Aims:To determine quantitative exposure-response relations between work with highly elevated arms and supraspinatus tendinitis, shoulder pain with disability, and shoulder pain without disability.Methods:A cross sectional study was conducted in a historical cohort of 1886 males from three occupational groups. Exposure measurements were performed for four consecutive working days in a random sample of 72 currently employed subjects. Individual work histories were obtained by questionnaire and register data. Health status was ascertained by physical examination blinded towards exposure and symptoms. Data were analysed by generalised estimating equation and multiple logistic regression with adjustment for potential confounders.Results:For current upper arm elevation above 90°, a duration increment of 1% of the daily working hours was associated with odds ratios of 1.23 (95% CI 1.10 to 1.39) for supraspinatus tendinitis, 1.16 (95% CI 1.08 to 1.24) for shoulder pain with disability, and 1.08 (95% CI 1.04 to 1.13) for shoulder pain without disability. The outcomes were not related to duration of employment in one of the three trades.Conclusions:Quantitative exposure-response relations were established between current work with highly elevated arms and clinically verified shoulder disorders. Substantial long term cumulative effects were not shown. A potential for primary prevention was revealed.

Preclinical and clinical proof-of-concept studies have suggested the effectiveness of pharmacological modulation of inflammatory cytokines in ischemic stroke. Experimental evidence shows that targeting tumor necrosis factor (TNF) and interleukin (IL)-1 holds promise, and these cytokines are considered prime targets in the development of new stroke therapies. So far, however, information on the cellular expression of TNF and IL-1 in the human ischemic brain is sparse.We studied 14 cases of human post-mortem ischemic stroke, representing 21 specimens of infarcts aged 1 to > 8 days. We characterized glial and leukocyte reactions in the infarct/peri-infarct (I/PI) and normal-appearing tissue (NAT) and the cellular location of TNF, TNF receptor (TNFR)1 and TNFR2, IL-1α, IL-1β, and IL-1 receptor antagonist (IL-1Ra). The immunohistochemically stained tissue sections received a score reflecting the number of immunoreactive cells and the intensity of the immunoreactivity (IR) in individual cells where 0 = no immunoreactive cells, 1 = many intermediately to strongly immunoreactive cells, and 2 = numerous and intensively immunoreactive cells. Additionally, we measured blood TNF, TNFR, and IL-1 levels in surviving ischemic stroke patients within the first 8 h and again at 72 h after symptom onset and compared levels to healthy controls.We observed IL-1α and IL-1β IR in neurons, glia, and macrophages in all specimens. IL-1Ra IR was found in glia, in addition to macrophages. TNF IR was initially found in neurons located in I/PI and NAT but increased in glia in older infarcts. TNF IR increased in macrophages in all specimens. TNFR1 IR was found in neurons and glia and macrophages, while TNFR2 was expressed only by glia in I/PI and NAT, and by macrophages in I/PI. Our results suggest that TNF and IL-1 are expressed by subsets of cells and that TNFR2 is expressed in areas with increased astrocytic reactivity. In ischemic stroke patients, we demonstrate that plasma TNFR1 and TNFR2 levels increased in the acute phase after symptom onset compared to healthy controls, whereas TNF, IL-1α, IL-1β, and IL-1Ra did not change.Our findings of increased brain cytokines and plasma TNFR1 and TNFR2 support the hypothesis that targeting post-stroke inflammation could be a promising add-on therapy in ischemic stroke patients.

Objective: To determine whether work performed with the arms in a highly elevated position is associated with alterations in the rotator cuff tendons as assessed by magnetic resonance imaging (MRI).Methods: A cross‐sectional study was performed in a historical cohort of male machinists, car mechanics, and house painters. The participants were right‐handed, ages 40–50 years, and had been employed in their trades for not less than 10 years. Seventy‐one percent of invited subjects participated (136 of 192). Lifetime upper arm elevation was assessed by direct measurements combined with individual work histories obtained by questionnaire and from registry data. Supraspinatus tendinopathy was evidenced by MRI signal intensity changes and morphologic alterations. Infraspinatus and subscapularis tendinopathy were also assessed. Additional outcomes were acromioclavicular joint degeneration and humeral head cysts. The MRI findings were evaluated by radiologists who were blinded to exposure status and symptoms.Results: An exposure–response relationship was found between lifetime upper arm elevation and supraspinatus tendinopathy, with an age‐adjusted odds ratio of 1.27 (95% confidence interval 1.02–1.60) for a 5‐month increase in the total number of full‐time working months spent with the arm elevated >90°.Conclusion: Work with the arms in a highly elevated position is associated with MRI‐diagnosed alterations in the supraspinatus tendon. By demonstrating the first part of a possible biologic pathway, the study corroborates the work‐relatedness of rotator cuff disorders.

Rheumatoid arthritis of the shoulder is a progressive and destructive joint disease, and similar to arthritis in other joints, progression of the disease is unpredictable and may stop at any stage of involvement. Between 1983 and 1996, more than 500 shoulder prostheses were implanted in patients at the authors' institution. Total shoulder replacement yields satisfactory short and long term results even in patients with severely destructed joints. Pain relief is reliable and significant as reported in short and long term studies. In most patients the functional result is good or acceptable. Although range of motion is only slightly increased, a satisfactory overall range of motion is achieved by most patients because of the unaffected scapulothoracic motion. However, deteriorating results, emphasizing the complexity of shoulder arthroplasty, were seen with increasing observation time in patients with rheumatoid arthritis. Proximal migration of the humeral prosthesis attributable to rotator cuff failure, with secondary eccentric glenoid loading and progressive loosening, is latent in patients with chronic progressive rheumatoid disease and was by far the most common complication (42%) in the present series.

Three-dimensional finite element analysis is one of the best ways to assess stress and strain distributions in complex bone structures. However, accuracy in the results may be achieved only when accurate input information is given. A semi-automated method to generate a finite element (FE) model using data retrieved from computed tomography (CT) was developed. Due to its complex and irregular shape, the glenoid part of a left embalmed scapula bone was chosen as working material. CT data were retrieved using a standard clinical CT scanner (Siemens Somatom Plus 2, Siemens AG, Germany). This was done to produce a method that could later be utilized to generate a patient-specific FE model. Different methods of converting Hounsfield unit (HU) values to apparent densities and subsequently to Young's moduli were tested. All the models obtained were loaded using three-dimensional loading conditions taken from literature, corresponding to an arm abduction of 90°. Additional models with different amounts of elements were generated to verify convergence. Direct comparison between the models showed that the best method to convert HU values directly to apparent densities was to use different equations for cancellous and cortical bone. In this study, a reliable method of determining both geometrical data and bone properties from patient CT scans for the semi-automated generation of an FE model is presented.