students’ acquiring injuries while learning the skill of spinal manipulation.

Methods

This study will involve a prospective cohort of chiropractic students who are currently learning manual therapy at an undergraduate level. Participants will be eligible for inclusion if they are enrolled in 3rd or 4th-year chiropractic manual therapy units at Murdoch University chiropractic course. The intervention group will follow a 12-week strength and conditioning program comprised of preventative exercises that address each body region previously identified as being prone to injury. The control group will complete a 12-week walking program. The primary outcome is injury rate, measured via a short questionnaire. The secondary outcome will be strength, measured via submaximal strength tests.

Discussion

The prescribed exercises are aimed at improving the strength and endurance of those muscle groups involved in commonly taught manual therapy tasks. The resistance bands have been chosen as they are inexpensive, simple to implement for the purposes of the study, and acceptably safe. A video format was selected to allow ease of access for participants, provide a detailed description and a visual representation of the exercises to be performed. A questionnaire was designed as a means to assess the influence of the strength and conditioning program on injury rate and the impact this may have on the students’ ability to continue practicing. The International Physical Activity Questionnaire has been chosen to measure the participants level of activity before beginning the exercise program.

Conclusion

This research protocol will be the first large-scale study to investigate the effectiveness of a strength and conditioning program to reduce injuries within chiropractic students learning manual therapy.

Trial registration

Australia New Zealand Clinical Trials Registry (ACTRN12617001638325p).

Electronic supplementary material

The online version of this article (10.1186/s12998-018-0192-0) contains supplementary material, which is available to authorized users.

Determinación de factores causantes de Tendinitis de Muñeca

Introducción. La tendinitis es una condición inflamatoria y degenerativa que se caracteriza por dolor en las intersecciones tendinosas de los huesos. La muñeca es uno de los sitios más comunes de tendinitis. La causa principal de tendinitis es la combinación de carga mecánica, uso intenso, movimientos repetitivos, fuerza y posición de la muñeca. Objetivos: Describir los factores asociados a tendinitis de muñeca producida en pacientes con diagnóstico clínico de tendinitis de muñeca. Métodos: Estudio descriptivo observacional, los participantes fueron 33 personas mayores de 18 años de edad con diagnóstico clínico de tendinitis de muñeca en consulta externa de cirugía de la mano. Resultados: Sí existe una relación importante entre los pacientes con diagnóstico clínico y sus condiciones laborales; mayormente la realización de movimientos manuales repetitivos, utilización de máquina de escribir o computadora y el uso de equipo que implique la fuerza entre los dedos pulgar e índice. Conclusión: Las condiciones laborales que impliquen el uso constante y crónico de la muñeca sí están relacionadas con el desarrollo de tendinitis de muñeca.

Evaluation of Pressure Pain Threshold as a Measure of Perceived Stress and High Job Strain

OBJECTIVE

To investigate whether pressure pain threshold (PPT), determined by pressure algometry, can be used as an objective measure of perceived stress and job strain.

METHODS

We used cross-sectional base line data collected during 1994 to 1995 within the Project on Research and Intervention in Monotonous work (PRIM), which included 3123 employees from a variety of Danish companies. Questionnaire data included 18 items on stress symptoms, 23 items from the Karasek scale on job strain, and information on discomfort in specified anatomical regions was also collected. Clinical examinations included pressure pain algometry measurements of PPT on the trapezius and supraspinatus muscles and the tibia. Associations of stress symptoms and job strain with PPT of each site was analyzed for men and women separately with adjustment for age body mass index, and discomfort in the anatomical region closest to the point of pressure algometry using multivariable linear regression.

RESULTS

We found significant inverse associations between perceived stress and PPT in both genders in models adjusting for age and body mass index: the higher level of perceived stress, the lower the threshold. For job strain, associations were weaker and only present in men. In men all associations were attenuated when adjusting for reported discomfort in regions close to the site of pressure algometry. The distributions of PPT among stressed and non-stressed persons were strongly overlapping.

CONCLUSIONS

Despite significant associations between perceived stress and PPT, the discriminative capability of PPT to distinguish individuals with and without stress is low. PPT measured by pressure algometry seems not applicable as a diagnostic tool of a state of mental stress.

Texting on mobile phones and musculoskeletal disorders in young adults: A five-year cohort study

The aim was to examine whether texting on a mobile phone is a risk factor for musculoskeletal disorders in the neck and upper extremities in a population of young adults. In a longitudinal population-based cohort study with Swedish young adults (aged 20-24 years) data were collected via a web-based questionnaire at baseline (n = 7092) and after one and five years. Cross-sectional associations were found between text messaging and reported ongoing symptoms in neck and upper extremities (odds ratios, ORs 1.3-2.0). Among symptom-free at baseline prospective associations were only found between text messaging and new cases of reported symptoms in the hand/fingers (OR 2.0) at one year follow up. Among those with symptoms at baseline prospective associations were found between text messaging and maintained pain in neck/upper back (OR 1.6). The results imply mostly short-term effects, and to a lesser extent, long-term effects on musculoskeletal disorders in neck and upper extremities.

Exposure-response relationships between movements and postures of the wrist and carpal tunnel syndrome among male and female house painters: a retrospective cohort study

OBJECTIVES

To investigate exposure-response relationships between measured movements and postures of the wrist and the incidence of carpal tunnel syndrome (CTS), and any modifications by sex.

METHODS

In 2011, we established a historical cohort of 9364 members of the Painters' Union in Denmark. Self-reported task distributions were obtained by questionnaire (53% responded) and combined with sex-specific task exposure matrices to get individual estimates of exposure intensity, that is, velocity of wrist flexion/extension, mean power frequency (MPF) and non-neutral wrist postures. Exposure duration was assessed from yearly working proportions. Registered first-time hospital discharge CTS diagnoses and CTS surgery were collected as outcomes. The cohort was followed from 1994 to 2010. Log-linear Poisson regression was used.

RESULTS

For CTS diagnoses, the adjusted incidence rate ratios (IRRs) increased with increasing wrist velocity (IRR=1.37 (95% CI 1.10 to 1.71) per °/s) and MPF (IRR=1.53 (95% CI 1.21 to 1.91) per 0.01 Hz). For CTS surgery, the results were similar. The outcomes were not related to non-neutral postures or exposure duration. The adjusted IRRs for women were higher than those for men. There were no multiplicative interaction effects between exposure intensity, exposure duration and sex. However, the absolute incidence rates (IRs) increased at a steeper rate for women than for men, indicating an additive interaction.

CONCLUSIONS

The incidence of CTS increased with increasing velocity of wrist flexion/extension and MPF of wrist movements. The relative increase in incidence rates was the same for women and men, but the absolute incidence rates increased at a steeper rate for women than for men.

The Impact of Physical and Ergonomic Hazards on Poultry Abattoir Processing Workers: A Review

The poultry abattoir industry continues to grow and contribute significantly to the gross domestic product in many countries. The industry expects working shifts of eight to eleven hours, during which workers are exposed to occupational hazards which include physical hazards ranging from noise, vibration, exposure to cold and ergonomic stress from manual, repetitive tasks that require force. A PubMed, Medline and Science Direct online database search, using specific keywords was conducted and the results confirmed that physical and ergonomic hazards impact on abattoir processing workers health, with harm not only to workers’ health but also as an economic burden due to the loss of their livelihoods and the need for treatment and compensation in the industry. This review endeavours to highlight the contribution poultry processing plays in the development of physical agents and ergonomic stress related occupational diseases in poultry abattoir processing workers. The impact includes noise-induced hearing loss, increased blood pressure, menstrual and work related upper limb disorders. These are summarised as a quick reference guide for poultry abattoir owners, abattoir workers, poultry associations, occupational hygienists and medical practitioners to assist in the safer management of occupational health in poultry abattoirs.

Brachial plexopathy: a case-control study of the relation to physical exposures at work

BACKGROUND

Work-related upper limb disorders constitute a diagnostic challenge. However, patterns of neurological abnormalities that reflect brachial plexus dysfunction are frequent in limbs with pain, weakness and/or numbness/tingling. There is limited evidence about the association between occupational physical exposures and brachial plexopathy.

METHODS

80 patients with brachial plexopathy according to defined criteria and 65 controls of similar age and sex without upper limb complaints were recruited by general practitioners. Patients and controls completed a questionnaire on physical and psychosocial work-exposures and provided psychophysical ratings of their perceived exposures. The exposures of cases and controls were compared by a Wilcoxon rank sum test. Odds ratios and dose-response relationships were studied by logistic regression.

RESULTS

Whether assessed as the extent during the workday or days/week, most physical exposures, in particular upper limb posture and repetition, were significant risk indicators with clear dose-response relationships. These findings were supported by psychophysical responses that also identified perceived work pace and the use of force as risk indicators. The identified psychosocial relations were limited to measures reflecting physical exposures.

CONCLUSIONS

While the identified risk indicators have previously been associated to upper limb symptoms as well as to diagnosed disorders other than brachial plexopathy, this study indicates an association between physical and work-exposures and brachial plexopathy. Longitudinal studies should be conducted in order to exclude bias from information and selection, both of which may occur with the applied case-control design.

Are forward bending of the trunk and low back pain associated among Danish blue-collar workers? A cross-sectional field study based on objective measures

The aim of this cross-sectional study was to investigate the association between the duration of objectively measured forward bending of the trunk and low back pain (LBP) intensity among 198 Danish blue-collar workers (male = 115; female = 83). The duration of forward bending of ≥ 30°, ≥ 60° and ≥ 90° was divided into high (the highest tertile) and low-moderate (the remaining tertiles) categories. High (>5) and low ( ≤ 5) pain intensities were categorised from a self-reported 0-9 scale. Results of multi-adjusted logistic regressions indicated no significant positive associations between forward bending and LBP intensity. On the contrary, higher duration of forward bending of ≥ 30° was associated with lower LBP intensity during all day (OR = 0.40; 95% CI, 0.15-1.02; p = 0.05) and work (OR = 0.44; 95% CI, 0.17-1.15; p = 0.09). This indication of a negative association may be explained by fear-avoidance behaviour of the blue-collar worker, job crafting or healthy worker effect.

Risks of musculoskeletal disorders among betel quid preparers in Taiwan

BACKGROUND

Betel quid chewing is common in Taiwan. The work of betel quid preparers is characterized by long hours of static work, awkward working posture and highly repetitive hand/wrist motion. However, the musculoskeletal health of betel quid preparers receives very little attention.

METHODS

The Chinese version of the Standardized Nordic Musculoskeletal Questionnaire (NMQ) was administered, and electrogoniometers and electromyography were used in this cross-sectional study to characterize the hand/wrist motion of the subjects. Physical examinations on the thumbs and wrists of the subjects were conducted by means of Phalen's test and Finkelstein's test, respectively.

RESULTS

Among the 225 participants, more than 95% attributed their musculoskeletal complaints to their work, and shoulder, neck, hand/wrist, and lower back discomfort were most frequently reported. More than 70% of the preparers did not seek medical treatment for their musculoskeletal problems. Based on the physical examination, 24% of the participants had suspected symptom of either carpal tunnel syndrome (CTS) or DeQuervain's tenosynovitis. The instrumental measurements indicated that betel quid preparation is characterized by extreme angle ranges and moderate repetition of wrist motion as well as low forceful exertion.

CONCLUSIONS

This study concludes that betel quid preparers are a high risk group of developing musculoskeletal disorders (MSDs). Future studies by electrogoniometers and detailed physical examination on betel quid preparers are needed to determine the predisposing factors for CTS. Some intervention measures to prevent MSDs and to lessen psychological stress for this group of workers are strongly suggested.

A prospective study of musculoskeletal outcomes among manufacturing workers: I. Effects of physical risk factors

OBJECTIVE

To better characterize associations between physical risk factors and upper-extremity musculoskeletal symptoms and disorders, a prospective epidemiologic study of 386 manufacturing workers was performed.

BACKGROUND

Methodological limitations of previous studies have resulted in inconsistent associations.

METHOD

An individual, task-based exposure assessment strategy was used to assess upper-extremity exertion intensity, repetition, and time-in-posture categories. Participants recorded time spent performing daily work tasks on a preprinted log, which was then used to calculate time-weighted-average exposures across each week of follow-up. In addition, a weekly Strain Index (SI) risk category was assigned to each participant. Incident musculoskeletal symptoms and disorders were assessed weekly. Proportional hazards analyses were used to examine associations between exposure measures and incident hand/arm and neck/shoulder symptoms and disorders.

RESULTS

Incident symptoms and disorders were common (incident hand/arm symptoms = 58/100 person-years (PY), incident hand/arm disorders = 19/100 PY, incident neck/shoulder symptoms = 54/100 PY, incident neck/shoulder disorders = 14/100 PY). Few associations between separate estimates of physical exposure and hand/arm and neck/shoulder outcomes were observed. However, associations were observed between dichotomized SI risk category and incident hand/arm symptoms (hazard ratio [HR] = 1.73, 95% confidence interval [CI] = [0.99, 3.04]) and disorders (HR = 1.93,95% CI = [0.85,4.40]).

CONCLUSION

Evidence of associations between physical risk factors and musculoskeletal outcome was strongest when exposure was estimated with the SI, in comparison to other metrics of exposure.

APPLICATION

The results of this study provide evidence that physical exposures in the workplace contribute to musculoskeletal disorder incidence. Musculoskeletal disorder prevention efforts should include mitigation of these occupational risk factors.

Physical activities at work and risk of musculoskeletal pain and its consequences: protocol for a study with objective field measures among blue-collar workers

Background

Among blue-collar workers, high physical work demands are generally considered to be the main cause of musculoskeletal pain and work disability. However, current available research on this topic has been criticised for using self-reported data, cross-sectional design, insufficient adjustment for potential confounders, and inadequate follow-up on the recurrent and fluctuating pattern of musculoskeletal pain. Recent technological advances have provided possibilities for objective diurnal field measurements of physical activities and frequent follow-up on musculoskeletal pain.

The main aim of this paper is to describe the background, design, methods, limitations and perspectives of the Danish Physical Activity cohort with Objective measurements (DPhacto) investigating the association between objectively measured physical activities capturing work and leisure time and frequent measurements of musculoskeletal pain among blue-collar workers.

Methods/design

Approximately 2000 blue-collar workers are invited for the study and asked to respond to a baseline questionnaire, participate in physical tests (i.e. muscle strength, aerobic fitness, back muscle endurance and flexibility), to wear accelerometers and a heart rate monitor for four consecutive days, and finally respond to monthly text messages regarding musculoskeletal pain and quarterly questionnaires regarding the consequences of musculoskeletal pain on work activities, social activities and work ability for a one-year follow-up period.

Discussion

This study will provide novel information on the association between physical activities at work and musculoskeletal pain. The study will provide valid and precise documentation about the relation between physical work activities and musculoskeletal pain and its consequences among blue-collar workers.

Upper limb cumulative trauma disorders for the orthopaedic surgeon

Work-related musculoskeletal disorders (WRMSDs) of the upper limb have become a serious concern in many countries and have been steadily progressing for several decades. The cause of WRMSDs is assumed to be the direct consequence of repetitiveness, extreme postures, and intensive efforts in a problematic psychosocial environment. Therapy should therefore associate the occupational physician and the regulatory bodies. It may be necessary to modify the individual workstation and to reorganize the company. Such upper limb pathologies may be surgically treated but the results are often delayed and poorer when compared to the general population.

Examining the interaction of force and repetition on musculoskeletal disorder risk: a systematic literature review

OBJECTIVE

Our aims were (a) to perform a systematic literature review of epidemiological studies that examined the interaction of force and repetition with respect to musculoskeletal disorder (MSD) risk, (b) to assess the relationship of force and repetition in fatigue failure studies of musculoskeletal tissues, and (c) to synthesize these findings.

BACKGROUND

Many epidemiological studies have examined the effects of force and repetition on MSD risk; however, relatively few have examined the interaction between these risk factors.

METHOD

In a literature search, we identified 12 studies that allowed evaluation of a force-repetition interaction with respect to MSD risk. Identified studies were subjected to a methodological quality assessment and critical review. We evaluated laboratory studies of fatigue failure to examine tissue failure responses to force and repetition.

RESULTS

Of the 12 epidemiological studies that tested a Force x Repetition interaction, 10 reported evidence of interaction. Based on these results, the suggestion is made that force and repetition may be interdependent in terms of their influence on MSD risk. Fatigue failure studies of musculoskeletal tissues show a pattern of failure that mirrors the MSD risk observed in epidemiological studies.

CONCLUSIONS

Evidence suggests that there may be interdependence between force and repetition with respect to MSD risk. Repetition seems to result in modest increases in risk for low-force tasks but rapid increases in risk for high-force tasks. This interaction may be representative of a fatigue failure process in affected tissues.

Effects of psychosocial work factors on lifestyle changes: a cohort study

OBJECTIVE

To evaluate the effect of the demand-control-support model, the effort-reward imbalance model, and emotional demands on smoking, alcohol consumption, physical activity, and body mass index.

METHODS

This is a 2-year prospective cohort study of 3224 public sector employees. Measures were assessed with questionnaires. Multiple regression analyses were used to predict changes in lifestyle factors.

RESULTS

Low reward predicted smoking, low-decision latitude predicted being inactive, and high demands predicted high-alcohol consumption but only for men at follow-up even after controlling for potential confounders. There were no other significant findings in the expected direction except for some of the confounders.

CONCLUSIONS

We found only limited and inconsistent support for the hypothesis that a poor psychosocial work environment is associated with an adverse lifestyle.

Optimising case definitions of upper limb disorder for aetiological research and prevention: a review

Experts disagree about the optimal classification of upper limb disorders (ULDs). To explore whether differences in associations with occupational risk factors offer a basis for choosing between case definitions in aetiological research and surveillance, we analysed previously published research. Eligible reports (those with estimates of relative risk (RR) for >1 case definition relative to identical exposures were identified from systematic reviews of ULD and occupation and by hand-searching five peer-review journals published between January 1990 and June 2010. We abstracted details by anatomical site of the case and exposure definitions employed and paired estimates of RR, for alternative case definitions with identical occupational exposures. Pairs of case definitions were typically nested, a stricter definition being a subset of a simpler version. Differences in RR between paired definitions were expressed as the ratio of RRs, using that for the simpler definition as the denominator. We found 21 reports, yielding 320 pairs of RRs (82, 75 and 163 respectively at the shoulder, elbow, and distal arm). Ratios of RRs were frequently ≤1 (46%), the median ratio overall and by anatomical site being close to unity. In only 2% of comparisons did ratios reach ≥4. We conclude that complex ULD case definitions (e.g. involving physical signs, more specific symptom patterns, and investigations) yield similar associations with occupational risk factors to those using simpler definitions. Thus, in population-based aetiological research and surveillance, simple case definitions should normally suffice. Data on risk factors can justifiably be pooled in meta-analyses, despite differences in case definition.

Hand problems among endourologists

BACKGROUND AND PURPOSE

Endourology has evolved rapidly for the management of both benign and malignant disease of the upper urinary tract. Limited data exist, however, on the occupational hazards posed by complex endourologic procedures. The aim of this study was to determine the prevalence and possible causes of hand problems among endourologists who routinely perform flexible ureteroscopy compared with controls.

MATERIALS AND METHODS

An online computer survey targeted members of the Endourological Society and psychiatrists in academic and community settings. A total of 600 endourologists and 578 psychiatrists were contacted by e-mail. Invited physicians were queried regarding their practice settings and symptoms of hand pain, neuropathy, and/or discomfort.

RESULTS

Survey responses were obtained from 122 (20.3%) endourologists and 74 (12.8%) psychiatrists. Of endourologists, 61% were in an academic setting and 70% devoted their practice to endourology. Endourologists were in practice for a mean 13 years, performing 4.5 ureteroscopic cases per week with a mean operative time of 50 minutes. Hand/wrist problems were reported by 39 (32%) endourologists compared with 14 (19%) psychiatrists (P=0.0486, relative risk [RR]=1.69). Surgeons who preferred counterintuitive ureteroscope deflection were significantly more likely to have problems (56%) compared with intuitive users (27%) (RR 2.07, P=0.0139) or those with no preference (26%) (RR 2.15, P=0.0451). Overall, most respondents (85%) with hand/wrist problems needed either medical or surgical intervention.

CONCLUSIONS

Hand and wrist problems are very common among endourologists. Future studies are needed to develop more ergonomic platforms and thereby reduce the endourologist's exposure to these occupational hazards.

1st place, PREMUS best paper competition: workplace and individual factors in wrist tendinosis among blue-collar workers--the San Francisco study

OBJECTIVE

Workplace studies have linked hand/wrist tendinosis to forceful and repetitive hand exertions, but the associations are not consistent. We report findings from a prospective study of right wrist tendinosis among blue-collar workers.

METHODS

Workers (N=413) at four industries were followed for 28 months with questionnaires and physical examinations every 4 months to identify incident cases of right wrist tendinosis. Exposure assessment of force and repetition were based on field measurements and video analysis to determine repetition rate and the percent time (% time) in heavy pinch (>1 kg-force) or power grip (>4 kg-force). All exposure variables were measured at the level of the individual and task. For workers responsible for >1 task, a time-weighted average exposure was calculated based on task hours per week. A proportional hazards model was used to assess the relationship between exposures and incidence of wrist tendinosis.

RESULTS

During the 481 person-years of follow-up, there were 26 incident cases of right wrist tendinosis [incidence rate (IR) 5.40 cases per 100 person-years]. Adjusting for age, gender, and repetition, wrist tendinosis was associated with % time spent in heavy pinch [hazard ratio (HR) 5.01, 95% CI 1.27-19.79). Composite exposure measure American Conference of Industrial Hygienists Threshold Limit Value (ACGIH-TLV) for hand activity level (HR 3.95, 95% CI 1.52-10.26) was also associated with the outcome for the medium-exposure group using video-based total repetition rate.

CONCLUSIONS

The workplace factors predicting wrist tendinosis were time-weighted average values of % time spent in heavy pinch and the ACGIH-TLV for Hand Activity Level. The % time spent in power grip was not a significant predictor, nor were any measures of repetition. An exposure-response relationship was observed for the % time spent in heavy pinch. These findings may improve programs for preventing occupational wrist tendinosis.

Tendon disorders of the hand and wrist

The terminology used to describe most common tendon disorders in the hand and wrist suggests that they are inflammatory in nature, although current evidence indicates that mechanical and degenerative factors are more important. Corticosteroid injections provide relief in 60% or more of cases; however, the duration of their effectiveness remains uncertain. Surgical release of the stenotic pulley or sheath is curative in well over 90% of cases; complications of surgery are rare, and relief is long-lasting. Enlightened management of these common problems demands evidence-based guidelines defining indications for surgery that will maximize outcomes and minimize costs.

Risk factors for work-related musculoskeletal disorders: A systematic review of recent longitudinal studies

OBJECTIVE

This systematic review was designed and conducted in an effort to evaluate the evidence currently available for the many suggested risk factors for work-related musculoskeletal disorders.

METHODS

To identify pertinent literature we searched four electronic databases (Cinahl, Embase, Medline, and The Cochrane Library). The search strategies combined terms for musculoskeletal disorders, work, and risk factors. Only case-control or cohort studies were included.

RESULTS

A total of 1,761 non-duplicated articles were identified and screened, and 63 studies were reviewed and integrated in this article. The risk factors identified for the development of work-related musculoskeletal disorders were divided and organized according to the affected body part, type of risk factor (biomechanical, psychosocial, or individual) and level of evidence (strong, reasonable, or insufficient evidence).

CONCLUSIONS

Risk factors with at least reasonable evidence of a causal relationship for the development of work-related musculoskeletal disorders include: heavy physical work, smoking, high body mass index, high psychosocial work demands, and the presence of co-morbidities. The most commonly reported biomechanical risk factors with at least reasonable evidence for causing WMSD include excessive repetition, awkward postures, and heavy lifting. Additional high methodological quality studies are needed to further understand and provide stronger evidence of the causal relationship between risk factors and work-related musculoskeletal disorders. The information provided in this article may be useful to healthcare providers, researchers, and ergonomists interested on risk identification and design of interventions to reduce the rates of work-related musculoskeletal disorders.

Management of work-relevant upper limb disorders: a review

BACKGROUND

Upper limb disorders (ULDs) are clinically challenging and responsible for considerable work loss. There is a need to determine effective approaches for their management.

AIM

To determine evidence-based management strategies for work-relevant ULDs and explore whether a biopsychosocial approach is appropriate.

METHODS

Literature review using a best evidence synthesis. Data from articles identified through systematic searching of electronic databases and citation tracking were extracted into evidence tables. The information was synthesized into high-level evidence statements, which were ordered into themes covering classification/diagnosis, epidemiology, associations/risks and management/treatment, focusing on return to work or work retention and taking account of distinctions between non-specific complaints and specific diagnoses.

RESULTS

Neither biomedical treatment nor ergonomic workplace interventions alone offer an optimal solution; rather, multimodal interventions show considerable promise, particularly for occupational outcomes. Early return to work, or work retention, is an important goal for most cases and may be facilitated, where necessary, by transitional work arrangements. The emergent evidence indicates that successful management strategies require all the players to be on side and acting in a coordinated fashion; this requires engaging employers and workers to participate.

CONCLUSIONS

The biopsychosocial model applies: biological considerations should not be ignored, but psychosocial factors are more influential for occupational outcomes. Implementation of interventions that address the full range of psychosocial issues will require a cultural shift in the way the relationship between upper limb complaints and work is conceived and handled. Dissemination of evidence-based messages can contribute to the needed cultural shift.

A systematic exploration of distal arm muscle activity and perceived exertion while applying external forces and moments

The purpose of this study was to systematically explore and describe the response of selected hand and forearm muscles during a wide range of static force and moment exertions. Twenty individuals with manual work experience performed exertions in power grip, pulp pinch and lateral pinch grips. Electromyography (EMG) from eight sites of the hand and forearm, grip force as well as ratings of perceived exertion (RPE) were monitored as each participant exerted approximately 350 short (5 s) static grip forces and external forces and moments. As expected, strong relationships were found between grip force alone without other actions and muscle activation. When the hand was used to grip and transmit forces and moments to the environment, the relationships between grip force and muscle activation were much weaker. Using grip force as a surrogate for forearm and hand tissue loading may therefore be misleading.