Radiographic findings in patients suspected of subacromial impingement syndrome: prevalence and reliability

OBJECTIVE

Aims were to (i) report prevalence and (ii) evaluate reliability of the radiographic findings in examinations of patients suspected of subacromial impingement syndrome (SIS), performed before a patient's first consultation at orthopaedic department.

MATERIALS AND METHODS

This cross-sectional study examined radiographs from 850 patients, age 18 to 63 years, referred to orthopaedic clinic on suspicion of SIS. Prevalence (%) of radiographic findings were registered. Inter- and intrarater reliability was analysed using expected and observed agreement (%), kappa coefficients, Bland-Altman plots, or intraclass coefficients.

RESULTS

A total of 850 patients with a mean age of 48.2 years (SD = 8.8) were included. Prevalence of the radiographic findings was as follows: calcification 24.4%, Bigliani type III (hooked) acromion 15.8%, lateral/medial acromial spurs 11.1%/6.6%, acromioclavicular osteoarthritis 12.0%, and Bankart/Hill-Sachs lesions 7.1%. Inter- and intrarater Kappa values for most radiographic findings ranged between 0.40 and 0.89; highest values for the presence of calcification (0.85 and 0.89) and acromion type (0.63 and 0.66). The inter- and intrarater intraclass coefficients ranged between 0.41 and 0.83; highest values for acromial tilt (0.79 and 0.83) and calcification area (0.69 and 0.81).

CONCLUSION

Calcification, Bigliani type III (hooked) acromion, and acromioclavicular osteoarthritis were prevalent findings among patients seen in orthopaedic departments on suspicion of SIS. Spurs and Bankart/Hill-Sachs lesions were less common. Optimal reliabilities were found for the presence of calcification, calcification area, and acromial tilt. Calcification qualities, acromion type, lateral spur, and acromioclavicular osteoarthritis showed suboptimal reliabilities. Newer architectural measures (acromion index and lateral acromial angle) performed well with respect to reliability.

Reducing Shoulder Complaints in Employees with High Occupational Shoulder Exposures: A Cluster-Randomised Controlled Study (The Shoulder-Café Study)

PURPOSE

To evaluate if a group-based Shoulder-Café intervention could reduce shoulder complaints more effectively than an individual-based control intervention in employees with shoulder complaints and high occupational shoulder exposures.

METHODS

A cluster-randomised controlled study of 109 participants from 60 companies in Central Denmark Region. Companies were randomised and allocated to either Shoulder-Café or control intervention. Participants in both interventions received a pamphlet on home-based shoulder exercises and a pamphlet with general information on reducing occupational shoulder exposures. They also had their occupational shoulder exposures assessed. Shoulder-Café participants additionally received three café-meetings with casual discussion, clinical shoulder evaluation, education about shoulder anatomy and occupational shoulder exposures, supervised exercises, workplace-oriented counselling, and an optional workplace visit. The primary outcome measure was the Oxford Shoulder Score (OSS) at 6-month follow-up. Secondary outcome measures were the OSS at 12 months, Fear-Avoidance Beliefs Questionnaire - Physical Activity at 6 and 12 months, and Patients' Global Impression of Change at 6 months. The study also included seven supplementary outcome measures.

RESULTS

Both groups improved from baseline to 6 months with respect to the primary outcome (P < 0.01). No group differences were found for the primary outcome (mean difference (MD) [95% confidence interval]: 0.3 [- 1.6; 2.2]) or secondary outcomes. The supplementary outcomes "felt informed about handling shoulder complaints" and "felt informed about reducing occupational exposures" at 6 months, and "Patients' Global Impression of Change" and "overall satisfaction" at 12 months favoured the Shoulder-Café intervention.

CONCLUSION

The Shoulder-Café intervention did not reduce shoulder complaints more effectively than the control intervention.

TRIAL REGISTRATION

The trial was registered at Clinicaltrials.gov on 19 May 2017 (ID: NCT03159910).

Return to Work After Surgery For Trapeziometacarpal Joint Osteoarthritis in Relation to Occupational Hand Force Requirements

PURPOSE

This study evaluated the hypothesis that higher occupational hand force requirements are related to slower return to work (RTW) after surgery for trapeziometacarpal joint osteoarthritis.

METHODS

Patients treated surgically for trapeziometacarpal joint osteoarthritis from 2001 to 2017 were identified in the Danish National Patient Register. Sustainable RTW (sRTW) was defined as the first period of 4 consecutive weeks without health-related public transfer payments, according to the Danish National Register on Public Transfer Payments. Occupational codes from the Danish Employment Classification Module were linked to a hand-arm job exposure matrix to obtain occupational hand force requirements for each patient. Cox regression models were used to analyze time until sRTW in relation to hand force requirements with adjustment for age, sex, type of surgery, preoperative sick leave, and calendar year of surgery.

RESULTS

The study included 2,090 patients. Within 104 weeks, 91% sustainably returned to work. The percentage of individuals in the subgroups that did not RTW was 8% of low-force- and medium-force-exposed patients and 14% of high-force-exposed patients. Medium and high occupational hand force requirements were associated with slower sRTW. The adjusted hazard ratio for sRTW was 0.84 (95% confidence interval, 0.74-0.95) for medium and 0.59 (95% confidence interval, 0.50-0.68) for high compared with low hand force requirements. Among patients who returned to work, patients with medium and high hand force requirements had median periods until sRTW of 16 and 18 weeks, respectively, compared with 10 weeks among patients with low hand force requirements.

CONCLUSIONS

The prognosis regarding RTW after surgery for trapeziometacarpal joint osteoarthritis is generally good, but patients with higher occupational hand force requirements can expect slower RTW.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Agreement between an expert-rated mini job exposure matrix of occupational biomechanical exposures to the lower body and technical measurements or observation: a method comparison study

OBJECTIVES

Investigating the agreement between an expert-rated mini job exposure matrix (JEM) of lower body exposures and technical measurements of worktime spent standing/walking and observation-based estimates of time spent kneeling/squatting and total load lifted per workday.

METHODS

We chose 16 job titles from the 121 job groups in the lower body JEM and included them in the mini JEM. New expert ratings for the mini JEM were performed by the same five occupational physicians who performed the ratings for the lower body JEM. For each job title and type of exposure, the exposure estimates were a mean of the five independent ratings. Technical measurements of standing/walking for all 16 job titles, and for 8 job titles workplace observations were performed of kneeling/squatting and total load lifted per workday. Data were collected from September to December 2015 and supplemented by data from the NOMAD and DPhacto studies collected between 2011 and 2013. All data were collected in Denmark. Agreement between expert-based and measured/observed lower body exposures by job titles was evaluated using Spearman's rank correlation, Bland-Altman plots evaluated systematic deviations and limits of agreement (LoA).

RESULTS

Standing/walking showed a rank correlation of 0.55, kneeling/squatting 0.83 and total load lifted per workday 0.71. The mini JEM estimates did not systematically deviate from the technical measurements/observations for time spent standing/walking (mean difference 0.20 hours/workday, LoA -1.63, 2.03 hours/workday) and kneeling/squatting (mean difference -0.35 hours/workday, LoA -1.21, 0.51 hours/workday). For total load lifted per workday, the mini JEM systematically overestimated the exposures compared with the observations (mean difference -909 kg/workday, LoA -3000, 1147 kg/workday).

CONCLUSIONS

There was moderate to very high agreement between an expert-rated mini JEM of standing/walking, kneeling/squatting, and lifting exposures and corresponding technical measurements/observations. This method comparison study supports the use of the expert-based lower body JEM in large-scale occupational epidemiological studies.

Associations between single and combined occupational mechanical exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study

OBJECTIVE

This study aimed to evaluate whether the risk of surgery for subacromial impingement syndrome (SIS) increases with the number of combined occupational mechanical exposures compared with single exposure.

METHODS

We reanalyzed data from a register-based cohort study of the entire Danish working population (N=2 374 403) with 14 118 events of surgery for SIS (2003-2008). Exposure information in 10-year windows was obtained by combining occupational codes with a job exposure matrix. For single and combined mechanical exposures, we created three exposure variables of the number of years with specific exposure intensities with or without co-existing mechanical exposures. We used logistic regression as survival analysis.

RESULTS

We found exposure-response relations for duration and intensity of each single mechanical exposure except for repetition. The single effect of arm elevation >90º reached a maximum adjusted odds ratio (OR_adj) of 1.7 [95% confidence interval (CI) 1.5-2.0], which increased to 1.8 (95% CI 1.5-2.0), 2.0 (95% CI 1.9-2.2), and 2.2 (95% CI 2.0-2.5) when combined with repetition, force, and both. When combining repetition with arm elevation >90º, force, and both, OR_adj increased from 1.5 (95% CI 1.3-1.8) to 2.1 (95% CI 1.8-2.4), 2.5 (95% CI 2.4-2.9), and 2.7 (95% CI 2.4-3.0). For force, OR_adj increased from 2.5 (95% CI 2.1-2.9) to 2.6 (95% CI 2.3-2.8), 2.8 (95% CI 2.4-3.2), and 3.0 (95% CI 2.6-3.4).

CONCLUSION

We found an increased risk of surgery for SIS with the number of combined exposures; the risk was especially pronounced when the combined exposures included force.

Revision rates of trapeziometacarpal total joint arthroplasty in relation to occupational hand force requirements

The purpose was to determine revision rates after trapeziometacarpal total joint arthroplasty in working age patients, hypothesizing that higher occupational hand force requirements lead to higher revision rates. We conducted a follow-up study of patients operated 2003-2015. Self-reported job titles at the time of primary surgery were linked with a job exposure matrix to estimate occupational hand force requirements. Time until revision was analysed using Cox regression. The study comprised 222 patients aged 39-65 years (mean 55, SD 6), including 133 patients in the labour market. The median follow-up period was 5 years (interquartile range 4-7) and the overall revision rate was 5/100 person-years. For high versus low occupational hand force requirements, the hazard ratio was 1.5 (95% confidence interval 0.5-4.4). For patients outside the labour market, the hazard ratio was 2.3 (0.9-5.6). Our results did not indicate large effects of high occupational hand force requirements on revision rates.Level of evidence: IV.

Surgery for trapeziometacarpal osteoarthritis in relation to cumulative occupational hand force requirements: a Danish nationwide cohort study

OBJECTIVES

To evaluate if higher cumulative occupational hand force requirements are associated with higher risks of surgery for trapeziometacarpal osteoarthritis and with surgery earlier in life.

METHODS

The study was based on Danish national registers. Among all persons born in Denmark 1931 to 1990, we included those who had been employed for at least 5 years since 1991 by the end of 2000, or later when this employment criterion was reached, up until the end of 2016. Cumulative exposure estimates for 10-year time windows (force-years) were assessed by combining individual year-by-year information on occupational codes with an expert based hand-arm job exposure matrix. First-time events of surgery for trapeziometacarpal osteoarthritis 2001 to 2017 constituted the outcome. Surgery rates were analysed by a logistic regression technique equivalent to discrete survival analysis using a 1-year lag. We also calculated rate advancement periods.

RESULTS

A total of 2 860 448 persons contributed with around 48 million person-years of follow-up, during which 3977 cases appeared (821 among men and 3156 among women). Compared with <5 force-years, the adjusted OR (OR_adj) for ≥5 to <10 force-years was 1.39 (95% CI 1.14 to 1.68) and for ≥10 to 30 force-years 1.47 (95% CI 1.26 to 1.71) among men and 1.64 (95% CI 1.50 to 1.78) and 1.29 (95% CI 1.16 to 1.43) among women. The sex combined OR_adj were 1.59 (95% CI 1.47 to 1.72) and 1.36 (95% CI 1.25 to 1.48). Among the exposed, surgery was advanced by 3 to 7 years.

CONCLUSION

Medium/high cumulative hand force requirements were associated with elevated hazard rates of surgery for trapeziometacarpal osteoarthritis and advanced the time of surgery by several years.

Reducing shoulder complaints in employees with high occupational shoulder exposures: study protocol for a cluster-randomised controlled study (The Shoulder-Café Study)

Background

In Denmark, exercise therapy in combination with work modification is the first-choice treatment for persons with shoulder complaints and high occupational shoulder exposures. To obtain this treatment they must visit several healthcare providers, which makes usual care fragmented and uncoordinated. Therefore, we developed a new intervention which unifies the expertise that is needed. The main hypotheses are that a group-based Shoulder-Café intervention will more effectively reduce (1) shoulder complaints and (2) occupational shoulder exposures than an individual-based Shoulder-Guidance intervention (active control – enhanced usual care).

Methods

A cluster-randomised trial is conducted including 120 employees with high occupational shoulder exposures. Companies (clusters) are randomised to either Shoulder-Café or Shoulder-Guidance with a 1:1 allocation ratio. Participants are 18–65 years old and have an Oxford Shoulder Score (OSS) ≤ 40. Both interventions include a home-based shoulder-exercise programme, assessment of shoulder exposures by technical measurements and self-report, and general information on how to reduce shoulder exposures. The Shoulder-Café course also includes three café meetings with physiotherapist-supervised exercises, clinical shoulder evaluation, education on shoulder anatomy, workplace-orientated counselling, and an opportunity for a workplace visit by a health and safety consultant. The primary outcomes are the OSS at 6-month follow-up (hypothesis I), and the mean number of min/day with the arm elevated > 60° shortly after the end of the intervention (hypothesis II). We will use a mixed-model analysis that allows for company clustering, and data will be analysed according to the intention-to-treat principle.

Discussion

Persons with shoulder complaints and high occupational shoulder exposures are an obvious target group for secondary prevention efforts. We developed the Shoulder-Café to reduce shoulder complaints and shoulder exposures while unifying the expertise that is needed to evaluate and treat shoulder complaints. If the intervention is effective, it would warrant widespread implementation.

Trial registration

Clinicaltrials.gov, ID: NCT03159910. Registered on 18 May 2017

Persistent postoperative pain after inguinal hernia repair in relation to occupational lifting and standing/walking: a 6-month follow-up study

OBJECTIVES

This study aims to evaluate the risk of persistent postoperative pain after inguinal hernia repair in relation to occupational lifting and standing/walking.

METHODS

We conducted a 6-month follow-up study that included all men with an inguinal hernia repair registered in the Danish Hernia Database from 1 January 2015 to 31 October 2016, who were born from 1 October 1949 to 1 October 1998, and who were alive, living in Denmark, and active in the labour market in the week before surgery. Members of the cohort received a questionnaire 6 months after surgery. Exposure estimates were allocated by combining self reported job titles with a job exposure matrix. Prevalence ratios of persistent postoperative pain during activity ≥2 on a numerical rating scale (range 0-10) according to occupational lifting and standing/walking were estimated using Poisson regression.

RESULTS

Of 4817 eligible patients, 2609 (54%) returned the questionnaire and 2508 contributed to the analyses. A total of 473 men (18.9%) reported persistent postoperative pain. In the group lifting >1000 to 6125 kg/day, the prevalence was 26.8% compared with 17.5% in the minimally exposed group; adjusted prevalence ratio: 1.44 (95% CI 1.16 to 1.79). For standing/walking >6 hours/day, the prevalence was 23.6% compared with 17.0% in the group standing <4 hours/day; adjusted prevalence ratio: 1.18 (95% CI 0.92 to 1.50).

CONCLUSIONS

The risk of persistent postoperative pain after inguinal hernia repair was elevated among men with occupational lifting exposures >1000 kg/day. This finding suggests a preventive potential.

Disability and return to work after MRI on suspicion of scaphoid fracture: Influence of MRI pathology and occupational mechanical exposures

Objectives

We aimed to determine the prognosis after early MRI on clinical suspicion of scaphoid fracture, hypothesising that MRI pathology is associated with more disability and that MRI pathology and high occupational mechanical hand-arm exposures are associated with slower return to work (RTW).

Methods

We conducted a follow-up study of a cohort of 469 patients, who were scanned in the period 2006 to 2010. The respondents constituted our cohort for disability analysis and the subset that was in the labour market at the time of the trauma constituted our sub-cohort for RTW analysis. Questionnaires included disability scores, job title, and lifestyle factors. Job titles were linked with a job exposure matrix to estimate occupational exposures. Register information was obtained on time until RTW. We used logistic regression analysis of disability and Cox regression analysis of time until RTW.

Results

The proportion that responded was 53% (249/469) for the disability analysis and 59% (125/212) for the RTW analysis. The mean age at follow up was 43.5 years, the mean time since trauma was 4.8 years, 53% had injury of the dominant hand, and 54% had MRI pathology. Men constituted 43% of the cohort and 56% of the sub-cohort. MRI pathology was not associated with more disability [e.g., for a 'Disabilities of the Arm Shoulder and Hand'-score ≥20 the odds ratio was 0.58 (95% confidence interval 0.26–1.17)]. Patients without MRI pathology and with low occupational exposures were off work for an average of four weeks. Patients with MRI pathology or high occupational exposures were off work for twice as long time.

Conclusion

MRI pathology was not associated with more disability. For patients, who were in the labour market at the time of the trauma, MRI pathology and high occupational mechanical hand-arm exposures were associated with slower RTW.

Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows

Objectives

We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate if exposure to hand-arm vibration (HAV) is an independent risk factor.

Methods

We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003–2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register-based occupational codes (1993–2007) to a general population job exposure matrix to obtain year-by-year exposure intensities on measurement scales for force, upper arm elevation >90° and repetition and expert rated intensities of exposure to HAV. For 10-year exposure time windows, we calculated the duration of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures.

Results

We found indications of safe exposure intensities for repetition (median angular velocity <45°/s), while force exertion ≥10% of maximal voluntary electrical activity and upper arm elevation >90° >2 min/day implied an increased risk reaching ORs of 1.7 and 1.5 after 10 years at low intensities. No associations were found for HAV.

Conclusions

We found indications of safe exposure intensities for repetition. Any intensities of force and upper arm elevation >90° above minimal implied an increased risk across 10-year exposure time windows. No independent associations were found for HAV.

Inguinal hernia repair among men in relation to occupational mechanical exposures and lifestyle factors: a longitudinal study

OBJECTIVES

To evaluate exposure-response relationships between occupational mechanical exposures and first-time lateral and medial inguinal hernia repair and effects of lifestyle factors. To estimate if occupational mechanical exposures advance the repairs.

METHODS

This longitudinal study was based on a cohort of men aged 18-65 years with questionnaire data from the Musculoskeletal Research Database at the Danish Ramazzini Centre. We estimated occupational mechanical exposures using a job exposure matrix. First-time inguinal hernia repairs from 1998 to 2014 were identified in the Danish Hernia Database. We used Cox regression analyses and calculated excess fractions among the exposed and rate advancement periods (RAPs).

RESULTS

Among 17 967 men, we identified 382 lateral and 314 medial repairs. The risk of lateral repairs increased with time spent standing/walking with an HR of 1.45 (95% CI 1.12 to 1.88) for ≥6 hours/day versus <4 hours/day, corresponding to an excess fraction of cases of 31% in the group with ≥6 hours/day. This group had a RAP of 6.7 (95% CI 2.6 to 10.8) years. Medial repairs were not associated with occupational mechanical exposures. A body mass index ≥30 kg/m² showed lower HRs for both repair types. Leisure-time physical activity and smoking status were not related to any of the outcomes.

CONCLUSIONS

Assuming a causal relationship, the results suggest that around 30% of all first-time lateral inguinal hernia repairs in the highest exposure category would be preventable if the time spent standing/walking could be reduced from ≥6 to <4 hours/day. The repairs might even be postponed by 6-7 years.

Reversible median nerve impairment after three weeks of repetitive work

Objectives The aim of this study was to evaluate the development of impaired median nerve function in relation to hand-intensive seasonal work. We hypothesized that at end-season, median nerve conduction would be impaired and then recover within weeks. Methods Using nerve conduction studies (NCS), we examined median nerve conduction before, during, and after engaging in 22 days of mink skinning. For a subgroup, we used goniometry and surface electromyography to characterize occupational mechanical exposures. Questionnaire information on symptoms, disability, and lifestyle factors was obtained. Results The study comprised 11 male mink skinners with normal median nerve conduction at pre-season (mean age 35.7 years, mean number of seasons with skinning 8.9 years). Mink skinning was characterized by a median angle of wrist flexion/extension of 16º extension, a median velocity of wrist flexion/extension of 22 °/s, and force exertions of 11% of maximal voluntary electrical activity. At end-season, mean distal motor latency (DML) had increased 0.41 ms (P<0.001), mean sensory nerve conduction velocity (SNCV) digit 2 had decreased 6.3 m/s (P=0.004), and mean SNCV digit 3 had decreased 6.2 m/s (P=0.01); 9 mink skinners had decreases in nerve conduction, 5 fulfilled electrodiagnostic criteria and 4 fulfilled electrodiagnostic and clinical criteria (a positive Katz hand diagram) for carpal tunnel syndrome (CTS). Three to six weeks post-season, the changes had reverted to normal. Symptom and disability scores showed corresponding changes. Conclusions In this natural experiment, impaired median nerve conduction developed during 22 days of repetitive industrial work with moderate wrist postures and limited force exertion. Recovery occurred within 3-6 weeks post-season.

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.

The Use of Physiotherapy among Patients with Subacromial Impingement Syndrome: Impact of Sex, Socio-Demographic and Clinical Factors

Background

Physiotherapy with exercises is generally recommended in the treatment of patients with subacromial impingement syndrome (SIS).

Objective

We aimed to investigate the use of physiotherapy in patients with SIS in Danish hospital settings as part of initial non-surgical treatment and after SIS-related surgery and to evaluate to which extent sex, socio-demographic and clinical factors predict the use of physiotherapy.

Methods

Using national health registers, we identified 57,311 patients who had a first hospital contact with a diagnosis of ICD-10, groups M75.1–75.9, 1 July 2007 to 30 June 2011. Records of physiotherapy were extracted within 52 weeks after first contact (or until surgery), and for surgically treated patients within 26 weeks after surgery. Predictors of the use of physiotherapy after first contact and after surgery were analysed as time-to-event.

Results

Within 52 weeks after first contact, 43% of the patients had physiotherapy and 30% underwent surgery. Within 26 weeks after surgery, 80% had a record of physiotherapy. After first contact and after surgery, exercise was part of physiotherapy in 65% and 84% of the patients, respectively. A public hospital contact, physiotherapy before hospital contact, administrative region, female sex, a diagnosis of other or unspecified disorders (M75.8-M75.9), and surgical procedure predicted higher use of physiotherapy. Low education level predicted slightly lower use of physiotherapy after first contact, but not after surgery.

Conclusion

In patients with SIS in Danish hospital settings, physiotherapy was more often used after surgery than as part of initial non-surgical treatment. The use of physiotherapy was less common among men than women, whereas unequal use of physiotherapy in relation to education level was not noticeable. The use of physiotherapy with exercises in initial non-surgical treatment was relatively limited.

Proteomics perspectives in rotator cuff research: a systematic review of gene expression and protein composition in human tendinopathy

BACKGROUND

Rotator cuff tendinopathy including tears is a cause of significant morbidity. The molecular pathogenesis of the disorder is largely unknown. This review aimed to present an overview of the literature on gene expression and protein composition in human rotator cuff tendinopathy and other tendinopathies, and to evaluate perspectives of proteomics--the comprehensive study of protein composition--in tendon research.

MATERIALS AND METHODS

We conducted a systematic search of the literature published between 1 January 1990 and 18 December 2012 in PubMed, Embase, and Web of Science. We included studies on objectively quantified differential gene expression and/or protein composition in human rotator cuff tendinopathy and other tendinopathies as compared to control tissue.

RESULTS

We identified 2199 studies, of which 54 were included; 25 studies focussed on rotator cuff or biceps tendinopathy. Most of the included studies quantified prespecified mRNA molecules and proteins using polymerase chain reactions and immunoassays, respectively. There was a tendency towards an increase of collagen I (11 of 15 studies) and III (13 of 14), metalloproteinase (MMP)-1 (6 of 12), -9 (7 of 7), -13 (4 of 7), tissue inhibitor of metalloproteinase (TIMP)-1 (4 of 7), and vascular endothelial growth factor (4 of 7), and a decrease in MMP-3 (10 of 12). Fourteen proteomics studies of tendon tissues/cells failed inclusion, mostly because they were conducted in animals or in vitro.

CONCLUSIONS

Based on methods, which only allowed simultaneous quantification of a limited number of prespecified mRNA molecules or proteins, several proteins appeared to be differentially expressed/represented in rotator cuff tendinopathy and other tendinopathies. No proteomics studies fulfilled our inclusion criteria, although proteomics technologies may be a way to identify protein profiles (including non-prespecified proteins) that characterise specific tendon disorders or stages of tendinopathy. Thus, our results suggested an untapped potential for proteomics in tendon research.

Combined musculoskeletal pain in the upper and lower body: associations with occupational mechanical and psychosocial exposures

PURPOSE

Pain in more than one site is common in working populations. We aimed to characterise combined pain (pain in the upper and lower body) and to evaluate whether the prevalence of combined pain is positively related to combined occupational mechanical exposures to the upper and lower body and to high psychosocial job strain.

METHODS

This cross-sectional study was based on questionnaire data from the Musculoskeletal Research Database at the Danish Ramazzini Centre. The study included 14,081 men and 20,173 women. Occupational exposures were assessed by job exposure matrices. We analysed the prevalence of pain limited to the upper body, pain limited to the lower body, and combined pain in relation to occupational exposures using Poisson regression.

RESULTS

During the last year, 23.2 % of the men and 33.9 % of the women reported combined pain, which was characterised by somatisation, illness worrying, and low SF-36 scores. For men, the adjusted prevalence ratio for combined pain was 1.51 [95 % confidence interval (95 % CI) 1.40-1.64] in relation to exposures limited to the upper body and 2.24 (95 % CI 2.11-2.39) in relation to combined exposures. For women, the corresponding adjusted prevalence ratios were 1.56 (95 % CI 1.50-1.63) and 1.55 (95 % CI 1.50-1.61). High job strain was related to pain among men, only.

CONCLUSION

Combined pain may in part be explained by local effects of occupational mechanical exposures acting at more than one site.

Total hip replacement due to primary osteoarthritis in relation to cumulative occupational exposures and lifestyle factors: a nationwide nested case-control study

OBJECTIVE

To investigate the risk of total hip replacement (THR) due to primary osteoarthritis in relation to cumulative occupational mechanical exposures and lifestyle factors.

METHODS

Using register information, we identified first-time THR cases within the Danish working population in 2005-2006. For each case, 2 age- and sex-matched controls were drawn. Persons within 2,500 randomly selected case-control sets received a questionnaire about job history, weight at age 25 years, present weight and height, smoking, and sports activities at age 25 years. The job history was combined with a job exposure matrix. Cumulative exposure estimates were expressed according to the pack-year concept of smoking (e.g., cumulative lifting was expressed as ton-years). We used conditional logistic regression for statistical analyses.

RESULTS

In total, 1,776 case-control sets (71%) were available for analysis. The adjusted odds ratio (OR) for exposure to ≥20 ton-years was 1.35 (95% confidence interval [95% CI] 1.05-1.74) for men and 1.00 (95% CI 0.73-1.41) for women. Standing/walking and whole body vibration showed no associations. The adjusted OR for body mass index (BMI) ≥30 kg/m(2) at age 25 years was 2.44 (95% CI 1.38-4.32) for men and 5.12 (95% CI 2.30-11.39) for women. The corresponding adjusted ORs for an increase in BMI of ≥10 kg/m(2) since age 25 years were 2.16 (95% CI 1.25-3.70) and 2.46 (95% CI 1.47-4.13). Sports participation showed weak positive associations, while pack-years of smoking showed no associations.

CONCLUSION

The results indicated a modest increase in risk of THR in relation to cumulative lifting among men and an increased risk in relation to a high BMI at age 25 years and to a gain in BMI in both sexes.

Occupational mechanical exposures and reoperation after first-time inguinal hernia repair: a prognosis study in a male cohort

PURPOSE

The aim of this study was to evaluate exposure-response relationships between occupational mechanical exposures and risk of reoperation after inguinal hernia repair.

METHODS

Using register information, we identified all men born in Denmark 1938-1988, who had their first inguinal hernia repair 1998-2008, and who were 18-65 years old and active in the labour market at the time of surgery. The Danish Hernia Database provided information on repairs and reoperations. We used registered occupational codes and a job exposure matrix based on experts' ratings to estimate total load lifted per day, frequency of heavy lifting, and number of hours per day spent standing/walking. We also obtained register information on sickness absence. Multivariable Cox regression analysis was used.

RESULTS

The cohort comprised 34,822 patients. We did not reveal exposure-response relationships between occupational mechanical exposures and the hazard ratio (HR) of reoperation. The percentage of patients with >2 weeks of sickness absence within 8 weeks after surgery increased with total load lifted per day from 15 to 53%. Longer sickness absence was associated with an increased HR of reoperation, but within strata of sickness absence, we found no increase in the HR of reoperation with increasing exposures.

CONCLUSION

We did not find indications that the HR of reoperation was related to occupational mechanical exposures, even after accounting for a potential protective effect of sickness absence. Hence, the exposure-related prolonged duration of sickness absence could not be explained by exposure-related complications that led to reoperation.

Cross-neutralization studies with salmonid alphavirus subtype 1-6 strains: results with sera from experimental studies and natural infections

The serological reactivity between strains of each of the six currently genetically defined subtypes of salmonid alphavirus (SAV) was examined by comparison of homologous and heterologous virus neutralization titres on sera from experimentally infected fish. With the exception of the level of SAV subtype 6 neutralization by heterologous sera, good cross-neutralization was detected between all subtypes, albeit with variation in geometric mean titres when each subtype-specific serum set was tested against the panel of virus subtypes. A similar pattern was evident with field sera, except that heterologous neutralization of the SAV6 strain was more evident. In only 23% of available pairwise comparisons was the homologous titre recorded with an experimentally derived serum fourfold or greater than the heterologous titre, and in only two instances was this difference demonstrated in both directions. No virus strains consistently met the old serology-based criteria (Sub-committee on Inter-relationships Among Catalogued Alphaviruses) to be considered separate subtypes within an alphavirus species. Only when testing with an SAV subtype-2-specific monoclonal antibody was a major difference between homologous and heterologous neutralization capacity evident. These results provide new direct or indirect information in terms of SAV classification, vaccine efficacy and the selection and validation of reagents for serological and immunological diagnostic purposes.

Shoulder function and work disability after decompression surgery for subacromial impingement syndrome: a randomised controlled trial of physiotherapy exercises and occupational medical assistance

BACKGROUND

Surgery for subacromial impingement syndrome is often performed in working age and postoperative physiotherapy exercises are widely used to help restore function. A recent Danish study showed that 10% of a nationwide cohort of patients retired prematurely within two years after surgery. Few studies have compared effects of different postoperative exercise programmes on shoulder function, and no studies have evaluated workplace-oriented interventions to reduce postoperative work disability. This study aims to evaluate the effectiveness of physiotherapy exercises and occupational medical assistance compared with usual care in improving shoulder function and reducing postoperative work disability after arthroscopic subacromial decompression.

METHODS/DESIGN

The study is a mainly pragmatic multicentre randomised controlled trial. The trial is embedded in a cohort study of shoulder patients referred to public departments of orthopaedic surgery in Central Denmark Region. Patients aged ≥18-≤63 years, who still have shoulder symptoms 8-12 weeks after surgery, constitute the study population. Around 130 participants are allocated to: 1) physiotherapy exercises, 2) occupational medical assistance, 3) physiotherapy exercises and occupational medical assistance, and 4) usual care. Intervention manuals allow individual tailoring. Primary outcome measures include Oxford Shoulder Score and sickness absence due to symptoms from the operated shoulder. Randomisation is computerised with allocation concealment by randomly permuted block sizes. Statistical analyses will primarily be performed according to the intention-to-treat principle.

DISCUSSION

The paper presents the rationale, design, methods, and operational aspects of the Shoulder Intervention Project (SIP). SIP evaluates a new rehabilitation approach, where physiotherapy and occupational interventions are provided in continuity of surgical episodes of care. If successful, the project may serve as a model for rehabilitation of surgical shoulder patients.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN55768749.

An expert-based job exposure matrix for large scale epidemiologic studies of primary hip and knee osteoarthritis: the Lower Body JEM

BACKGROUND

When conducting large scale epidemiologic studies, it is a challenge to obtain quantitative exposure estimates, which do not rely on self-report where estimates may be influenced by symptoms and knowledge of disease status. In this study we developed a job exposure matrix (JEM) for use in population studies of the work-relatedness of hip and knee osteoarthritis.

METHODS

Based on all 2227 occupational titles in the Danish version of the International Standard Classification of Occupations (D-ISCO 88), we constructed 121 job groups comprising occupational titles with expected homogeneous exposure patterns in addition to a minimally exposed job group, which was not included in the JEM. The job groups were allocated the mean value of five experts' ratings of daily duration (hours/day) of standing/walking, kneeling/squatting, and whole-body vibration as well as total load lifted (kg/day), and frequency of lifting loads weighing ≥20 kg (times/day). Weighted kappa statistics were used to evaluate inter-rater agreement on rankings of the job groups for four of these exposures (whole-body vibration could not be evaluated due to few exposed job groups). Two external experts checked the face validity of the rankings of the mean values.

RESULTS

A JEM was constructed and English ISCO codes were provided where possible. The experts' ratings showed fair to moderate agreement with respect to rankings of the job groups (mean weighted kappa values between 0.36 and 0.49). The external experts agreed on 586 of the 605 rankings.

CONCLUSION

The Lower Body JEM based on experts' ratings was established. Experts agreed on rankings of the job groups, and rankings based on mean values were in accordance with the opinion of external experts.

Occupational lifting, fetal death and preterm birth: findings from the Danish National Birth Cohort using a job exposure matrix

Objective

We examined the association between occupational lifting during pregnancy and risk of fetal death and preterm birth using a job exposure matrix (JEM).

Methods

For 68,086 occupationally active women in the Danish National Birth Cohort, interview information on occupational lifting was collected around gestational week 16. We established a JEM based on information from women, who were still pregnant when interviewed. The JEM provided mean total loads lifted per day within homogeneous exposure groups as informed by job and industry codes. All women were assigned an exposure estimate from the JEM. We used Cox regression models with gestational age as underlying time variable and adjustment for covariates.

Results

We observed 2,717 fetal deaths and 3,128 preterm births within the study cohort. No exposure-response relation was observed for fetal death, but for women with a prior fetal death, we found a hazard ratio (HR) of 2.87 (95% CI 1.37, 6.01) for stillbirth (fetal death ≥22 completed gestational weeks) among those who lifted >200 kg/day. For preterm birth, we found an exposure-response relation for primigravid women, reaching a HR of 1.43 (95% CI 1.13, 1.80) for total loads >200 kg per day. These findings correspond to an excess fraction of 11% for stillbirth and 10% for preterm birth.

Conclusion

We found an increased risk of stillbirth among women with a prior fetal death, who lifted >200 kg/day, and an exposure-response relationship between occupational lifting and preterm birth among primigravid women. The study adds to a large body of prospective studies on occupational lifting and adverse pregnancy outcomes by refined exposure assessment.

MNK kinases facilitate c-myc IRES activity in rapamycin-treated multiple myeloma cells

When mTOR inhibitor rapalogs prevent cap-dependent translation of cell-cycle proteins like c-myc, continuing tumor cell growth depends on cap-independent translation, which is mediated by internal ribosome entry sites (IRESes) located in the 5'-UTR (untranslated region) of transcripts. To investigate if rapalog-induced activation of MNK kinases had a role in such IRES activity, we studied multiple myeloma (MM) cells. Rapamycin (RAP)-activated MNK1 kinase activity in MM cell lines and primary specimens by a mitogen-activated protein kinase-dependent mechanism. Pharmacological inhibition of MNK activity or genetic silencing of MNK1 prevented a rapalog-induced upregulation of c-myc IRES activity. Although RAP, used alone, had little effect on myc protein expression, when combined with a MNK inhibitor, myc protein expression was abrogated. In contrast, there was no inhibition of myc RNA, consistent with an effect on myc translation. In a RAP-resistant MM cell lines as well as a resistant primary MM specimen, co-exposure to a MNK inhibitor or MNK1 knockdown significantly sensitized cells for RAP-induced cytoreduction. Studies in MNK-null murine embryonic fibroblasts additionally supported a role for MNK kinases in RAP-induced myc IRES stimulation. These results indicate that MNK kinase activity has a critical role in the fail-safe mechanism of IRES-dependent translation when mTOR is inhibited. As kinase activity also regulated sensitivity to RAP, the data also provide a rationale for therapeutically targeting MNK kinases for combined treatment with mTOR inhibitors.

Short term benefits of post-operative oral dietary supplements in surgical patients

The present study was undertaken to investigate the short term clinical efficacy of oral dietary supplements administered post-operatively to patients undergoing predetermined moderate to severe gastrointestinal surgery. Trial end points for comparison included effects of oral dietary supplements on nutritional intake, nutritional status and incidence of serious complications. 54 patients who were scheduled to undergo predetermined moderate to major gastrointestinal surgical procedures entered the study. They were randomly assigned to receive a normal ward diet post-operatively or the same diet supplemented ad libitum by an oral nutritional sip feed. The study period was defined as commencing from the day patients were adjudged to be capable of ingesting 'free fluids' to the day of hospital discharge. 40 patients (20 in each group) completed the study. The mean daily energy intake (KCal/day) assessed from 7 day food diaries was significantly higher in the treatment group (1833 +/- SEM 99) than in the control group (1108 +/- 56, p < 0.0001). This increase occurred not only as a consequence of energy intake from the oral dietary supplements (470 +/- 30) but also because more energy was consumed from the ward diet by the treatment than the control patients (1353 +/- 92 vs 1108 +/- 56, p < 0.02). The mean daily protein intake g/day in the treatment group (66.0 +/- 3.4) was also greater than in the control group (52.9 +/- 29 p < 0.0001). This difference was due solely to the intake in protein from the oral dietary supplements (15.7 +/- 1.0), protein intake from the ward diet being similar in the treatment (50.1 +/- 3.2) and control (52.9 +/- 29) groups. Patients in the treatment group maintained their pre-operative weight where as control patients had lostsignificant amount of their pre-operative weight by study day 3 (4.5 +/- 12 kg and by discharge (4.7 +/- 1.2 kg, p < 0.02). Pre-operative muscle function as evidenced by grip strength dynamometry decreased to a greater extent in the control than treatment group patients by study day 3 (14.6 +/- 2.2 KPa vs 2.8 +/- 2.4 < 0.03) and by discharge (10.4 +/- 3.1 KPa vs 0.10 +/- 1.9 p < 0.03). The incidence of serious infections (pneumonia, wound infection) was significantly higher in the control group (10) than in the treatment group (3, p < 0.02). It is concluded that the prescription of oral dietary supplements on an ad libitum basis to post-operative patients undergoing moderate to major gastrointestinal surgery results in clinically significant short term benefits.

The significance of health anxiety and somatization in care-seeking for back and upper extremity pain

BACKGROUND

Patients with musculoskeletal pain account for a large number of consultations in primary care. Improving our understanding of factors that make patients seek care could be of interest in decision making and prevention in the health care system.

OBJECTIVES

Our objectives were to examine if health anxiety, somatization and fear-avoidance beliefs were of importance for care-seeking with either back pain or upper extremity pain and to look at possible differences between the two groups.

METHODS

This is a prospective study with a baseline questionnaire and 18 months follow-up. Using the International Classification for Primary Care (ICPC), we identified care-seekers with either back pain or upper extremity pain among the potential patients of eight GPs. For analysis, we used Cox proportional hazards regression analysis. Analysis was stratified by gender.

RESULTS

We found that previous regional pain was a strong predictor of care-seeking. Somatization was associated with seeking care for back pain. Health anxiety was a predictor among women suffering from back pain. Only previous pain was a predictor of care-seeking for upper extremity pain.

CONCLUSION

The study implies that prevention of back pain and upper extremity pain requires different strategies and that gender and health anxieties should be taken into account.

Counselling low-back-pain patients in secondary healthcare: a randomised trial addressing experienced workplace barriers and physical activity

OBJECTIVE

To assess if counselling by an occupational physician (OP) addressing experienced workplace barriers and physical activity integrated as a part of low-back pain (LBP) outpatient treatment influences pain, function and sick leave.

METHODS

Randomised controlled trial in the secondary healthcare sector with 3 months' follow-up. The participants were LBP patients who, independently of sick-leave status, expressed concerns about the ability to maintain their current job. Patients referred for surgery were excluded. The intervention consisted of two counselling sessions conducted by an OP addressing both workplace barriers and leisure-time physical activity. A workplace visit was performed if required. Pain, function and duration of sick leave due to LBP were primary outcomes.

RESULTS

A reduction in bodily pain and improvement in physical function both measured by the 36-item short-form health survey questionnaire in favour of the intervention group was found. The change in pain score was found to be clinically relevant. The risk of sick leave for at least 8 weeks due to LBP was significantly reduced in the intervention group. Two secondary outcomes, Fear Avoidance Beliefs about physical activity and maximum oxygen uptake, supported compliance and adherence to the part of the intervention focusing on enhanced physical activity.

CONCLUSION

Two short counselling sessions by an OP combining advice on meeting workplace barriers and enhancing physical activity had a substantial effect on important prognostic factors for LBP patients with moderate to severe symptoms diagnosed in outpatient rheumatological clinics.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13071157.

A comparative study of marine salmonid alphavirus subtypes 1-6 using an experimental cohabitation challenge model

A comparative challenge study of six marine isolates representing subtypes 1-6 of salmonid alphavirus (salmon pancreas disease virus, Genus Alphavirus, Family Togaviridae) was conducted in Atlantic salmon in a fresh water cohabitation trial. Histopathological lesions typical of pancreas disease were observed with all subtypes, and virus was re-isolated from serum of cohabitant fish in each case. Using a virus neutralization (VN) test neutralizing salmonid alphavirus (SAV) subtype 1 strain F93-125, VN antibodies were detected in all challenge groups, consistent with serological cross-reactivity between these subtypes. Using real-time RT-PCR, SAV RNA was detected in heart tissue from 2 to 3 weeks post-challenge (wpc) in all cohabitant groups excluding controls. The results obtained suggested differences in the dynamics of infection between strains of SAV and potentially between subtypes. Results for SAV subtypes 1 and 3 suggested essentially synchronous infection of cohabitant fish. These two study groups also had the highest virus load in heart tissue as measured by quantitative RT-PCR and also had the most extensive histopathological changes. In contrast, results for SAV subtypes 2 and 6 strains were consistent with asynchronous infection in the cohabitant fish and were characterized by slow spread, low virus loads and mild histopathological changes. The SAV subtype 4 and 5 strains occupied an intermediate position in this regard. Despite the use of concentration procedures, it was not possible to detect SAV RNA in water samples from selected study tanks. However, testing of faeces from the SAV subtypes 1, 3 and 6 challenge groups found positive signals in each beginning at 1-3 wpc and remaining detectable for a further 2-3 weeks. Parallel testing of mucus samples found these became positive at 2-3 wpc and remained positive for a further 1-3 weeks. These results demonstrate for the first time that shedding and transmission of virus may occur by both these routes and suggest that dispersal in these matrices should be included in any disease transmission models.