Upper-limb Musculoskeletal Disorders Research Articles

Snap-fit assembly and upper limb functional limitations in automotive production workers: a nested case-control study.

The use of snap-fits in car-part assembling has developed into an industrial standard. Cross-sectional evidence indicates, however, that this assembling process might adversely affect workers' upper limb function. The objective of this study was to analyze incident cases of upper limb functional limitations (ULFL) in relation to exposure to snap-fit assembly. We performed a nested case-control study within a population of 5139 blue-collar automotive production workers. Cases with ULFL detected during follow-up were matched with controls based on employment duration and investigated on their exposure to snap-fit assembly. By conditional logistic regression, we modeled the risk for ULFL according to person-years of exposure to snap-fit assembly, adjusted for gender and baseline BMI. Overall, 64 ULFL cases were detected during a follow-up of 20610.8 person-years (3.1 cases per 1000 person-years). Cases, matched with an average of 4 controls, had significantly longer exposure duration to snap-fit assembly compared with controls (M = 1.15 person-years, SD = 1.68 person-years vs. M = 0.41 person-years, SD = 1.25 person-years). One person-year of exposure to snap-fit assembly was associated with an approximate 20% risk increase of developing ULFLs (OR 1.23, 95% CI 1.08-1.39). We confirm an association between accumulated exposure to snap-fits in car-part assembling and upper limb musculoskeletal disorders. Company physicians should thus be vigilant to symptoms of musculoskeletal disorders of the upper limbs in snap-fit assembly and support the development of threshold values for snap-fit insertion forces.

Personal and occupational factors contributing to biomechanical risk of the distal upper limb among dairy workers in the Lombardy region of Italy

Biomechanical overload in the wrist flexor and extensor muscles, together with awkward hand positions during work activities, can result in occupational wrist and hand disorders. Dairy workers, specifically those that work in the milking parlor, are exposed to highly repetitive and forceful exertions of the upper limb throughout their work shift. There are very few studies that have investigated the determinants that contribute to the risk of distal upper limb musculoskeletal disorders among dairy workers. The purpose of the present study was to identify the variables affecting the biomechanical overload of the distal upper limb among milking parlor workers, define risk profiles, and propose possible interventions to reduce the high physical loads to the distal upper limb during milking activities. Forty male workers from the three most common milking parlor systems in Lombardy Italy were recruited to participate in this study. Multiple correspondence analysis of personal characteristics and occupational risk factors, followed by cluster analysis, led to the identification of three distinct groups of workers. Low, medium and high risk profiles were assigned to each group based on the risk assessments performed using the Strain Index and electromyography of the distal upper limb. The main risk determinants were workstation characteristics, work organization and milking routine. A well-organized milking routine, milking cluster weight below 2.4 kg or the use of supporting arms for the milking cluster may reduce the risk of biomechanical overload.

Comparative Study of Aerobic Exercise and Weight training on Metabolic Syndrome among Breast Cancer Survivors

Introduction: Breast cancer is the most frequent-occurring cancer among women and the leading cause deaths. Despite this Breast cancer treatments still have side effects that may negatively impact recovery and quality of life (QOL) after initial treatments. BCRL is a chronic swelling of the arm, hand and associated trunk quadrant. It usually develops after damage to the axillary lymph nodes due to breast cancer therapies. Methods: Participants who had fulfilled the eligibility criteria were randomized to either the aerobic exercise group (n = 20) and weight training group (n = 20). Exercise program was divided into a warm-up period, moderate intensity of aerobic exercises, and cool-down period. Weight-training exercise of low to moderate intensity with relatively slow progression significantly improved the upper limb strength, lower limb strength and incidence of breast cancer-related lymphoedema. Outcomes were assessed at baseline and post intervention. Results: Outcome were assessed by the functional assessment of cancer therapy-breast (FACT-B) scale and 6 min walk test (6MWT) Depressive symptoms are assessed using the CES-D scale. Upper limb musculoskeletal disorders is assessed using the DASH (Disabilities of the Arm, Shoulder, and Hand) The results confirmed the hypothesis that 12 week of moderate-intensity aerobic exercise program significantly reduces BCRL. Conclusion: There have been many studies of resistance exercise in breast cancer survivors, Findings of this trial revels that aerobic exercise will contribute to the reduction of metabolic syndrome in best cancer survivors.

Upper Limb Musculosketal Disorder in Type 2 Diabetes Mellitus: A Cross Sectional Study

Introduction: Type 2 Diabetes mellitus (T2 DM) is common metabolic, chronic, multisystem disease involves joints, soft tissues and periarticular structures. The aim of our study was to investigate the type of upper limb musculoskeletal disorders (from shoulder to hand) in patients with type 2 diabetes mellitus.Materials and Method: Cross-sectional study at Department of Physical Medicine & Rehabilitation (PMR) in tertiary care setting.221 patients with T2DMaged between 35 to 70 years of age of either sex were included. Hand trauma, Physical labourer, Inflammatory arthritis, hypothyroidism, central or peripheral nervous system disease which includes cervical radiculopathy, and alcohol intake, were excluded from the study.Results: Out of 355 patients, 221 patients were selected and 134 patients were excluded. 58 patients of inflammatory arthritis, 23 cervical radiculopathy, 20 patient had disease duration of less than 2years, 15 had hypothyroidism, 7 was alcohol addicted, 6 labour worker, 4 had history of hand trauma and 1 had seizure. Out of 221 patients, 119 males and 102 females. Mean age was 52.45 years Mean duration of diabetes 8.9 yrs. ranged (1-24 years). The mean HbA1c was 7.3%. 42.6% of patients were overweight, 51.2% were obese & and 72.6% had hypertension. Shoulder involvement (48.86%) was the most common followed by hand (38.91%) followed by elbow in 12.16%). Adhesive capsulitis is the most frequent encountered problem found in about one third of patient, then Carpal Tunnel Syndrome in one seventh of cases, Loose Joint Mobility in one ninth& Flexor Tenosynovitis in one tenth of patient.Conclusion: Shoulder is involved in about half of the total upper limb involvement. Adhesive capsulitis is the most common manifestation of shoulder or overall upper limb musculoskeletal involvement. Carpal tunnel syndrome is the 2nd most common followed by limited joint mobility and flexor tenosynovitis.

Ergonomic interventions for preventing work-related musculoskeletal disorders of the upper limb and neck among office workers.

Work-related upper limb and neck musculoskeletal disorders (MSDs) are one of the most common occupational disorders worldwide. Studies have shown that the percentage of office workers that suffer from MSDs ranges from 20 to 60 per cent. The direct and indirect costs of work-related upper limb MSDs have been reported to be high in Europe, Australia, and the United States. Although ergonomic interventions are likely to reduce the risk of office workers developing work-related upper limb and neck MSDs, the evidence is unclear. This is an update of a Cochrane Review which was last published in 2012. To assess the effects of physical, cognitive and organisational ergonomic interventions, or combinations of those interventions for the prevention of work-related upper limb and neck MSDs among office workers. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, Web of Science (Science Citation Index), SPORTDiscus, Embase, the US Centers for Disease Control and Prevention, the National Institute for Occupational Safety and Health database, and the World Health Organization's International Clinical Trials Registry Platform, to 10 October 2018. We included randomised controlled trials (RCTs) of ergonomic interventions for preventing work-related upper limb or neck MSDs (or both) among office workers. We only included studies where the baseline prevalence of MSDs of the upper limb or neck, or both, was less than 25%. Two review authors independently extracted data and assessed risk of bias. We included studies with relevant data that we judged to be sufficiently homogeneous regarding the interventions and outcomes in the meta-analysis. We assessed the overall quality of the evidence for each comparison using the GRADE approach. We included 15 RCTs (2165 workers). We judged one study to have a low risk of bias and the remaining 14 studies to have a high risk of bias due to small numbers of participants and the potential for selection bias.Physical ergonomic interventionsThere is inconsistent evidence for arm supports and alternative computer mouse designs. There is moderate-quality evidence that an arm support with an alternative computer mouse (two studies) reduced the incidence of neck or shoulder MSDs (risk ratio (RR) 0.52; 95% confidence interval (CI) 0.27 to 0.99), but not the incidence of right upper limb MSDs (RR 0.73; 95% CI 0.32 to 1.66); and low-quality evidence that this intervention reduced neck or shoulder discomfort (standardised mean difference (SMD) -0.41; 95% CI -0.69 to -0.12) and right upper limb discomfort (SMD -0.34; 95% CI -0.63 to -0.06).There is moderate-quality evidence that the incidence of neck or shoulder and right upper limb disorders were not considerably reduced when comparing an alternative computer mouse and a conventional mouse (two studies; neck or shoulder: RR 0.62; 95% CI 0.19 to 2.00; right upper limb: RR 0.91; 95% CI 0.48 to 1.72), and also when comparing an arm support with a conventional mouse and a conventional mouse alone (two studies) (neck or shoulder: RR 0.91; 95% CI 0.12 to 6.98; right upper limb: RR 1.07; 95% CI 0.58 to 1.96).Workstation adjustment (one study) and sit-stand desks (one study) did not have an effect on upper limb pain or discomfort, compared to no intervention.Organisational ergonomic interventionsThere is very low-quality evidence that supplementary breaks (two studies) reduce discomfort of the neck (MD -0.25; 95% CI -0.40 to -0.11), right shoulder or upper arm (MD -0.33; 95% CI -0.46 to -0.19), and right forearm or wrist or hand (MD -0.18; 95% CI -0.29 to -0.08) among data entry workers.Training in ergonomic interventionsThere is low to very low-quality evidence in five studies that participatory and active training interventions may or may not prevent work-related MSDs of the upper limb or neck or both.Multifaceted ergonomic interventionsFor multifaceted interventions there is one study (very low-quality evidence) that showed no effect on any of the six upper limb pain outcomes measured in that study. We found inconsistent evidence that the use of an arm support or an alternative mouse may or may not reduce the incidence of neck or shoulder MSDs. For other physical ergonomic interventions there is no evidence of an effect. For organisational interventions, in the form of supplementary breaks, there is very low-quality evidence of an effect on upper limb discomfort. For training and multifaceted interventions there is no evidence of an effect on upper limb pain or discomfort. Further high-quality studies are needed to determine the effectiveness of these interventions among office workers.

The AFRETH Experience of Prevention and Education in French Spas Resorts

In the last years, prevention and education has emerged as a crucial issue for the chronic patients undergoing balneotherapy. General information on health and/or diseases can be offered through public conferences and the dissemination of leaflets. Thermal care facilities have a deep expertise in the delivery of practical education coming in the form of dedicated workshops. Particular programmes combining hydro-thermal cares, rehabilitation and education are also implemented. Law regulated programmes of patient therapeutic education (PTE) are frequently delivered in spa resorts. Scientific assessment of prevention and education is an important part of the AFRETH activity: 13 RCT have been dedicated to the actual medical benefit demonstration (5 have been published, 3 are in progress and 5 are ongoing) and 14 studies (8 RCT and 6 observational studies) have been dedicated to prevention and education interventions assessment. 6 studies have been published concerning prevention and/or education in post breast cancer rehabilitation (RCT), metabolic syndrome, psychotropic drug withdrawal, adapted physical activity, cognitive decline, chronic low back pain patients with sick-leave (RCT); three studies are in press: chronic venous insufficiency, frailty risk factors, overweight (RCT). In progress trials are assessing PTE in patients with fibromyalgia (RCT), upper limb musculoskeletal disorders (RCT), ecoached adapted physical activity (RCT). 3 RCT are ongoing: education in knee osteoarthritis, sleep disorders, prevention of falls in the elderly. The results of these different studies confirm the relevance of prevention and/or education delivered during spa therapy on weight control (Prisme, Pacthe), adapted physical activity (Pacthe, T Cap, MAPT), stress control (Specth, Pacthe), cognitive stimulation (MAPT), quality of life (Pacthe, TCap), sleep (Specth, Pacthe), activities (Tcap, Pacthe). The ongoing results will arguably confirm these first results and show the interest on pain control and falls prevention.

Impact of Upper Limb Musculoskeletal Disorders on Quality of Life in Type 2 Diabetes Mellitus

Impact of Upper Limb Musculoskeletal Disorders on Quality of Life in Type 2 Diabetes Mellitus

Functional incapacity related to rotator cuff syndrome in workers. Is it influenced by social characteristics and medical management?

Study DesignSurvey. IntroductionRotator cuff syndrome (RCS) is one of the most common musculoskeletal disorders reported in workers. The functional incapacity related to RCS may vary according to the sociodemographic context and to the medical management. Purpose of the StudyThe purpose of this is to analyze the RCS-related functional incapacity assessed by the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaires in workers according to their sociodemographic characteristics and the use of care. MethodsA cross-sectional study was carried out on a French sample of workers diagnosed with RCS. The DASH and DASH-work scores were studied according to the sociodemographic factors, musculoskeletal symptoms, and RCS medical management during the preceding 12 months. ResultsTwo hundred seven workers who suffered from RCS filled out the questionnaire of which 80% were still working. The DASH score was significantly higher in women (24.0 vs 17.4; P < .01; effect size (d) = 0.39), in patients over the age of 50 years (23.6 vs 11.3; P < .005) and in case of another upper limb musculoskeletal disorder (P < .0001; d ≥ 0.4). The DASH and DASH-work scores were significantly higher in case of use of care for RCS (P < .005; d > 0.6). DiscussionThe demographic factors and the RCS medical management influenced the overall incapacity assessed by the DASH questionnaire. Work incapacity was more especially related to the use of care for RCS. ConclusionThe sociodemographic and medical parameters added to other established predictors could help guide clinicians in managing their patients.

The comparison of frequency of the upper limb musculoskeletal disorders among patients with diabetes type II with normal cases.

Background and aimMusculoskeletal disease, that is recognized in diabetes and diabetes mellitus (DM) has shown a higher prevalence of chronic musculoskeletal complications. This study aimed at assessing the frequency of upper limb musculoskeletal disorders among patients with diabetes type II with normal cases in Mashhad, Iran.MethodsA cross-section of 100 patients with upper limb musculoskeletal disorders were enrolled in this study. The patients were examined by a unique physician considering carpal tunnel syndrome disorder, trigger finger, adhesive capsulitis, and Dupuytren’s contracture at Ghaem hospital, Mashhad, Iran in 2015. All collected data were recorded by using SPSS version 21 and were analyzed through independent-samples t-test for comparing changes, and Chi-square.ResultsIn this study, the mean age was 51.7±8.7 years old. Gender frequency was 114 (57%) male, and 86 (43%) female. There was no significant difference between groups in cases of gender frequency and mean of age (p>0.05). In evaluation of association between the two groups, there was significant difference for adhesive capsulitis, (p=0.04). Chi-square test showed significant association for age and adhesive capsulitis between the two groups, (p=0.040); but no other diabetes-related disorders, (p<0.05).ConclusionThe results of this study showed that in patients with diabetes mellitus and musculoskeletal complications such as upper limb musculoskeletal abnormalities, it will lead to an increase in skeletal muscle effects in DM patients. It is recommended that musculoskeletal examination is done periodically in DM patients for identification of these disorders and necessary actions are carried out for prevention of the disorders as soon as possible.

Risk assessments using the Strain Index and the TLV for HAL, Part II: Multi-task jobs and prevalence of CTS

ABSTRACTThe Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value for hand activity level (TLV for HAL) have been shown to be associated with prevalence of distal upper-limb musculoskeletal disorders such as carpal tunnel syndrome (CTS). The SI and TLV for HAL disagree on more than half of task exposure classifications. Similarly, time-weighted average (TWA), peak, and typical exposure techniques used to quantity physical exposure from multi-task jobs have shown between-technique agreement ranging from 61% to 93%, depending upon whether the SI or TLV for HAL model was used. This study compared exposure-response relationships between each model-technique combination and prevalence of CTS.Physical exposure data from 1,834 workers (710 with multi-task jobs) were analyzed using the SI and TLV for HAL and the TWA, typical, and peak multi-task job exposure techniques. Additionally, exposure classifications from the SI and TLV for HAL were combined into a single measure and evaluated. Prevalent CTS cases were identified using symptoms and nerve-conduction studies. Mixed effects logistic regression was used to quantify exposure-response relationships between categorized (i.e., low, medium, and high) physical exposure and CTS prevalence for all model-technique combinations, and for multi-task workers, mono-task workers, and all workers combined.Except for TWA TLV for HAL, all model-technique combinations showed monotonic increases in risk of CTS with increased physical exposure. The combined-models approach showed stronger association than the SI or TLV for HAL for multi-task workers.Despite differences in exposure classifications, nearly all model-technique combinations showed exposure-response relationships with prevalence of CTS for the combined sample of mono-task and multi-task workers. Both the TLV for HAL and the SI, with the TWA or typical techniques, appear useful for epidemiological studies and surveillance. However, the utility of TWA, typical, and peak techniques for job design and intervention is dubious.

Review on Pen and Paper Based Observational Methods for Assessing Work-related Upper Limb Disorders

This review aims to give an overview of current techniques available for pen and paper based observational methods in assessing work-related upper limb disorders. Searched from an electronic database for materials from 1993 until 2015, the methods discovered were based on upper limb disorders, observational method, risk factors and musculoskeletal disorders. The evaluation process for selected publication has been conducted by two researchers. Seven observational methods used to assess exposure to work-related Upper Limb Disorders (ULDs)were identified. The risk factors involved in current techniques of pen and paper based observational tools were postures, force, repetition, vibration, movement, frequency of action and duration. From the seven methods, only three methods were proven to be reliable and rated as moderate to good. For the three methods reviewed, the validity test showed moderate results. Many observational tools exist, but no single tool appears to cover all of the risk factors which is related to upper limb. Although the most important factor in developing tool is proper validation of exposure assessment techniques, the existing observational method did not test reliability and validity.

Proposing a new index to quantify instantaneous symmetry during manual wheelchair propulsion

Propelling a manual wheelchair (MWC) is a strenuous task that causes upper limb musculoskeletal disorders (MSD) in a large proportion of MWC users. Although most studies on MWC propulsion biomechanics assume that MWC propulsion is a relatively symmetric task, recent literature suggests that this is the case only when the assessed outcome measures are averaged over long periods of time, and not over short periods (i.e., instantaneously). No method is currently available to assess instantaneous symmetry. In this work, we present the Instantaneous Symmetry Index (ISI), a new method that quantifies how a variable has been instantaneously asymmetric during a selected time period. Thirteen experienced MWC users propelled on different cross slopes of 0%, 2%, 4%, 6% and 8%. As the cross slope is increased, the upper hand produced less propulsive moments and the lower hand produced more propulsive movements. This has been reflected in the ISI, which increased from 0.20 (0% slope) to 0.84 (8% slope) with a Spearman׳s coefficient of 0.90. The ISI has great potential to evaluate the ability of a user to propel symmetrically and synchronously, and will be a relevant measure to include in future studies on the impact of MWC propulsion asymmetry on MSD risk.

Tool development to assess the work related neck and upper limb musculoskeletal disorders among female garment workers in Sri-Lanka.

Musculoskeletal disorders (MSDs) have been identified as a predisposing factor for lesser productivity, but no validated tool has been developed to assess them in the Sri- Lankan context. To develop a validated tool to assess the neck and upper limb MSDs. It comprises three components: item selections, item reduction using principal component analysis, and validation. A tentative self-administrated questionnaire was developed, translated, and pre-tested. Four important domains - neck, shoulder, elbow and wrist - were identified through principal component analysis. Prevalence of any MSDs was 38.1% and prevalence of neck, shoulder, elbow and wrist MSDs are 12.85%, 13.71%, 12%, 13.71% respectively. Content and criterion validity of the tool was assessed. Separate ROC curves were produced and sensitivity and specificity of neck (83.1%, 71.7%), shoulder (97.6%, 91.9%), elbow (98.2%, 87.2%), and wrist (97.6%, 94.9%) was determined. Cronbach's Alpha and correlation coefficient was above 0.7. The tool has high sensitivity, specificity, internal consistency, and test re-test reliability.

Optimizing Positioning for In-Office Otology Procedures.

Objective Surgeons often report musculoskeletal discomfort in relation to their practice, but few understand optimal ergonomic positioning. This study aims to determine which patient position-sitting versus supine-is ergonomically optimal for performing otologic procedures. Study Design Observational study. Setting Outpatient otolaryngology clinic setting in a tertiary care facility. Subjects and Methods We observed 3 neurotologists performing a standardized simulated cerumen debridement procedure on volunteers in 2 positions: sitting and supine. The Rapid Upper Limb Assessment (RULA)-a validated tool that calculates stress placed on the upper limb during a task-was used to evaluate ergonomic positioning. Scores on this instrument range from 1 to 7, with a score of 1 to 2 indicating negligible risk of developing posture-related injury. The risk of musculoskeletal disorders increases as the RULA score increases. Results In nearly every trial, RULA scores were lower when the simulated patient was placed in the supine position. When examined as a group, the median RULA scores were 5 with the patient sitting and 3 with the patient in the supine position ( P < .0001). When the RULA scores of the 3 neurotologists were examined individually, each had a statistically significant decrease in score with the patient in the supine position. Conclusion This study indicates that patient position may contribute to ergonomic stress placed on the otolaryngologist's upper limb during in-office otologic procedures. Otolaryngologists should consider performing otologic procedures with the patient in the supine position to decrease their own risk of developing upper-limb musculoskeletal disorders.

Exposure to whole body vibration in heavy mine vehicle drivers and its association with upper limbs musculoskeletal disorders

Background: Vibration as one of the harmful physical factors is relatively present in a wide range of jobs. Musculoskeletal disorders (MSDs) are among the most prevailing complaints of workers encountering occupational factors for example vibration. Therefore, this study was conducted to investigate vibration and its association with the MSDs in upper limbs of heavy mine vehicles drivers. Materials and Methods: This cross-sectional study was conducted, on heavy mine vehicles of GolGohar Sirjan Centre, Sirjan, Iran. In general, 288 drivers with 92 vehicles were working at the mine site. SVAN958 vibration meters and the Nordic Musculoskeletal Questionnaire were used to measure whole body vibration and upper limb MSDs, respectively. Finally, the data were analysed using SPSS. Results: The highest average equilibrated acceleration was in graders (2.179 m/s2 ) and drills had the lowest average acceleration (0.479 m/s2 ). Prevalence of MSDs within past 12 months showed a significant difference in the neck (P = 0.044) and elbow (P = 0.023) between case and control group. The whole body vibration variable was associated with MSDs in the neck (P = 0.020) and wrist/hands (P = 0.030), and with increase in vibration the MSDs showed a 59% increase in neck and 72% in wrist/hands. In multivariate analysis, the whole body vibration variable had a significant relation with MSDs in wrist/hand (P = 0.027) and caused an 83% increase in the risk of MSDs per each unit in wrist/hand. Conclusions: The prevalence of disorders in studies with short duration is probably not quite visible; however, by increasing the working experience with these vehicles which have higher vibration than standard rates, the chance of developing MSDs increases.

Evaluation of ‘I-Preventive’: a digital preventive tool for musculoskeletal disorders in computer workers—a pilot cluster randomised trial

ObjectivesI-Preventive is a digital preventive tool for musculoskeletal disorders (MSDs) in computer workers. We sought to determine its impact on pain in computer workers with upper limb MSDs and visual discomfort.MethodsWe conducted a pilot cluster randomised trial in 2 different sites of a tyre factory in France. We randomised 200 employees to either an intervention group (I-Preventive) or control group, each comprising symptomatic and asymptomatic employees. The workers were followed up for 5 months. The main outcome was overall recovery from symptoms following 1 month's intervention based on Nordic-style and eyestrain questionnaires.ResultsWe included 185/200 workers: 96 in the intervention group (mean age 41.8±1.4 years; 88.5% males) and 79 in the control group (mean age 42.9±12.0 years; 94.5% males). The most painful areas (numerical scale ≥2) were the neck (40.0%), upper back (18.8%) and shoulders (15.7%). For the most painful anatomical area, the Nordic score significantly decreased after 1 month in the intervention group (p=0.038); no change was observed in the control group (p=0.59). After 1 month's use, the intervention group reported less pain in the painful area and less visual discomfort symptoms (p=0.02). Adherence to the I-Preventive program was 60%.ConclusionsI-Preventive is effective in the short term on musculoskeletal symptoms and visual discomfort by promoting active breaks and eyestrain treatment. This easy-to-use digital tool allows each worker to focus on areas of their choice via personalised, easy exercises that can be performed in the workplace.Trial registration numberNCT02350244; Pre-results.

Can experience modulate handler responses to boxes designed to decrease musculoskeletal load?

Biomechanical load during the handling of commercial (cardboard box with and without cut out) and non-commercial boxes (cardboard box with a retreat on the bottom edges), on experienced compared to inexperienced subjects was evaluated. Thirty-seven inexperienced and 21 experienced workers handled all boxes at shoulder and ground levels. Biomechanical load on upper limb was investigated through posture and electromyography (EMG) recordings. Comfort and effort were assessed immediately after each handling. In general, experienced workers had low range of motion. On the other hand, EMG was similar between both groups, except when non-commercial boxes were handled in non-favourable heights. Comfort was higher when a non-commercial box was handled versus a commercial one, regardless of the group. Both groups had a lower biomechanical load when handling the non-commercial boxes compared to the commercial ones. However, experienced workers did not have the same advantage as inexperienced subjects when handling those new boxes.Practitioner Summary: Box designs favouring intuitive hand coupling and more efficient postures have potential to reduce the risk of upper-limb musculoskeletal disorders in inexperienced subjects. However, ergonomist has to deal with workers on different levels of experience. Results of this study can support the development of effective recommendations for the working context.

A longitudinal study of neck and upper limb musculoskeletal disorders and alternative measures of vibration exposure

To investigate the exposure-response relationships between alternative frequency weightings of hand-transmitted vibration (HTV) and neck and upper limb musculoskeletal disorders (MSDs) in a cohort of HTV workers. In a three-year longitudinal study, the occurrence of neck and upper limb MSDs was investigated in 249 HTV workers and 138 control men. In the HTV workers, MSDs were related to measures of daily vibration exposure expressed in terms of 8-h energy-equivalent frequency-weighted acceleration magnitude [A(8)]. To calculate A(8), the acceleration magnitudes of vibration were weighted by means of four alternative frequency weightings of HTV. The associations between MSDs, individual characteristics, physical work load other than vibration, and psychological strain were also investigated. The occurrence of upper limb MSDs was greater in the HTV workers than in the controls. After adjustment for potential confounders, the occurrence of elbow/forearm and wrist/hand MSDs increased with the increase in vibration exposure. A measure of model selection did not reveal any substantial difference in the performance of the alternative frequency weightings of HTV for the prediction of neck and upper limb MSDs. In the study population, age, hard physical work load, and poor psychological well-being were associated with both neck and upper limb MSDs. In this study, there was evidence for significant exposure-response relationships between HTV exposure and MSDs in the distal sites of the upper limbs. There were no differences in the prediction of neck and upper limb MSDs between measures of daily vibration exposure calculated with alternative frequency weightings of acceleration magnitude.

Snap-fits and upper limb functional limitations in German automotive workers.

The use of snap-fit fasteners in automotive assembly has increased in the last 10 years. Their impact on musculoskeletal function of the upper limbs in assembly workers is not well described. To investigate the association between snap-fit assembly and upper limb functional limitations (ULFLs) in workers after a large-scale expansion of snap-fit assembly by a German automotive company. Cross-sectional data on blue-collar production workers' exposure to snap-fit assembly and ULFLs were collected from medical check-ups and company registers. The association between duration of snap-fit assembly and ULFLs, and the dose-response relationship between the two were analysed using logistic regression, adjusted for body mass index, gender and employment duration before snap-fit exposure. The study group included 10722 workers. Within the company, 8.4, 6.9 and 10.3% were exposed to snap-fit 1-12, 13-24 and ≥25 months, respectively. After adjusting for confounders, snap-fit exposure for 1-12 months [odds ratio (OR) = 1.59, 95% confidence interval (CI) 0.88-2.88] and 13-24 months (OR = 1.48, 95% CI 0.76-2.88) was not statistically significantly associated with ULFLs compared with an unexposed group. However, exposure to ≥25 months of snap-fit assembly was statistically significant associated with ULFLs showing >2-fold risk (OR = 2.44, 95% CI 1.52-3.92). No clear dose-response relationship was found. Our study suggests a negative long-term impact from snap-fit assembly on workers' upper limb function. Company physicians should be vigilant for signs of upper limb musculoskeletal disorders among workers exposed to snap-fit assembly.

Carpal Tunnel Syndrome and Food Manual Labor: Case Report and Compensation Issues

Aims: We report a case of bilateral carpal tunnel syndrome (CTS) in a patient who had been working with repetitive tasks for almost thirty years on his own business as pizza maker in a small restaurant. Food production outside the industry of food processing is often neglected in assessing biomechanical overload as an occupational risk for upper limb musculoskeletal disorders. Presentation of Case: A 54-year old male reported a progressive history of pain and numbness in the thumb and first three fingers of both hands, including dysaesthesia and nocturnal waking. Main factors influencing the risk such as frequency of repetitive movement, strain, posture, pauses, complementary risk factors are described. On site mini-check list Occupational Repetitive Actions (OCRA) assessed 40/50 technical actions per minute with peak acceleration related to customers’ demand and showed a middle-high risk with score 20. Discussion and Conclusion: Criteria used for determining eligibility for compensation are not uniform and according to regulations of a single country may cover different aspects of physiological impairment, work disability, healthcare costs, loss of income and professional retraining. This case highlights the importance of using more easily applicable tools for risk assessment that can be crucial for definition and determination of causation.