Prevalence and risk factors of tendinitis and related disorders of the distal upper extremity among U.S. workers: comparison to carpal tunnel syndrome

Sex differences in the impact of musculoskeletal disorders on health-related quality of life: a population-based study, Campinas, SP - ISACamp 2014/15

This article aims to estimate the prevalence of musculoskeletal disorders (MD) on the adult population of Campinas, São Paulo, Brazil, verifying associated demographic and socioeconomic factors, and to analyze their impact on Health-Related Quality of Life (HRQoL) according to sex. A population-based study was conducted with 2,166 individuals using data from the ISACamp 2014/15. The Medical Outcomes Study SF-36-Item Short Form Health Survey (SF-36) was used to measure HRQoL according to MD. Prevalence ratios (PR) were estimated by Poisson regression. Musculoskeletal disorders had a prevalence of 8.5% (6.7% tendonitis and 2.7% work-related musculoskeletal disorders - WMSD). Results showed a higher prevalence of musculoskeletal disorders in women, active or on leave due to illness, and in individuals with higher education levels. Moreover, reduced HRQoL scores were observed in 6 of the 8 domains, due to MD. The mental component and physical component showed greater impairment respectively among women and men after self-reported WMSD. These findings point to substantial damage from musculoskeletal disorders on the population's HRQoL. WMSD affect the HRQoL of men and women distinctly.

Musculoskeletal discomfort and wrist flexor tendonitis among street sweepers and associated risk factors

BACKGROUND

Street sweepers are reported to suffer from high rates of work-related musculoskeletal discomfort worldwide, especially in their wrists.

OBJECTIVE

The study aimed to 1) determine the prevalence of musculoskeletal disorders and 2) specifically determine the prevalence of wrist flexor tendonitis and its associated risk factors among street sweepers.

METHODS

Three hundred and eighty-five sweepers employed by the Faisalabad Waste Management Company (FWMC) participated in this cross-sectional study. A self-structured questionnaire was used to collect data: the first section provided demographic information, the second assessed musculoskeletal disorders, and the third section assessed the wrist flexor tendonitis among street sweepers.

RESULTS

The mean age of the sweepers was 38.34 years. Out of 385 street sweepers, the prevalence of musculoskeletal discomfort was reported in 265 (68.83%). The prevalence of musculoskeletal discomfort in sweepers reported during COVID-19 according to the past 12 months, the highest three prevalence rates were 46.5% in the wrists/hands, 37.9% in the shoulders and 35.1% in the lower back. The three highest prevalence rates of musculoskeletal discomfort in sweepers according to the last 7 days were 29.6% in the wrists/hands, 24.4% in the lower back and 24.2% in the shoulders. Out of total 385 participants, prevalence of wrist flexor tendonitis was reported in 103 (26.8%) sweepers. Significant association was found (p < 0.05) between wrist flexor tendonitis and gender (p < 0.003), age (p < 0.05), working experience (p < 0.003), street sweeping distance (p < 0.01), number of brooms used per month (p < 0.002) and getting tired at the end of work (p < 0.001).

CONCLUSION

The prevalence of musculoskeletal discomfort and wrist flexor tendonitis seen during COVID-19 is high among sweepers, with wrist/hand being the most commonly reported region for pain. This study emphasizes the importance of providing guidelines about effective precautionary healthcare measures for street sweepers.

Study on a Bayes evaluation of the working ability of petroleum workers in the Karamay region, Xinjiang, China

Objectives

Use Bayes statistical methods to analyze the factors related to the working ability of petroleum workers in China and establish a predictive model for prediction so as to provide a reference for improving the working ability of petroleum workers.

Materials and methods

The data come from the health questionnaire database of petroleum workers in the Karamay region, Xinjiang, China. The database contains the results of a health questionnaire survey conducted with 4,259 petroleum workers. We established an unsupervised Bayesian network, using Node-Force to analyze the dependencies between influencing factors, and established a supervised Bayesian network, using mutual information analysis methods (MI) to influence factors of oil workers’ work ability. We used the Bayesian target interpretation tree model to observe changes in the probability distribution of work ability classification under different conditions of important influencing factors. In addition, we established the Tree Augmented Naïve Bayes (TAN) prediction model to improve work ability, make predictions, and conduct an evaluation.

Results

(1) The unsupervised Bayesian network shows that there is a direct relationship between shoulder and neck musculoskeletal diseases, anxiety, working age, and work ability, (2) The supervised Bayesian network shows that anxiety, depression, shoulder and neck musculoskeletal diseases (Musculoskeletal Disorders, MSDs), low back musculoskeletal disorders (Musculoskeletal Disorders, MSDs), working years, age, occupational stress, and hypertension are relatively important factors that affect work ability. Other factors have a relative impact on work ability but are less important.

Conclusion

Anxiety, depression, shoulder and neck MSDs, waist and back MSDs, and length of service are important influencing factors of work ability. The Tree Augmented Naïve Bayes prediction model has general performance in predicting workers’ work ability, and the Bayesian model needs to be deepened in subsequent research and a more appropriate forecasting method should be chosen.

Prevalence of Ganglion Cyst Formation After Wrist Arthroscopy: A Retrospective Longitudinal Analysis of 2420 Patients

BACKGROUND

Dorsal wrist ganglion cysts arise from the leakage of synovial fluid through tears in the scapholunate ligament and/or dorsal wrist capsule. An analogous disruption of the dorsal capsule is created with routine portal placement during wrist arthroscopy. We hypothesized that wrist arthroscopy would predispose to wrist ganglions.

METHODS

Using the Truven MarketScan Outpatient Services Database from 2015 to 2016, patients who underwent wrist arthroscopy and developed an ipsilateral wrist ganglion were identified. Exclusion criteria included ganglion diagnosis preceding arthroscopy and bilateral pathology. Postoperative ganglion diagnosis was modeled with logistic regression. Predictor variables included age, gender, comorbidities, and arthroscopic procedure.

RESULTS

In all, 2420 patients underwent wrist arthroscopy. Thirty (1.24%) were diagnosed with an ipsilateral wrist ganglion at a mean time of 4.0 months (standard deviation: 2.4, range: 0.2-9.0). Significant predictors of ganglion diagnosis included female gender (odds ratio [OR]: 4.0, P < .01) and triangular fibrocartilage complex and/or joint debridement (OR: 0.13, P < .01). By comparison, among all 24,718,751 outpatients who had not undergone wrist arthroscopy, 39,832 patients had a diagnosis of a wrist ganglion cyst (0.16%).

CONCLUSIONS

Wrist arthroscopy is associated with a postoperative rate of ganglion cyst formation that is nearly 8 times the rate in the general population. Additional studies are needed to investigate techniques that minimize the risk of this complication.

Proportion of upper extremity musculoskeletal disorders attributable to personal and occupational factors: results from the French Pays de la Loire study

BACKGROUND

Upper extremity musculoskeletal disorders (UEMSD) are one of the most common and costly occupational health problems. We aimed to assess the population-attributable fraction (PAF) of personal and occupational risk factors associated with incident UEMSD in a working population.

METHODS

From 2002 to 2005, a random sample of 3710 workers from the Pays de la Loire region in France, aged 20-59 were included by occupational physicians (OPs). Between 2007 and 2010, 1611 workers were re-examined by their OPs. Subjects free from UEMSD at baseline were included in this study (1275 workers, mean age: 38.2 years). Cox regression models with equal follow-up time and robust variance estimates were used to estimate age-adjusted and multivariable-adjusted relative risks (RRs) and their 95% confidence intervals (CIs). Based on multivariable models, PAF associated with each factor included in the models was estimated.

RESULTS

During the follow-up period, 143 (11%) cases of UEMSD were diagnosed. PAFs for factors associated with the incident UEMSD risk were 30% (7 to 51) for high physical exertion (RPE Borg scale ≥12), 12% (- 0.2 to 24) for low social support, 7% (- 3 to 17) for working with arms above shoulder level (≥2 h/day), 20% (12 to 28) for age group ≥45, 13% (3 to 22) for the age group 35-44, and 12% (0.3 to 24) for female gender.

CONCLUSIONS

Our study suggests that an important fraction of UEMSD can be attributed to occupational exposures after the contributions of personal and other work-related factors are considered. In terms of public health, our findings are in agreement with the ergonomic literature postulating that a high proportion of UEMSD are preventable through modifying workplace risk factors. Such information is useful to help public health practitioners and policy makers implement programs of prevention of UEMSD in the working population.

A single-pulsed electromagnetic field enhances collagen synthesis in tendon cells

Tendinopathy is a progressive pathology of tendon that is characteristic of imbalance between matrix synthesis and degeneration and is often caused by failure to adapt to mechanical loading. Non-steroidal anti-inflammatory medications (NSAIDS) are used as a conventional treatment to alleviate pain and swelling in the short term, but the ideal treatment for tendinopathy remains unclear. Here, we show a single pulsed electromagnetic field (SPEMF, 0.2 Hz) that up-regulated tenogenic gene expression (Col1a1, Col3a1, Scx, Dcn) and down-regulated inflammatory gene expression (Mmp1) in vitro. After five days of SPEMF stimulation (3 min/day), the collagen type I and total collagen synthesis protein levels were significantly increased. Under pro-inflammatory cytokine (IL-1β) irritation, the decreased expression of Col1a1/Col3a1 was up-regulated by SPEMF treatment, and the increased expression of Mmp1 was also reversed. From the above, it can be inferred that SPEMF that enhances matrix synthesis and reduces matrix degeneration may counteract the imbalance in tendinopathy. SPEMF application may be developed as a potential future strategy for therapeutic intervention in tendon disorders.

Histological assessment of a septum in the first dorsal compartment: a fresh cadaver study

Resistance of de Quervain's disease to conservative treatment has been associated with an intertendinous septum in the first compartment; little is known about the histological features of such a septum. This study aimed to examine the intertendinous septum histologically and note its variations. After dissecting the first extensor compartment of 24 hands from 12 fresh frozen cadavers, the presence of any intertendinous septa was determined. The length of the extensor retinaculum and intertendinous septum was measured; histological findings of the first compartment with or without septa were studied and compared with those of the third/fourth compartment. Intertendinous septa were observed in 12 of 24 wrists. Histological assessment of the intertendinous septum revealed tissue similar in composition to the retinaculum observed between the third and fourth compartments.

Ultrasound-Guided Dry Needling of the Healthy Rat Supraspinatus Tendon Elicits Early Healing Without Causing Permanent Damage

Overuse-induced tendinopathy is highly prevalent in the general population. Percutaneous fenestration, or dry needling, techniques have been increasing in popularity, but despite their current use, there are no controlled laboratory studies to provide fundamental support for this practice. The objective of this study was to establish a model for percutaneous needling of the rat supraspinatus tendon using ultrasound guidance and to evaluate the biological response of needling healthy tendon. A total of 44 male Sprague-Dawley rats (477 ± 39 g) were used to evaluate the effect of dry needling on healthy supraspinatus tendon properties. Ten rats were reserved as un-needled control animals, and the remaining animals underwent either mild or moderate bilateral needling protocols and were sacrificed at 1 or 6 weeks post-needling (n = 8-10/group). Color Doppler ultrasound imaging was performed to analyze blood flow within the tendon. Histological and immunohistochemical analyses were used to determine cellular, inflammatory, and extracellular matrix properties of the tissue. Finally, quasi-static tensile mechanical analysis was performed to obtain viscoelastic, structural, and material properties to evaluate the tendon healing outcome. Data were tested for normality, and then two-way analysis of variance tests were performed followed by post hoc tests for multiple comparisons. Both the mild and moderate needling groups caused a transient healing response at early time points as shown by a statistically significant (p < 0.05) reduction in mechanical properties, and increase in blood flow, inflammation, and production of collagen III and glycosaminoglycans as compared to the control. Furthermore, mild needling properties returned to or exceeded pre-needling values at the 6-week time point. Clinical significance: Needling the rat supraspinatus tendon is a feasible technique that causes a transient healing response followed by a return to, or improvement of, normal tendon properties, indicating potential applicability in understanding the effects of current practices utilizing dry needling of tendons in humans. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2035-2042, 2019.

Work-related upper extremity musculoskeletal disorders in the United States: 2006, 2009, and 2014 National Health Interview Survey

BACKGROUND

The annual incidence rate of work-related upper extremity musculoskeletal disorders (WUEMSDs) is increasing in US workers according to the United States Bureau of Labor Statistics (BLS). However, the prevalence of WUEMSDs among US total workers has not been estimated.

OBJECTIVE

We aimed to estimate the prevalence of WUEMSDs among US total workers and among each of major occupations and industries.

METHODS

We analyzed data from the National Health Interview Survey Arthritis supplements (2006, 2009, and 2014) among 50,218 current workers (age ≥18 years) to estimate the 30-day prevalence of WUEMSDs and of WUEMSDs affecting work using the SAS-callable SUDAAN software.

RESULTS

About 11.2 million workers reported WUEMSDs based on three surveys (2006, 2009, and 2014). The 30-day prevalence of WUEMSDs was 8.23% the prevalence of WUEMSDs affecting work was 1.24%. The Construction occupation and industry had the highest age- and sex-adjusted 30-day prevalence of WUEMSDs (10.98% for Construction occupation; 9.94% for Construction industry) and WUEMSDs affecting work (3.32% for Construction occupation; 2.31% Construction industry).

CONCLUSIONS

Our results show that construction workers had the highest prevalence of both WUEMSDs and WUEMSDs affecting work. They may be a priority group for interventions to reduce upper extremity musculoskeletal disorders.

An Upper Extremity Risk Assessment Tool Based on Material Fatigue Failure Theory: The Distal Upper Extremity Tool (DUET)

OBJECTIVE

Musculoskeletal tissues repeatedly loaded in vitro fail in accordance with material fatigue failure theory, and there is evidence to suggest that the same process occurs in vivo. The current paper presents a new upper extremity risk assessment tool, the Distal Upper Extremity Tool (DUET), predicated on material fatigue failure theory.

METHODS

DUET requires an estimate of force exertion level and the number of repetitions performed to derive estimates of damage and probabilities of experiencing a distal upper extremity outcome. Damage accrued over multiple tasks may be summed to estimate the cumulative damage (CD) accrued over a workday. Validation of this tool was performed using five distal upper extremity (DUE) outcomes (involving medical visits and pain) from an existing epidemiological database involving data from six automotive manufacturing plants. Logistic regression was used to assess the association of the log of the DUET CD measure to DUE outcomes.

RESULTS

Results demonstrated that the log of the DUET CD measure was highly associated with all five DUE outcomes in both crude analyses and those adjusted for site, age, gender, and body mass index ( p < .01). A model relating the continuous DUET log CD score to the probability of the DUE outcome Injury + Pain Last Year was developed, which demonstrated a significant dose-response relationship.

CONCLUSIONS

Results suggest that fatigue failure-based risk assessment techniques are highly associated with DUE outcomes and provide support for the notion that an underlying fatigue failure process may be involved in the development of upper extremity musculoskeletal disorders.

The Status of Musculoskeletal Disorders and Its Influence on the Working Ability of Oil Workers in Xinjiang, China

The purpose of this study was to investigate the status of musculoskeletal disorders (MSDs) and its influence on the working ability of oil workers, and to provide a theoretical basis for helping lessen the burden of MSDs and improve the man-machine environment of oil workers. The cluster sampling method was used to study 2000 workers who had been employed for more than 1 year in this field. We investigated the prevalence rate and the work ability index (WAI). A total of 1935 valid questionnaires were collected, a response rate of 96.75%. There were 1639 people who had suffered from MSDs in the past year, a prevalence rate of 84.7%. The damage detection rate in female oil workers was higher than in males, and the damage detection rate in workers aged 30 to 45 years was higher than that in the other two age groups. The detection rate in less highly-educated oil workers was higher than that in more highly-educated workers. The detection rate in divorced workers was higher than that in other groups. The detection rate in workers between the number of working years of 18 to 25 years was higher than in the other two groups. The detection rate in workers with a high professional title was significantly higher than that in lower-titled workers (p < 0.05). The results showed that the WAI scores of the subjects with MSDs were significantly lower than for subjects without MSDs (p < 0.05). In a logistic regression analysis, sex, number of working years and WAI index all had an impact on MSDs. We concluded that due to the demands of their role, the oil workers had serious MSDs that influenced their working ability.

Carbon-14 bomb pulse dating shows that tendinopathy is preceded by years of abnormally high collagen turnover

Tendons are essential weight-bearing structures that are often affected by tendinopathy, which leads to pain and impaired mobility. In healthy Achilles tendons, no significant renewal of the weight-bearing collagen matrix seems to occur during adult life, but tendinopathy may lead to increased turnover. The carbon-14 ([¹⁴C]) bomb pulse method was used to measure lifelong replacement rates of collagen in tendinopathic and healthy Achilles tendons (tendinopathic: n = 25, born 1937-1972. Healthy: n = 10, born 1929-1966). As expected, the healthy tendon collagen had not been replaced during adulthood, but in tendinopathic tendon, a substantial renewal had occurred. Modeling of the [¹⁴C] data suggested that one half of the collagen in tendinopathic matrix had undergone continuous slow turnover for years before the presentation of symptoms. This finding allows for a new concept in tendon pathogenesis because it suggests that either the symptoms of tendinopathy represent a late phase of a very prolonged disease process, or an abnormally high collagen exchange could be a risk factor for tendon disorders rather than being a result of disease.-Heinemeier, K. M., Schjerling, P., Øhlenschlæger, T. F., Eismark, C., Olsen, J., Kjær, M. Carbon-14 bomb pulse dating shows that tendinopathy is preceded by years of abnormally high collagen turnover.

Incidence and Risk Factors for Volar Wrist Ganglia in the U.S. Military and Civilian Populations

PURPOSE

To identify the incidence and demographic factors associated with volar wrist ganglia in both military and civilian beneficiary populations.

METHODS

The U.S. Department of Defense Management Analysis and Reporting Tool (M2) accesses a comprehensive database of all health care visits by military personnel and their dependents. Because there is no specific code for ganglions of the wrist, the database was searched for all military personnel and civilian beneficiaries with an International Classification of Diseases, 9th Revision, diagnosis of 727.41 (ganglion of a joint) or 727.43 (ganglion, unspecified location) between 2009 and 2014. Two random samples of 1000 patients were selected from both the military and the civilian beneficiary cohorts, and their electronic medical records were examined to identify those with volar wrist ganglia. The proportion of volar wrist ganglia was then applied to the overall population data to estimate the total incidence with a 95% confidence interval and 5% margin of error. Unadjusted incidence rates and adjusted incidence rate ratios were determined using Poisson regression, controlling for age, sex, branch of military service, and military seniority.

RESULTS

The unadjusted incidence of volar wrist ganglia is 3.72 per 10,000 person-years (0.04%/y) in female civilian beneficiaries, 1.04 per 10,000 person-years (0.01%/y) in male civilian beneficiaries, 7.98 per 10,000 person-years (0.08%/y) in female military personnel, and 3.73 per 10,000 person-years (0.04%/y) in male military personnel. When controlled for age, military personnel have a 2.5-times increased rate of volar wrist ganglia, and women have a 2.3-times increased rate. In the military cohort, female sex, branch of service, and seniority were significantly associated with the diagnosis of a volar wrist ganglion when controlled for age. In the civilian beneficiary cohort, only female sex was significant.

CONCLUSIONS

Military service members have higher rates of volar wrist ganglia diagnoses than their age- and sex-matched civilian counterparts. Women are significantly more likely to be diagnosed with a volar wrist ganglion, regardless of age or military status.

CLINICAL RELEVANCE

The epidemiology of volar wrist ganglia is poorly defined, and few studies have firmly defined demographic factors associated with the diagnosis. We provide the overall incidence rate of the diagnosis and report a significant association with female sex even when controlled for age.

Sex differences in the radial grooves in the first extensor compartment

OBJECTIVE

De Quervain tenosynovitis affects the first extensor compartment of the wrist and occurs more frequently in females. This high prevalence could not be explained by soft tissue. As the osseous anatomy has been mostly neglected, we aimed to compare the distal radius between the sexes.

MATERIALS AND METHODS

We evaluated the presence of a bony ridge on the floor of the first extensor compartment on CT images with multiplanar imaging.

RESULTS

We included 244 wrists (72 females, 172 males) in the study. A bony ridge was present in 58 (23.8 %) and absent in 186 (76.2 %) wrists. A ridge was present in 24 (33.3 %) wrists among females and 34 (19.8 %) wrists among males. A groove with a bony ridge was statistically associated with females.

CONCLUSION

We observed two tendon groove morphologies for the first extensor compartment. A groove with a bony ridge occurs more frequently in females. Further research is needed to clarify the relationship between the high frequency of a bony ridge and increased prevalence of de Quervain tenosynovitis in females.

Upper extremity musculoskeletal pain among office workers in three Spanish-speaking countries: findings from the CUPID study

OBJECTIVES

To estimate the prevalence and incidence of upper extremity musculoskeletal pain (UEMP) and related disability among office workers in Costa Rica, Nicaragua and Spain.

METHODS

Data from the multinational Cultural and Psychosocial Influences on Disability (CUPID) study on 947 (93%) participants at baseline with 90% follow-up after 12 months were employed. Logistic regression was used to estimate the associations (ORs and corresponding 95% CIs) between country and six outcomes: baseline prevalence of (1) UEMP in past 12 months, (2) UEMP in past month and (3) disabling UEMP in past month; (4) incidence of new UEMP at follow-up; (5) incidence of new disabling UEMP at follow-up and (6) persistence of UEMP at follow-up, after adjustment for sociodemographic, job-related and health-related covariates.

RESULTS

Baseline prevalence of UEMP in the past month was higher in Costa Rica (53.6%) (OR=1.89; 95% CI 1.36 to 2.62) and Nicaragua (51.9%) (OR=1.74; 95% CI 1.28 to 2.35) than in Spain (38.4%). Compared to Spain (33.2%), the incidence of new UEMP was 50.4% in Costa Rica (OR=2.04; 95% CI 1.34 to 3.12) and 60.2% in Nicaragua (OR=3.04; 95% CI 2.06 to 4.50). The incidence of disabling UEMP was higher in Nicaragua (OR=2.57; 95% CI 1.50 to 4.41) and Costa Rica (OR=2.16; 95% CI 1.22 to 3.84) when compared to Spain.

CONCLUSIONS

Prevalence of UEMP was approximately twofold higher and its incidence twofold to threefold higher in Costa Rica and Nicaragua as compared with Spain. Between-country differences were only partially explained by the covariates analysed. Research is needed to explore other aspects of work and cultural attributes that might explain the residual differences in UEMP.

Eccentric or Concentric Exercises for the Treatment of Tendinopathies?

Synopsis Tendinopathy is a very common disorder in both recreational and elite athletes. Many individuals have recurrent symptoms that lead to chronic conditions and termination of sports activity. Exercise has become a popular and somewhat efficacious treatment regime, and isolated eccentric exercise has been particularly promoted. In this clinical commentary, we review the relevant evidence for different exercise regimes in tendinopathy rehabilitation, with particular focus on the applied loads that are experienced by the tendon and how the exercise regime may affect these applied loads. There is no convincing clinical evidence to demonstrate that isolated eccentric loading exercise improves clinical outcomes more than other loading therapies. However, the great variation and sometimes insufficient reporting of the details of treatment protocols may hamper the interpretation of what may be the optimal exercise regime with respect to parameters such as load magnitude, speed of movement, and recovery period between exercise sessions. Future studies should control for these loading parameters, evaluate various exercise dosages, and think beyond isolated eccentric exercises to arrive at firm recommendations regarding rehabilitation of individuals with tendinopathies. J Orthop Sports Phys Ther 2015;45(11):853-863. Epub 14 Oct 2015. doi:10.2519/jospt.2015.5910.

The anatomy of the fibrous and osseous components of the first extensor compartment of the wrist: a cadaveric study

PURPOSE

De Quervain disease is the stenosing tenosynovitis of the first extensor compartment of the wrist. It is diagnosed with a history of pain at the radial aspect of the wrist and a positive Finkelstein test. Although anatomic variations, such as a septum within the compartment, are considered as risk factors, bony anatomy of distal radius and its correlation with the septa are studied scarcely in the literature.

METHODS

We dissected 50 wrists of 26 cadavers. Presence and location of a septum within the compartment was evaluated. We also observed the grooves at distal radius and their relation to the first extensor compartment and its content.

RESULTS

The septum was absent in 23 wrists (46%). A septum was present in 27 (54%) wrists (15 incomplete 30%, 12 complete 24%). At the distal radius, we classified three radial groove types as Type 1 on 28 (56%), Type 2 on 14 (28%), and as Type 3 on 8 (16%) wrists. There was a statistically significant relation between complete type of septa and Type 1 grooves (p = 0.002).

CONCLUSION

We investigated the bony structures of the compartment along with its content and we believe our results might guide clinicians who diagnose and treat de Quervain tenosynovitis.

Prevalence and work-relatedness of carpal tunnel syndrome in the working population, United States, 2010 National Health Interview Survey

BACKGROUND

Patterns of prevalence and work-relatedness of carpal tunnel syndrome (CTS) among workers offer clues about risk factors and targets for prevention.

METHODS

Data from an occupational health supplement to the 2010 National Health Interview Survey were used to estimate the prevalence of self-reported clinician-diagnosed CTS overall and by demographic characteristics. The proportion of these cases self-reported to have been attributed to work by clinicians was also examined overall and by demographic characteristics. In addition, the distribution of industry and occupation (I&O) categories to which work-related cases of CTS were attributed was compared to the distribution of I&O categories of employment among current/recent workers.

RESULTS

Data were available for 27,157 adults, including 17,524 current/recent workers. The overall lifetime prevalence of clinician-diagnosed CTS among current/recent workers was 6.7%. The 12-month prevalence was 3.1%, representing approximately 4.8 million workers with current CTS; 67.1% of these cases were attributed to work by clinicians, with overrepresentation of certain I&O categories.

CONCLUSIONS

CTS affected almost 5 million U.S. workers in 2010, with prevalence varying by demographic characteristics and I&O.

Upper limb cumulative trauma disorders for the orthopaedic surgeon

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

Ultrasound-assisted musculoskeletal procedures: A practical overview of current literature

Traditionally performed by a small group of highly trained specialists, bedside sonographic procedures involving the musculoskeletal system are often delayed despite the critical need for timely diagnosis and treatment. Due to this limitation, a need evolved for more portability and accessibility to allow performance of emergent musculoskeletal procedures by adequately trained non-radiology personnel. The emergence of ultrasound-assisted bedside techniques and increased availability of portable sonography provided such an opportunity in select clinical scenarios. This review summarizes the current literature describing common ultrasound-based musculoskeletal procedures. In-depth discussion of each ultrasound procedure including pertinent technical details, indications and contraindications is provided. Despite the limited amount of prospective, randomized data in this area, a substantial body of observational and retrospective evidence suggests potential benefits from the use of musculoskeletal bedside sonography.

Uphill running improves rat Achilles tendon tissue mechanical properties and alters gene expression without inducing pathological changes

Overuse Achilles tendinopathy is a common and challenging problem in sports medicine. Little is known about the etiology of this disorder, and the development of a good animal model for overuse tendinopathy is essential for advancing insight into the disease mechanisms. Our aim was to test a previously proposed rat model for Achilles tendon overuse. Ten adult male Sprague-Dawley rats ran on a treadmill with 10° incline, 1 h/day, 5 days/wk (17-20 m/min) for 12 wk and were compared with 12 control rats. Histological, mechanical, and gene-expression changes were measured on the Achilles tendons after the intervention, and local tendon glucose-uptake was measured before and after the intervention with positron emission tomography. No differences were detected between runners and controls in tissue histology or in glucose uptake, indicating that tendon pathology was not induced. Greater tendon tissue modulus (P < 0.005) and failure stress/body weight (P < 0.02) in runners compared with controls further supported that tendons successfully adapted to uphill running. Several genes of interest were regulated after 12 wk of running. Expression of collagen III and insulin-like growth factor I was increased, while collagen I was unchanged, and decreases were seen in noncollagen matrix components (fibromodulin and biglycan), matrix degrading enzymes, transforming growth factor-β1, and connective tissue growth factor. In conclusion, the tested model could not be validated as a model for Achilles tendinopathy, as the rats were able to adapt to 12 wk of uphill running without any signs of tendinopathy. Improved mechanical properties were observed, as well as changes in gene-expression that were distinctly different from what is seen in tendinopathy and in response to short-term tendon loading.

The WISTAH hand study: a prospective cohort study of distal upper extremity musculoskeletal disorders

Background

Few prospective cohort studies of distal upper extremity musculoskeletal disorders have been performed. Past studies have provided somewhat conflicting evidence for occupational risk factors and have largely reported data without adjustments for many personal and psychosocial factors.

Methods/design

A multi-center prospective cohort study was incepted to quantify risk factors for distal upper extremity musculoskeletal disorders and potentially develop improved methods for analyzing jobs. Disorders to analyze included carpal tunnel syndrome, lateral epicondylalgia, medial epicondylalgia, trigger digit, deQuervain’s stenosing tenosynovitis and other tendinoses. Workers have thus far been enrolled from 17 different employment settings in 3 diverse US states and performed widely varying work. At baseline, workers undergo laptop administered questionnaires, structured interviews, two standardized physical examinations and nerve conduction studies to ascertain demographic, medical history, psychosocial factors and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of musculoskeletal disorders. Repeat nerve conduction studies are performed for those with symptoms of tingling and numbness in the prior six months. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. Case definitions have been established. Point prevalence of carpal tunnel syndrome is a combination of paraesthesias in at least two median nerve-served digits plus an abnormal nerve conduction study at baseline. The lifetime cumulative incidence of carpal tunnel syndrome will also include those with a past history of carpal tunnel syndrome. Incident cases will exclude those with either a past history or prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression.

Discussion

A prospective cohort study of distal upper extremity musculoskeletal disorders is underway and has successfully enrolled over 1,000 workers to date.

The Strain Index (SI) and Threshold Limit Value (TLV) for Hand Activity Level (HAL): risk of carpal tunnel syndrome (CTS) in a prospective cohort

A cohort of 536 workers was enrolled from 10 diverse manufacturing facilities and was followed monthly for six years. Job physical exposures were individually measured. Worker demographics, medical history, psychosocial factors, current musculoskeletal disorders (MSDs) and nerve conduction studies (NCS) were obtained. Point and lifetime prevalence of carpal tunnel syndrome (CTS) at baseline (symptoms + abnormal NCS) were 10.3% and 19.8%. During follow-up, there were 35 new CTS cases (left, right or both hands). Factors predicting development of CTS included: job physical exposure (American conference of governmental industrial hygienists Threshold Limit Value (ACGIH TLV) for Hand Activity Level (HAL) and the Strain Index (SI)), age, BMI, other MSDs, inflammatory arthritis, gardening outside of work and feelings of depression. In the adjusted models, the TLV for HAL and the SI were both significant per unit increase in exposure with hazard ratios (HR) increasing up to a maximum of 5.4 (p = 0.05) and 5.3 (p = 0.03), respectively; however, similar to other reports, both suggested lower risk at higher exposures. Data suggest that the TLV for HAL and the SI are useful metrics for estimating exposure to biomechanical stressors.

PRACTITIONER SUMMARY

This study was conducted to determine how well the TLV for HAL and the SI predict risk of CTS using a prospective cohort design with survival analysis. Both the TLV for HAL and the SI were found to predict risk of CTS when adjusted for relevant covariates.

A COMPARISON OF ENDOSCOPIC AND OPEN TRIGGER FINGER RELEASE

The main complaint of the patients after an open trigger finger release is a discomfort at the incision site. In this prospective study, we compared the two consecutive groups of patients with trigger fingers. One was treated by an open approach and the other by the endoscopic release of the A1 pulley. Pre- and post-operative evaluation at seven, 30 and 90 days showed a faster recovery from the discomfort with a faster return to daily and working activities, after the endoscopic procedure.

Infrared (810 nm) low-level laser therapy in rat achilles tendinitis: a consistent alternative to drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used and can reduce musculoskeletal pain in spite of the cost of adverse reactions like gastrointestinal ulcers or cardiovascular events. The current study investigates if a safer treatment such as low-level laser therapy (LLLT) could reduce tendinitis inflammation, and whether a possible pathway could be through inhibition of either of the two-cyclooxygenase (COX) isoforms in inflammation. Wistar rats (six animals per group) were injected with saline (control) or collagenase in their Achilles tendons. Then, we treated them with three different doses of IR LLLT (810 nm; 100 mW; 10 s, 30 s and 60 s; 3.57 W cm(-2); 1 J, 3 J, 6 J) at the sites of the injections, or intramuscular diclofenac, a nonselective COX inhibitor/NSAID. We found that LLLT dose of 3 J significantly reduced inflammation through less COX-2-derived gene expression and PGE(2) production, and less edema formation compared to nonirradiated controls. Diclofenac controls exhibited significantly lower PGE(2) cytokine levels at 6 h than collagenase control, but COX isoform 1-derived gene expression and cytokine PGE(2) levels were not affected by treatments. As LLLT seems to act on inflammation through a selective inhibition of the COX-2 isoform in collagenase-induced tendinitis, LLLT may have potential to become a new and safer nondrug alternative to coxibs.

Ultrasound-assisted musculoskeletal procedures: A practical overview of current literature

Traditionally performed by a small group of highly trained specialists, bedside sonographic procedures involving the musculoskeletal system are often delayed despite the critical need for timely diagnosis and treatment. Due to this limitation, a need evolved for more portability and accessibility to allow performance of emergent musculoskeletal procedures by adequately trained non-radiology personnel. The emergence of ultrasound-assisted bedside techniques and increased availability of portable sonography provided such an opportunity in select clinical scenarios. This review summarizes the current literature describing common ultrasound-based musculoskeletal procedures. In-depth discussion of each ultrasound procedure including pertinent technical details, indications and contraindications is provided. Despite the limited amount of prospective, randomized data in this area, a substantial body of observational and retrospective evidence suggests potential benefits from the use of musculoskeletal bedside sonography.

Work-relatedness of selected chronic medical conditions and workers' compensation utilization: National health interview survey occupational health supplement data

BACKGROUND

An occupational health supplement (OHS) to the 1988 National Health Interview Survey (NHIS) bypassed many limitations of traditional occupational health surveillance systems, but the data collected about chronic work-related conditions have not yet been reported.

METHODS

We calculated the prevalence and proportion of cases related to work for the aggregation of 13 chronic conditions included in the NHIS-OHS, and for 11 conditions individually. For each of nine conditions, and for the aggregation of all conditions, we also calculated the prevalence of workers' compensation claims filed.

RESULTS

The overall prevalence of work-related chronic conditions was 7.5% (SE = 0.16). The work-related conditions with the highest prevalence were repeated trouble with the back/neck/spine (4.91%; SE = 0.13) and trouble hearing (1.14%; SE = 0.06). Overall, workers' compensation claims were filed for 39.0% (SE = 1.00) of work-related cases.

CONCLUSIONS

The burden of work-related illnesses in the US is substantial, and the workers' compensation system is underutilized.

Interleukins 4 and 13 modulate gene expression and promote proliferation of primary human tenocytes

Background

Tendon disorders (tendinopathies) pose serious biomedical and socioeconomic problems. Despite diverse treatment approaches, the best treatment strategy remains unclear. Surgery remains the last resort because of the associated morbidity and inconsistent outcomes. We hypothesized that, similar to fibroblasts in various organs, tendon fibroblasts (tenocytes) might be responsive to stimulation with interleukins (ILs), particularly IL-4 and IL-13. These two cytokines share sequence homology, receptor chains and functional effects, including stimulation of fibrogenesis. It is unknown whether tenocytes are responsive to stimulation with IL-4 or IL-13. If true, local use of these cytokines might be used to facilitate tendon repair in patients with tendinopathies or used for tendon tissue-engineering approaches to facilitate tenocyte growth on scaffolds in culture.

Results

Tendon tissues that would normally be discarded were obtained during reconstructive surgery procedures performed for clinical indications. Primary tenocytes were derived from Achilles, posterior tibial, flexor digitorum longus and flexor hallucis longus tendon tissue samples. Reverse transcriptase quantitative PCR (RT-qPCR) experiments revealed that mRNAs for the receptor (R) chains IL-4Rα, IL-13Rα1 and IL-13Rα2, but not the common γ-chain were present in all tested tendon tissues and in cultured tenocytes. Levels of IL-13R chain mRNAs were significantly higher than those of IL-4R mRNA. The cultures responded, in a dose-dependent fashion, to stimulation with recombinant human IL-4 or IL-13, by increasing proliferation rates 1.5 to 2.0-fold. The mRNA levels of 84 genes related to cell cycle regulation were measured by RT-qPCR after 6 h and 24 h of activation. The expression levels of several genes, notably CDK6 and CDKN2B changed more than twofold. In contrast to their effects on proliferation, stimulation with IL-4 or IL-13 had little if any effect on the levels of collagen mRNA or protein in cultured primary tenocytes. The mRNA levels of 84 other genes related to extracellular matrix and cell adhesion were also measured by RT-qPCR; expression of only five genes was consistently changed.

Conclusions

Stimulation with IL-4 or IL-13 could be used to facilitate tendon repair in vivo or to aid in tendon tissue engineering, through stimulation of tenocyte proliferation.

Prevalence and risk factors associated with musculoskeletal discomfort in New Zealand veterinarians

A cross-sectional study using a modified Nordic musculoskeletal questionnaire asked 867 New Zealand veterinarians about the presence or absence of musculoskeletal discomfort (MSD). Participants were asked if MSD affected their normal activities and if it required any period(s) of absence from work. Additional questions enquired about work activities, psychosocial factors and workload. A binary logistic regression analysis was used to quantify the association between identified risk factors and the presence of MSD requiring absence from work in the previous 12 months, controlling for the presence of known confounders. The overall period prevalence of MSD was 96%, 67% had normal activities being affected and 18% of participants reported that they had been absent from work due to MSD. The lower back was the body site most commonly reported for MSD (73%). Factors increasing the odds of MSD requiring time off work for clinical veterinarians were 10 year increases in age (OR 1.26, 95% CI 1.05-1.52), work involving awkward grip and hand movements 100% of time (OR 12.91, 95% CI 3.46-4.21) and those who were dissatisfied with the level and difficulty of their work (OR 2.27, 95% CI 1.11-6.56). These findings have implications for health, lifestyle and retention rates for veterinarians.

The pathogenesis of tendinopathy: balancing the response to loading

Tendons are designed to withstand considerable loads. Mechanical loading of tendon tissue results in upregulation of collagen expression and increased synthesis of collagen protein, the extent of which is probably regulated by the strain experienced by the resident fibroblasts (tenocytes). This increase in collagen formation peaks around 24 h after exercise and remains elevated for about 3 days. The degradation of collagen proteins also rises after exercise, but seems to peak earlier than the synthesis. Despite the ability of tendons to adapt to loading, repetitive use often results in injuries, such as tendinopathy, which is characterized by pain during activity, localized tenderness upon palpation, swelling and impaired performance. Tendon histological changes include reduced numbers and rounding of fibroblasts, increased content of proteoglycans, glycosaminoglycans and water, hypervascularization and disorganized collagen fibrils. At the molecular level, the levels of messenger RNA for type I and III collagens, proteoglycans, angiogenic factors, stress and regenerative proteins and proteolytic enzymes are increased. Tendon microrupture and material fatigue have been suggested as possible injury mechanisms, thus implying that one or more 'weak links' are present in the structure. Understanding how tendon tissue adapts to mechanical loading will help to unravel the pathogenesis of tendinopathy.

Corticosteroid injection for de Quervain's tenosynovitis

BACKGROUND

De Quervain's tenosynovitis is a disorder characterised by pain on the radial (thumb) side of the wrist and functional disability of the hand. It can be treated by corticosteroid injection, splinting and surgery.

OBJECTIVES

To summarise evidence on the efficacy and safety of corticosteroid injections for de Quervain's tenosynovitis.

SEARCH STRATEGY

We searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 2), MEDLINE (1966 to April 2009), EMBASE (1956 to April 2009), CINAHL (1982 to April 2009), AMED (1985 to April 2009), DARE, Dissertation Abstracts and PEDro (physiotherapy evidence database).

SELECTION CRITERIA

Randomised and controlled clinical trials evaluating the efficacy and safety of corticosteroid injections for de Quervain's tenosynovitis.

DATA COLLECTION AND ANALYSIS

After screening abstracts of studies identified by the search we obtained full text articles of studies which fulfilled the selection criteria. We extracted data using a predefined electronic form. We assessed the methodological quality of included trials by using the checklist developed by Jadad and the Delphi list. We extracted data on the primary outcome measures: treatment success; severity of pain or tenderness at the radial styloid; functional impairment of the wrist or hand; and outcome of Finkelstein's test, and the secondary outcome measures: proportion of patients with side effects; type of side effects and patient satisfaction with injection treatment.

MAIN RESULTS

We found one controlled clinical trial of 18 participants (all pregnant or lactating women) that compared one steroid injection with methylprednisolone and bupivacaine to splinting with a thumb spica. All patients in the steroid injection group (9/9) achieved complete relief of pain whereas none of the patients in the thumb spica group (0/9) had complete relief of pain, one to six days after intervention (number needed to treat to benefit (NNTB) = 1, 95% confidence interval (CI) 0.8 to 1.2). No side effects or local complications of steroid injection were noted.

AUTHORS' CONCLUSIONS

The efficacy of corticosteroid injections for de Quervain's tenosynovitis has been studied in only one small controlled clinical trial, which found steroid injections to be superior to thumb spica splinting. However, the applicability of our findings to daily clinical practice is limited, as they are based on only one trial with a small number of included participants, the methodological quality was poor and only pregnant and lactating women participated in the study. No adverse effects were observed.

Epidemiology of musculoskeletal injuries among students entering a chiropractic college

OBJECTIVE

The purpose of this study was to report the prevalence, distribution, and severity of injuries to students before entering chiropractic college and to explore the possible demographic risk factors to these injuries.

METHODS

A cross-sectional survey was administered to first-year chiropractic students (n = 255) of one chiropractic college. Survey questions were adopted from the Standardized Nordic and Outcome Assessment Health Status Questionnaires. Data were collected on severity and period of last perception of low back, hand/wrist (HW), and neck/shoulder (NS) injuries of the students before attending chiropractic college.

RESULTS

The response rate was 98.8% (N = 252), among which 66.7% were males. Injury prevalence to low back, HW, and NS before attending chiropractic college was 50.4%, 40.1%, and 53.2%, respectively. Of the respondents, 48.8% were overweight/obese and they were more likely to report injuries to HW (odds ratio, 2.10; 95% confidence interval, 1.25-3.51) and NS (odds ratio, 1.70; 95% confidence interval, 1.04-2.73) compared with those with normal weight. Among those with injuries, the mean body mass index for the females was significantly greater than for the males.

CONCLUSION

This study identified a high prevalence of musculoskeletal injuries among students before attending this particular chiropractic college. Only a small percentage of those injuries were severe enough to impede normal daily work. From this study sample, it seems that males entering this chiropractic college tend to report more injuries than females. However, females with high BMI seemed to report more previous injuries.

Glutamate and capsaicin-induced pain, hyperalgesia and modulatory interactions in human tendon tissue

Experimental glutamate and capsaicin-induced pain has not been described in tendon tissue despite the implications of addressing these receptors in pain management strategies. This study investigated pain induction and modulatory interactions by injecting glutamate (0.5 ml, 1 M) and capsaicin (0.5 ml, 5 microg, 33 microM) to human tendon tissue. Following the initial glutamate or capsaicin injection, a second injection of either glutamate (following capsaicin), capsaicin (following glutamate) or hypertonic saline (after both glutamate and capsaicin) was given. Twelve male volunteers participated. Subjects had four sequences of injections to tibialis anterior tendon over two sessions 1 week apart. Pain intensity responses were scored on a visual analogue scale (VAS). Pressure pain thresholds (PPTs) were assessed before, during and after pain induction. Capsaicin caused significantly higher peak pain scores compared to glutamate (P < 0.003) whilst glutamate pain was of significantly longer duration (P < 0.0003). Capsaicin following glutamate resulted in significantly higher average VAS scores 180-450 s after injection compared to capsaicin as primary injection (P < 0.05). PPTs were significantly reduced during capsaicin pain (72 +/- 5 and 80 +/- 6% of pre-pain values at the injection site and 2 cm proximal, P < 0.002). Following capsaicin, hypertonic saline and glutamate showed significant reductions in PPT at the same sites and to a similar degree compared to baseline (P < 0.002). The results indicate in tendon tissue a facilitation of response to capsaicin injection following glutamate injection. PPTs were only reliably reduced by capsaicin injection. These results emphasize the possible importance of peripheral glutamate receptor antagonists in pain management in musculoskeletal conditions.

Incidence of de Quervain's tenosynovitis in a young, active population

PURPOSE

De Quervain's tenosynovitis is thought to occur most frequently in women, with presentation of pain and swelling in the first dorsal extensor sheath. The epidemiology of this extensor tendinitis is not well described. We evaluated the incidence and demographic risk factors for de Quervain's tenosynovitis using a large database of military personnel.

METHODS

The Defense Medical Epidemiology Database (DMED) collects International Classification of Diseases, 9th Revision, and Clinical Modification (ICD-9-CM) coding information for every patient encounter occurring for United States military personnel. We queried the DMED system by race, gender, military service, rank, and age for the years 1998-2006 using the ICD-9 code 727.04, limiting data to first presentations. Multivariate Poisson regression was used to estimate the rate of de Quervain's tenosynovitis per 1000 person-years, as well as incidence rate ratios and 95% confidence intervals.

RESULTS

There were 11,332 cases of de Quervain's tenosynovitis in the population at risk of 12,117,749 person-years. Women had a significantly higher rate of de Quervain's tenosynovitis at 2.8 cases per 1000 person-years, compared to men at 0.6 per 1000 person-years. Age greater than 40 was also a significant risk factor, with this age category showing a rate of 2.0 per 1000 person-years compared to 0.6 per 1000 in personnel under 20 years. There was also a racial difference, with blacks affected at 1.3 per 1000 person-years compared to whites at 0.8.

CONCLUSIONS

In analysis of a large population, we have described the epidemiology of stenosing tenosynovitis of the first extensor compartment. Risk factors for de Quervain's in our population include female gender, age greater than 40, and black race.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

The basic science of tendinopathy

Tendinopathy is a common clinical problem with athletes and in many occupational settings. Tendinopathy can occur in any tendon, often near its insertion or enthesis where there is an area of stress concentration, and is directly related to the volume of repetitive load to which the tendon is exposed. Recent studies indicate tendinopathy is more likely to occur in situations that increase the "dose" of load to the tendon enthesis - including increased activity, weight, advancing age, and genetic factors. The cells in tendinopathic tendon are rounder, more numerous, and show evidence of oxidative damage and more apoptosis. These cells also produce a matrix that is thicker and weaker with more water, more immature and cartilage-like matrix proteins, and less organization. There is now evidence of a population of regenerating stem cells within tendon. These studies suggest prevention of tendinopathy should be directed at reducing the volume of repetitive loads to below that which induces oxidative-induced apoptosis and cartilage-like genes. The management strategies might involve agents or cells that induce tendon stem cell proliferation, repair and restoration of matrix integrity.

The quality and strength of evidence for etiology: example of carpal tunnel syndrome

PURPOSE

The purpose of this investigation was to evaluate the quality and strength of scientific evidence supporting an etiologic relationship between a disease and a proposed risk factor using a scoring system based on the Bradford Hill criteria for causal association.

METHODS

A quantitative score based on the Bradford Hill criteria (qBHs) was used to evaluate 117 articles presenting original data regarding the etiology of carpal tunnel syndrome: 33 (28%) that evaluated biological (structural or genetic) risk factors, 51 (44%) that evaluated occupational (environment or activity-related) risk factors, and 33 (28%) that evaluated both types of risk factors.

RESULTS

The quantitative Bradford Hill scores of 2 independent observers showed very good agreement, supporting the reliability of the instrument. The average qBHs was 12.2 points (moderate association) among biological risk factors compared with 5.2 points (poor association) for occupational risk factors. The highest average qBHs was observed for genetic factors (14.2), race (11.7), and anthropometric measures of the wrist (11.3 points) with all studies finding a moderate causal association. The highest average qBHs among occupational risk factors was observed for activities requiring repetitive hand use (6.5 points among the 30 of 45 articles that reported a causal association), substantial exposure to vibration (6.3 points; 14 of 20 articles), and type of occupation (5.6 points; 38 of 53 articles), with the findings being much less consistent.

CONCLUSIONS

According to a quantitative analysis of published scientific evidence, the etiology of carpal tunnel syndrome is largely structural, genetic, and biological, with environmental and occupational factors such as repetitive hand use playing a minor and more debatable role. Speculative causal theories should be analyzed through a rigorous approach prior to wide adoption.

Common tendinopathies in the upper and lower extremities

Overuse tendon injuries (tendinopathies) present a challenge to sports medicine patients and clinicians. Despite the high prevalence of tendinopathy in recreational and competitive athletes, treatment is often hampered by contradictory definitions and descriptions of the underlying pathology, with a limited repertoire of evidence-based treatments. This review provides the clinician with a basic overview of tendon structure and pathophysiology, and highlights the most common tendinopathies affecting the upper and lower extremities, including an update on recent advances in conservative management.

Potential of ultrasonography for epidemiological study of work-related wrist tenosynovitis

OBJECTIVE

To explore the possible role of ultrasonography in case definitions for epidemiological studies of work-related wrist tenosynovitis.

METHODS

Clinical and ultrasonography (7.5 MHz linear probe) data systematically collected from meat workers (n = 128) with biomechanical exposure characterisation were analysed. The diagnostic accuracy of different combinations of potentially relevant ultrasonography findings (nonhomogeneity, thickening and anechoic halo) was evaluated using symptomatology as a reference standard. The concordance between ultrasonography findings and symptoms was then analysed.

RESULTS

Analysis of wrist biomechanical exposure was suggestive of increased prevalence of musculoskeletal disorders. Using symptoms as a reference standard, each of the three ultrasonography findings (and their combinations) showed good specificity (> or =85%) accompanied by low sensitivity (<60%); the positive likelihood ratio for at least two findings was 4.1. kappa Values (95% confidence intervals) between symptoms and different sets of ultrasonography findings were as follows: for non-homogeneity, kappa = 0.31 (0.19 to 0.43); at least one finding, kappa = 0.28 (0.16 to 0.40); at least two findings, kappa = 0.32 (0.20 to 0.44); all p<0.01.

CONCLUSION

The use of ultrasonography in symptomatic subjects could contribute to a more specific epidemiological case definition of wrist tenosynovitis. The results of this study could help orient future research in this direction.

Upper extremity mononeuropathy among engineers

OBJECTIVES

The objectives of this study were to estimate the prevalence of mononeuropathy at the wrist among engineers who use computers and to identify associated risk factors.

METHODS

This is a cross-sectional study of 202 engineers using questionnaires and electrophysiological nerve testing. The definition for median or ulnar mononeuropathy required the combination of distal upper extremity discomfort and abnormal distal motor latency.

RESULTS

The prevalence of neuropathy at the wrist among engineers was 10.3% (right median), 3.4% (left median), 1.8% (right ulnar), and 2.9% (left ulnar). Logistic regression analysis identified three variables with positive associations (body mass index, hours of computer use, and antihypertensive medication) and three variables with negative associations (typing speed, driving hours, total break time).

CONCLUSIONS

Mononeuropathies at the wrist occur among computer-using engineers and are related to a number of factors, including hours of computer use.

Epidemiologic surveillance of upper-extremity musculoskeletal disorders in the working population

OBJECTIVE

Since 2002, an epidemiologic surveillance system of work-related, upper-limb musculoskeletal disorders (MSDs) has been implemented in France's Pays de la Loire region to assess the prevalence of MSDs and their risk factors in the working population.

METHODS

The surveillance was based on a network of occupational physicians (OPs) and used the recommendations of a group of European experts (criteria document consensus). In 2002-2003, 80 of 400 OPs volunteered to participate. All underwent a training program to standardize the physical examination. Health status was assessed by self-administered questionnaire and physical examination. Occupational risk factors were assessed by self-administered questionnaire. Exposure scores were computed for each anatomic zone by summing the risk factors taken into account by the criteria document.

RESULTS

More than 50% of the 2,685 men and women randomly included in 2002-2003 experienced nonspecific musculoskeletal symptoms during the preceeding 12 months and approximately 30% experienced them in the preceeding week. The prevalence of clinically diagnosed MSDs was high: approximately 13% of workers experienced at least 1 of the MSDs. The most frequent disorder was rotator cuff syndrome followed by carpal tunnel syndrome and lateral epicondylitis. The prevalence of MSDs increased with age and varied widely across economic sectors and occupations. More than half of the workers were exposed to at least 2 risk factors of MSDs. Exposure varied according to industrial activity and occupation. According to the criteria document, a high percentage of MSD cases could be classified as probably work related (95% in men and 89% in women age <50, and 87% in men and 69% in women age >50).

CONCLUSION

Nonspecific upper-limb symptoms and specific upper-limb MSDs are common in the working population. These results show the need to implement prevention programs in most sectors to reduce the prevalence of MSDs.

Course of symptoms and median nerve conduction values in workers performing repetitive jobs at risk for carpal tunnel syndrome

BACKGROUND

Carpal tunnel syndrome (CTS) is a common occupational disorder associated with repetitive manual work. Little information exists about the possible relation between the variation of biomechanical hand/wrist exposure and the development of symptoms and median nerve conduction values.

AIMS

To investigate the prevalence of CTS in a group of workers exposed to intensive use of the hands and the course of symptoms and median nerve conduction values after a period of reduced exposure to biomechanical risk factors.

METHODS

CTS was assessed in assembly and non-assembly line workers by means of clinical examinations and nerve conduction studies (NCS). Ergonomic analysis was conducted for each assembly line workstation.

RESULTS

Prevalence of CTS was significantly higher in assembly line workers compared to non-assembly line workers but there was a high prevalence of median nerve conduction abnormalities in both groups (60/102 hands and 40/110 hands, respectively). In a sizable proportion of both groups there was no relationship between symptoms and electrodiagnostic findings (45 hands and 48 hands in assembly and non-assembly line workers, respectively). When assembly line workers were re-examined after 2 years following a period of reduced work schedule, a significant proportion reported resolution of symptoms or had reverted to having normal NCS.

CONCLUSIONS

In our study, repetitive work was associated with a higher level of CTS and abnormal NCS. These findings appeared to be reversible following a period of less repetitive work. Overall, there was generally poor correlation between symptoms and electrodiagnostic findings.

A modified thumb spica splint for thumb injuries in the ED

There are a significant number of hand and upper extremity injuries treated in US emergency departments (EDs) each year. Many of these involve the thumb and wrist. These injuries encompass the range from fractures, strains, and sprains to more specific injuries such as gamekeeper thumb and de Quervain tenosynovitis. These injuries often require diagnosis, splinting, and referral to a hand or orthopedic surgeon. The splint described in this article is presently being used for patients with de Quervain tenosynovitis, but it may have more widespread application in emergency medicine. It is a safe and simple splint that is underused in EDs for splinting thumb injuries.

Trends in work-related musculoskeletal disorder reports by year, type, and industrial sector: a capture-recapture analysis

BACKGROUND

Musculoskeletal disorders (MSD) are thought to be declining based on Bureau of Labor Statistics survey data, but there is also evidence of MSD under-reporting, raising the possibility of contrary trends. The magnitude of MSD under-reporting over time, and its industry distribution have not been adequately described.

METHODS

Capture-recapture analysis of 7 years of Connecticut MSD (1995-2001), utilizing Workers' Compensation and physician reporting data was performed.

RESULTS

Only 5.5%-7.9% of MSD cases appear to be reported to Workers Compensation annually. The capture-recapture estimated average annual rate for upper-extremity MSD was 133.1 per 10,000 employed persons, far above BLS rates. By industry, Manufacturing, State Government, and the Finance/Insurance/Real Estate sectors all had significantly higher MSD rates than Wholesale/Retail Trade.

CONCLUSIONS

Upper-extremity MSD appears to be significantly under-reported, and rates are not decreasing over time. Capture-recapture methods provide an improved surveillance method for monitoring temporal trends in injury rates.