Evidence of rotator cuff disease after breast cancer treatment: scapular kinematics of post-mastectomy and post-reconstruction breast cancer survivors.

BACKGROUND: Breast cancer survivors may be at risk of experiencing rotator cuff disease after treatment. Biomechanical alterations following surgery potentially predispose survivors to develop this disorder. OBJECTIVE: To examine scapular kinematics in breast cancer survivors with and without impingement pain during an overhead reach task. DESIGN: A cross-sectional study. METHODS: Three surgery groups were included: non-cancer controls, mastectomy-only survivors and post-reconstruction survivors. Breast cancer survivor groups were also categorized by the presence of impingement pain. Scapular motion was tracked during an overhead reach task, performed separately by both arms. Maximum scapular internal rotation, upward rotation and tilt were calculated. Two-way analyses of variance with interactions (p < .05) were used to test the effects of group (control, mastectomy-only, reconstruction) and impingement pain (pain, no pain) on each variable within a (left/right) side. RESULTS: Scapular kinematics varied with the group by pain interaction. On the right side, the mastectomy-pain group had reduced upward rotation, while the reconstruction-pain group had higher upward rotation (mastectomy-only: 22.9° vs. reconstruction: 31.2°). On the left side, the mastectomy-pain group had higher internal rotation, while the reconstruction-pain group had reduced internal rotation (mastectomy-only: 45.1° vs. reconstruction: 39.3°). However, time since surgery was longer in the mastectomy-pain group than reconstruction-pain group, suggesting there may be a temporal component to kinematic compensations. CONCLUSIONS: There are kinematic alterations in breast cancer survivors that may promote future development of rotator cuff disease. Compensations may begin as protective and progress to more harmful alterations with time.KEY MESSAGESScapular kinematics varied with surgery and pain interaction: upward rotation was lower and internal rotation higher in mastectomy-pain group, while upward rotation was higher and internal rotation lower in reconstruction-pain group.Kinematics alterations may also be associated with time since surgery, as the mastectomy-pain group had longer time since surgery than the reconstruction-pain group.Kinematic alterations may transition from protective to harmful over time.In-depth analyses by reconstruction type are needed to determine surgery-specific effects on kinematics and their potential impact on the development of rotator cuff disease.

Ergonomic assessment of veterinarians during performance of bovine reproductive examinations.

OBJECTIVE: To identify and quantify potential ergonomic hazards associated with routine reproductive examinations of cattle. SAMPLE: 7 bovine veterinarians. PROCEDURES: Each veterinarian was observed and videotaped during 2 bovine reproductive examination appointments. During each appointment, a force-matching protocol was used to estimate the entry force used by the veterinarian to insert an arm into a cow's rectum. Veterinarian posture and repetitive movements and the work environment were assessed and quantified during review of the video recordings. Descriptive data were generated. RESULTS: Of the 14 appointments observed, 9 and 5 involved examination of beef and dairy cows, respectively. For all veterinarians, an arm inclination ≥ 60° was observed during most reproductive examinations. The number of examinations performed per hour ranged from 19.1 to 116.8. The estimated entry force ranged from 121 to 349 N. During all 9 appointments involving beef cows, the veterinarian participated in other tasks (eg, operating overhead levers, opening gates, or assisting with cattle handling) that represented ergonomic hazards. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirmed that reproductive examination of cattle exposes veterinarians to various ergonomic hazards involving awkward positions and repetitive and forceful exertions that can contribute to musculoskeletal discomfort and injury, particularly of the upper extremities (neck, shoulders, upper back, arms, elbows, wrists, and hands). Veterinarians frequently participated in other tasks during reproductive examination appointments that exposed them to additional ergonomic hazards. Risk mitigation strategies should prioritize minimizing exposure of veterinarians to tasks not directly associated with the reproductive examination procedure to decrease their overall ergonomic hazard burden.

A randomized controlled trial investigating effects of an individualized pedometer driven walking program on chronic low back pain.

BACKGROUND: Walking is an easily prescribed physical activity for people with low back pain (LBP). However, the evidence for its effectiveness to improve pain and disability levels for people with chronic low back pain (CLBP) within a community setting has not been evaluated. This study evaluates the effectiveness of a clinician guided, pedometer-driven, walking intervention for increasing physical activity and improving clinical outcomes compared to education and advice. METHODS: Randomized controlled trial recruiting N = 174 adults with CLBP. Participants were randomly allocated into either a standardized care group (SG) or pedometer based walking group (WG) using minimization allocation with a 2:1 ratio to the WG. Prior to randomization all participants were given a standard package of education and advice regarding self-management and the benefits of staying active. Following randomization the WG undertook a physiotherapist guided pedometer-driven walking program for 12 weeks. This was individually tailored by weekly negotiation of daily step targets. Main outcome was the Oswestry Disability Index (ODI) recorded at baseline, 12 weeks, 6 and 12 months. Other outcomes included, numeric pain rating, International Physical Activity Questionnaire (IPAQ), Fear-Avoidance Beliefs Questionnaire (FABQ), Back Beliefs questionnaire (BBQ), Physical Activity Self-efficacy Scale, and EQ-5D-5L quality of life estimate. RESULTS: N = 138 (79%) participants completed all outcome measures at 12 weeks reducing to N = 96 (55%) at 12 months. Both observed and intention to treat analysis did not show any statistically significant difference in ODI change score between the WG and the SG at all post-intervention time points. There were also no significant between group differences for change scores in all secondary outcome measures. Post hoc sensitivity analyses revealed moderately disabled participants (baseline ODI ≥ 21.0) demonstrated a greater reduction in mean ODI scores at 12 months in the WG compared to SG, while WG participants with a daily baseline step count < 7500 steps demonstrated a greater reduction in mean ODI scores at 12 weeks. CONCLUSIONS: Overall, we found no significant difference in change of levels of (ODI) disability between the SG and WG following the walking intervention. However, ODI responses to a walking program for those with moderate levels of baseline disability and those with low baseline step count offer a potential future focus for continued research into the benefit of walking as a management strategy for chronic LBP. TRIAL REGISTRATION: United States National Institutes of Health Clinical Trails registry (http://ClinicalTrials.gov/) No. NCT02284958 (27/10/2014).

Risk factors associated with work-preventing musculoskeletal discomfort in the upper extremities of bovine practitioners.

OBJECTIVE: To identify risk factors associated with work-preventing musculoskeletal discomfort (MSKD) in the upper extremities (defined as neck, shoulders, upper back, arms, elbows, wrists, and hands) of bovine practitioners. SAMPLE: 116 members of the Western Canadian Association of Bovine Practitioners. PROCEDURES: Data from a previously described cross-sectional survey of western Canadian bovine practitioners underwent further analysis. The survey, developed to glean information about MSKD in bovine practitioners, was a modified standardized Nordic questionnaire that included questions regarding personal and work characteristics and incidence and location of MSKD during the preceding 12 months along with perceptions about most physically demanding tasks. Logistic regression was used to identify factors associated with work-preventing upper extremity MSKD. RESULTS: 18 of 116 (15.5%) respondents indicated they had experienced work-preventing upper extremity MSKD during the preceding 12 months. The final multivariable regression model indicated that practice type (mixed animal vs primarily [> 50%] bovine; OR, 3.20; 95% CI, 0.96 to 10.67), practitioner height (OR, 0.93; 95% CI, 0.87 to 0.99), and number of veterinarians in the practice (OR, 1.32; 95% CI, 1.05 to 1.66) were significantly associated with the odds of work-preventing upper extremity MSKD. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that reproductive examination of cattle was not a significant risk factor for upper extremity MSKD in bovine practitioners. Further research into the effects of biomechanical, organizational, and psychosocial workplace factors on the development of MSKD in bovine practitioners is necessary to help inform prevention strategies to foster career longevity in this increasingly diverse practitioner group.

Measurement properties of instruments assessing permanent functional impairment of the spine: a systematic review protocol.

INTRODUCTION: Permanent functional impairment (PFI) of the spine is a rating system used by compensation authorities, such as workers compensation boards, to establish an appropriate level of financial compensation for persistent loss of function. Determination of PFI of the spine is commonly based on the assessment of spinal movement combined with other measures of physical and functional impairments; however, the reliability and validity of the measurement instruments used for these evaluations have yet to be established. The aim of this study is to systematically review and synthesise the literature concerning measurement properties of the various and different instruments used for assessing PFI of the spine. METHODS: Three conceptual groups of terms (1) PFI, (2) spinal disorder and (3) measurement properties will be combined to search Medline, EMBASE, CINAHL, Web of Science, Scopus, PEDro, OTSeeker and Health and Safety Science Abstracts. We will examine peer-reviewed, full-text articles over the full available date range. Two reviewers will independently screen citations (title, abstract and full text) and perform data extraction. Included studies will be appraised as to their methodological quality using the COnsensus-based Standards for the selection of health Measurement INstruments criteria. Findings will be summarised and presented descriptively, with meta-analysis pursued as appropriate. ETHICS AND DISSEMINATION: This review will summarise the current level of evidence of measurement properties of instruments used for assessing PFI of the spine. Findings of this review may be applicable to clinicians, policy-makers, workers' compensation boards, other insurers and health and safety organisations. The findings will likely provide a foundation and direction for future research priorities for assessing spinal PFI. PROSPERO REGISTRATION NUMBER: CRD42017060390.

Predicting Whole-Body Vibration Exposure in Canadian Prairie Farmers.

Direct workplace whole-body vibration exposure assessment provides ecological validity for evaluating health risk in epidemiological studies, yet it is complex and expensive in practical applications. Exposure prediction modeling could be a cost-efficient alternative to directly assessing occupational vibration exposures. The objective of this study was to model directly measured whole-body vibration exposures with predictors from machinery, farm, and self-reported characteristics among Canadian prairies farmers. As per ISO 2631-1, whole-body vibration data were measured on the seat surface at three axes (x, y, z), then summarized into vector sums of the root-mean-squared (RMS) acceleration and the vibration dose value (VDV). All candidate predictors were obtained via questionnaires and onsite observations. A total of 87 whole-body vibration measurements were collected from 40 male farm workers located at 21 central Saskatchewan farms. Using log-transformed RMS and time-standardized VDV outcomes, modeling started from the bivariate analysis where predictors with P-values < 0.2 were considered eligible for multivariate analysis. With random effects of 'farm' and 'farmer', a series of mixed-effects models were constructed through the manual backward elimination method. Final models were internally validated by 1000 bootstrapped samples. The RMS model explained 47.7% of the variance in the directly measured RMS vector sum, with 42.7% obtained from five predictors of 'horsepower', 'transmission', 'vehicle year', 'jerk/jolt frequency', and 'seat bottom-out frequency', while the VDV model explained 19.5% of the variance in the directly measured VDV vector sum, with 11.6% described by the same five predictors as the RMS model. Predictive ability of the RMS model among 1000 bootstrapped samples can be anticipated to range from 14.3 to 69.1%, which may be considered adequate as exposure assessment tool for uses of epidemiological studies. The percentage of variance explained ranged from 0 to 40.5% for the VDV model, which is not robust and therefore likely not appropriate for use in survey-based exposure prediction. Whole-body vibration exposure modeling remains valuable, but is challenging in farming; the described model variance may increase with a more comprehensive list of candidate variables collected and quantified at machinery, farm, and farmer level. Predictors identified in the current and future models may provide a better understanding of how whole-body vibration exposure is modified, guide farmer's future decision on updating equipment, and allow for the development and initiation of interventions.

Recruitment for Occupational Research: Using Injured Workers as the Point of Entry into Workplaces.

OBJECTIVE: To investigate the feasibility, costs and sample representativeness of a recruitment method that used workers with back injuries as the point of entry into diverse working environments. METHODS: Workers' compensation claims were used to randomly sample workers from five heavy industries and to recruit their employers for ergonomic assessments of the injured worker and up to 2 co-workers. RESULTS: The final study sample included 54 workers from the workers' compensation registry and 72 co-workers. This sample of 126 workers was based on an initial random sample of 822 workers with a compensation claim, or a ratio of 1 recruited worker to approximately 7 sampled workers. The average recruitment cost was CND$262/injured worker and CND$240/participating worksite including co-workers. The sample was representative of the heavy industry workforce, and was successful in recruiting the self-employed (8.2%), workers from small employers (<20 workers, 38.7%), and workers from diverse working environments (49 worksites, 29 worksite types, and 51 occupations). CONCLUSIONS: The recruitment rate was low but the cost per participant reasonable and the sample representative of workers in small worksites. Small worksites represent a significant portion of the workforce but are typically underrepresented in occupational research despite having distinct working conditions, exposures and health risks worthy of investigation.

Optimising sampling strategies: components of low-back EMG variability in five heavy industries.

BACKGROUND: Direct/ measurement of work activities is costly, so researchers need to distribute resources efficiently to elucidate the relationships between exposures and back injury. METHODS: This study used data from full-shift electromyography (EMG; N=133) to develop three exposure metrics: mean, 90th percentile and cumulative EMG. For each metric, the components of variance were calculated between- and within-subject, and between-group for four different grouping schemes: grouping by industry (construction, forestry, transportation, warehousing and wood products), by company, by job and by quintiles based on exposures ranked by jobs within industries. Attenuation and precision of simulated exposure-response relationships were calculated for each grouping scheme to determine efficient sampling strategies. RESULTS: As expected, grouping based on exposure quintiles had the highest between-group variances and lowest attenuation, demonstrating the lowest possible attenuation with this data. CONCLUSION: There is potential for grouping schemes to reduce attenuation, but precision losses should be considered and whenever possible empirical data should be employed to select potential exposure grouping schemes.

How long is long enough? Evaluating sampling durations for low back EMG assessment.

Few ergonomic measurement tools explicitly state when and how to sample exposures. Traditional ergonomic sampling has used short, task-based or worst-case measurements, but these may misrepresent exposures, since they neglect the temporal variations throughout the workday. Understanding the representativeness of data from shorter measurement durations compared with full-shift measurements allows for optimization of measurements resources. This study compared a variety of low back electromyography (EMG) exposure metrics measured over a full-shift with the same metrics sampled over shorter durations to identify whether shorter durations provide representative measures of exposure. Portable EMG devices were used to measure low back EMG for 138 full work shifts in a range of jobs in heavy industry. Using a random start time, each full shift of data was resampled for 4 hr, 2 hr, 1 hr, 10 min, and 2 min. Exposure metrics from each duration were compared with the full shift using absolute and percent error, bias, and limits of agreement. Comparisons between one full shift and two full shifts were made for the subset of 35 workers with two measured workdays. Compared with full-shift data, bias is very low at all sampling durations. However, as sampling durations decreased from a full-shift to a few min, the absolute error, percentage error, and limits of agreement for exposure estimates show more deviation from full-day estimates. Estimates of mean and 90th percentile exposure averaged 8% error for 4-hr durations and 14% error for 2-hr durations. The errors for 4-and 2-hr measurement durations may be acceptable for many applications, particularly if the trade-off is measuring more subjects. Sampling durations of 1 hr or less seem likely to produce very large errors over all exposure metrics, particularly for the range and peak exposures. Depending on the purpose of measurement and the detail required, 4 hr or even 2 hr appears to be long enough to reasonably estimate full-shift exposure.