De Quervain's tenosynovitis is a stenosing tenosynovitis of the first dorsal compartment of the wrist and leads to wrist pain and to impaired function of the wrist and hand. It can be treated by splinting, local corticosteroid injection and operation. In this study effectiveness of local corticosteroid injections for de Quervain's tenosynovitis provided by general practitioners was assessed.
Participants with de Quervain's tenosynovitis were recruited by general practitioners. Short-term outcomes (one week after injections) were assessed in a randomised, placebo-controlled trial. Long-term effectiveness was evaluated in an open prospective cohort-study of steroid responders during a follow-up period of 12 months. Participants were randomised to one or two local injections of 1 ml of triamcinolonacetonide (TCA) or 1 ml of NaCl 0.9% (placebo). Non-responders to NaCl were treated with additional TCA injections. Main outcomes were immediate treatment response, severity of pain, improvement as perceived by participant and functional disability using sub items hand and finger function of the Dutch Arthritis Impact Measurement Scale (Dutch AIMS-2-HFF).
11 general practitioners included 21 wrists in 21 patients. The TCA-group had better results for short-term outcomes treatment response (78% vs. 25%; p = 0.015), perceived improvement (78% vs. 33%; p = 0.047) and severity of pain (4.27 vs. 1.33; p = 0.031) but not for the Dutch-AIMS-HFF (2.71 vs. 1.92; p = 0.112). Absolute risk reduction for the main outcome short-term treatment response was 0.55 (95% CI: 0.34, 0.76) with a number needed to treat of 2 (95% CI: 1, 3). In the cohort of steroid responders (n = 12) the beneficial effects of steroid injections were sustained during the follow-up of 12 months regarding severity of pain (p = 0.67) and scores of Dutch AIMS-2-HFF (p = 0.36), but not for patient perceived improvement (p = 0.02). No adverse events were observed during the 12 months of follow-up.
One or two local injections of 1 ml triamcinolonacetonide 10 mg/ml provided by general practitioners leads to improvement in the short term in participants with de Quervain's tenosynovitis when compared to placebo. The short-term beneficial effects of steroid injections for symptoms were maintained during the follow-up after 12 months.
Current Controlled Trials ISRCTN53171398
The Guyon's canal syndrome is a well known clinical entity and may have significant impact on patient's quality of life. We report a case of 43-year-old male who presented with complaints of pain and numbness in right hand and difficulty in writing for past one month. On imaging diagnosis of Guyon's canal syndrome because of tortuous ulnar artery was made with additional findings of DeQuervain's stenosing tenosynovitis and dorsal intercalated segmental instability syndrome with ligamentous injury and subsequently these were confirmed on surgery.
Although it is a rare syndrome, early diagnosis and treatment prevents permanent neurological deficits and improve patient's quality of life.
To assess the contribution of work-organisational and personal factors to the prevalence of work-related musculoskeletal disorders (WMSDs) among garment workers in Los Angeles.
This is a cross-sectional study of self-reported musculoskeletal symptoms among 520 sewing machine operators from 13 garment industry sewing shops. Detailed information on work-organisational factors, personal factors, and musculoskeletal symptoms were obtained in face-to-face interviews. The outcome of interest, upper body WMSD, was defined as a worker experiencing moderate or severe musculoskeletal pain. Unconditional logistic regression models were adopted to assess the association between both work-organisational factors and personal factors and the prevalence of musculoskeletal pain.
The prevalence of moderate or severe musculoskeletal pain in the neck/shoulder region was 24% and for distal upper extremity it was 16%. Elevated prevalence of upper body pain was associated with age less than 30 years, female gender, Hispanic ethnicity, being single, having a diagnosis of a MSD or a systemic illness, working more than 10 years as a sewing machine operator, using a single sewing machine, work in large shops, higher work–rest ratios, high physical exertion, high physical isometric loads, high job demand, and low job satisfaction.
Work-organisational and personal factors were associated with increased prevalence of moderate or severe upper body musculoskeletal pain among garment workers. Owners of sewing companies may be able to reduce or prevent WMSDs among employees by adopting rotations between different types of workstations thus increasing task variety; by either shortening work periods or increasing rest periods to reduce the work–rest ratio; and by improving the work-organisation to control psychosocial stressors. The findings may guide prevention efforts in the garment sector and have important public health implications for this workforce of largely immigrant labourers.
work organisation; musculoskeletal disorder; ergonomic; psychosocial; sewing machine
This study was conducted to develop a model describing the interaction between lifestyle, job, and postural factors and parts of the upper extremities in shipyard workers.
A questionnaire survey was given to 2,140 workers at a shipyard in Ulsan City. The questionnaire consisted of questions regarding the subjects' general characteristics, lifestyle, tenure, physical burden, job control, posture and musculoskeletal symptoms. The overall relationship between variables was analyzed by a structural equation model (SEM).
The positive rate of upper extremity musculoskeletal symptoms increased in employees who worked longer hours, had severe physical burden, and did not have any control over their job. Work with a more frequent unstable posture and for longer hours was also associated with an increased positive rate of musculoskeletal symptoms. Multiple logistic regression analysis showed that unstable posture and physical burden were closely related to the positive rate of musculoskeletal symptoms after controlling for age, smoking, drinking, exercise, tenure, and job control. In SEM analysis, work-related musculoskeletal disease was influenced directly and indirectly by physical and job stress factors, lifestyle, age, and tenure (p < 0.05). The strongest correlations were found between physical factors and work-related musculoskeletal disease.
The model in this study provides a better approximation of the complexity of the actual relationship between risk factors and work-related musculoskeletal disorders. Among the variables evaluated in this study, physical factors (work posture) had the strongest association with musculoskeletal disorders.
Work-related musculoskeletal disorders; Risk factors; Shipyard; Structural equation model
In recent years, increased knowledge of the pathogenesis of upper quadrant pain syndromes has translated to better management strategies. Recent studies have demonstrated evidence of peripheral and central sensitization mechanisms in different local pain syndromes of the upper quadrant such as idiopathic neck pain, lateral epicondylalgia, whiplash-associated disorders, shoulder impingement, and carpal tunnel syndrome. Therefore, a treatment-based classification approach where subjects receive matched interventions has been developed and, it has been found that these patients experience better outcomes than those receiving non-matched interventions. There is evidence suggesting that the cervical and thoracic spine is involved in upper quadrant pain. Spinal manipulation has been found to be effective for patients with elbow pain, neck pain, or cervicobrachial pain. Additionally, it is known that spinal manipulative therapy exerts neurophysiological effects that can activate pain modulation mechanisms. This paper exposes some manual therapies for upper quadrant pain syndromes, based on a nociceptive pain rationale for modulating central nervous system including trigger point therapy, dry needling, mobilization or manipulation, and cognitive pain approaches.
Upper quadrant; Pain; Sensitization; Neck; Thoracic; Manual therapy
This case study was conducted to evaluate the conservative management of a patient presenting with right sided wrist and thumb pain diagnosed as De Quervain’s tenosynovitis/tendinopathy.
A 49-year-old female warehouse worker and recreational cyclist with right-sided De Quervain’s tenosynovitis/tendinopathy that began after a long-distance cycling trip.
Intervention and outcome
Treatment included ultrasound, soft tissue and myofascial release therapy, tool assisted fascial stripping or “guasha”, acupuncture, mobilizations and kinesiology taping. Home advice included icing, rest, wrist bracing, elevation and eccentric rehabilitation exercises. The positive outcome was a complete resolution of the patient’s complaint.
This case demonstrates how De Quervain’s disease is a challenging condition to treat with conservative methods and can be aggravated with new exacerbating factors as treatment continues. In this case, the addition of the active care (including eccentric exercises and self-care) helped to reinforce the passive care given in the office and accelerate the recovery.
De Quervain’s disease; tenosynovitis; tendinopathy; tendinosis; chiropractic; exercise; rehabilitation; maladie de De Quervain; ténosynovite; tendinopathie; tendinose; chiropratique; exercices; réadaptation
We investigated occupational disparities in the risk of upper limb musculoskeletal disorders in a random sample of 2 656 French workers (age 20–59) participating in a study on the prevalence of work-related upper limb disorders, launched by the National Institute of Health Surveillance. Prevalence ratios (PR) of physician-diagnosed musculoskeletal disorders of the shoulder, elbow, wrist and hand (any of six leading disorders, rotator cuff syndrome, carpal tunnel syndrome) in manual vs. non-manual workers were calculated using Cox regression models with a constant time of follow-up and robust variance. 11% of men and 15% of women were diagnosed with an upper limb disorder. The risk was especially high in manual workers (PRs: 1.44 to 2.10). Physical work factors accounted for over 50% of occupational disparities overall, 62 (men) to 67% (women) for rotator cuff syndrome, and 96% (women) for carpal tunnel syndrome. We calculated that under lower levels of physical work exposures, up to 31% of cases among manual workers could have prevented. In working men and women, upper limb musculoskeletal disorders are frequent. Physical work exposures, such as repetitive and forceful movements, are an important source of risk, particularly among manual workers.
Adult; Cross-Sectional Studies; Female; France; epidemiology; Humans; Male; Middle Aged; Musculoskeletal Diseases; epidemiology; etiology; Occupational Diseases; epidemiology; etiology; Prevalence; Regression Analysis; Risk Factors; Upper Extremity
Introduction Upper extremity musculoskeletal disorders influence workers’ quality of life. Workstyle may be one factor to deal with in workers with pain in the upper extremity. The objective of this study was to determine if workstyle is a mediating factor for upper extremity pain in a changing work environment of office workers over time. Methods Office workers with upper extremity pain filled out a Workstyle questionnaire (WSF) at baseline (n = 110). After 8 and 12 months follow-up assessment took place. Participants were divided into a good and an adverse workstyle group at baseline. The presence of upper extremity pain in both groups was calculated and relative risks were determined. Chi-square tests were used. Results Eight months after baseline, 80% of the adverse and 45% of the good workstyle group reported pain. The relative risk (RR) of having upper extremity pain for the adverse compared to the good workstyle group was 1.8 (95% CI 1.08–2.86) (P = 0.055). Twelve months after baseline, upper extremity pain was more often presented in the adverse workstyle compared to the good workstyle group (RR = 3.0, (95% CI 1.76–5.11), P = 0.003). Twelve months after baseline, 100% of the adverse workstyle group and 33% of the good workstyle group reported pain in the upper extremity. Conclusion Workstyle seems to be a mediating factor for upper extremity pain in office workers in a changing work environment. It is recommended to assess workstyle among office workers with upper extremity pain, and to include workstyle behaviour in treatments.
UEMSD; Upper extremity pain; Workstyle; Questionnaires—Psychometrics
To investigate the reasons for the excess risk of upper limb musculoskeletal disorders among manual workers compared with other workers in a random sample of 2656 French men and women (20–59 years old) participating in a study on the prevalence of work related upper limb disorders conducted by France's National Institute of Health Surveillance.
Prevalence ratios (PR) of physician‐diagnosed musculoskeletal disorders of the shoulder, elbow, wrist, and hand (any of six leading disorders, rotator cuff syndrome, carpal tunnel syndrome) in manual versus non‐manual workers were calculated using Cox regression models with a constant time of follow up and robust variance.
11.3% of men and 15.1% of women were diagnosed with an upper limb disorder. The risk was especially high in manual workers (PRs: 1.40 to 2.10). Physical work factors accounted for over 50% of occupational disparities overall, 62% (men) to 67% (women) for rotator cuff syndrome, and 96% (women) for carpal tunnel syndrome. The authors calculated that under lower levels of physical work exposures, up to 31% of cases among manual workers could have been prevented.
In working men and women, upper limb musculoskeletal disorders are frequent. Physical work exposures, such as repetitive and forceful movements, are an important source of risk and in particular account for a large proportion of excess morbidity among manual workers.
biomechanical exposures; manual worker; musculoskeletal diseases; occupational exposures; upper extremity
Work-related upper extremity musculoskeletal disorders, including carpal tunnel syndrome, are prevalent among dentists and dental hygienists. An important risk factor for developing these disorders is forceful pinching which occurs during periodontal work such as dental scaling. Ergonomically designed dental scaling instruments may help reduce the prevalence of carpal tunnel syndrome among dental practitioners. In this study, 8 custom-designed dental scaling instruments with different handle shapes were used by 24 dentists and dental hygienists to perform a simulated tooth scaling task. The muscle activity of two extensors and two flexors in the forearm was recorded with electromyography while thumb pinch force was measured by pressure sensors. The results demonstrated that the instrument handle with a tapered, round shape and a 10 mm diameter required the least muscle load and pinch force when performing simulated periodontal work. The results from this study can guide dentists and dental hygienists in selection of dental scaling instruments.
dentistry; hand tool; electromyography
This review examines the evidence for an association between computer work and neck and upper extremity disorders (except carpal tunnel syndrome).
A systematic critical review of studies of computer work and musculoskeletal disorders verified by a physical examination was performed.
A total of 22 studies (26 articles) fulfilled the inclusion criteria. Results show limited evidence for a causal relationship between computer work per se, computer mouse and keyboard time related to a diagnosis of wrist tendonitis, and for an association between computer mouse time and forearm disorders. Limited evidence was also found for a causal relationship between computer work per se and computer mouse time related to tension neck syndrome, but the evidence for keyboard time was insufficient. Insufficient evidence was found for an association between other musculoskeletal diagnoses of the neck and upper extremities, including shoulder tendonitis and epicondylitis, and any aspect of computer work.
There is limited epidemiological evidence for an association between aspects of computer work and some of the clinical diagnoses studied. None of the evidence was considered as moderate or strong and there is a need for more and better documentation.
A longitudinal cohort of automobile manufacturing workers (n = 1214) was examined for: 1) prevalence and persistence of specific upper extremity musculoskeletal disorders (UEMSDs) such as lateral epicondylitis and de Quervain's disease, and non-specific disorders (NSDs) defined in symptomatic individuals without any specific disorder, and 2) disorder prognoses based on symptom characteristics and other factors.
Eight specific disorders were identified through case definitions based on upper extremity physical examinations and symptom surveys administered on three occasions over six years.
At baseline, 41% of the cohort reported upper extremity symptoms; 18% (n = 214) of these had NSDs. In each survey, tendon-related conditions accounted for over half of the specific morbidity. Twenty-five percent had UEMSDs in multiple anatomical sites, and most with hand/wrist disorders had two or more hand/wrist UEMSDs. Persistence for all specific disorders decreased with length of follow-up. Specific UEMSDs were characterized by greater pain severity and functional impairment, and more lost work days than NSDs.
Upper extremity symptoms and diagnoses vary over time. NSDs may be the early stages of conditions that will eventually become more specific. NSDs and overlapping specific UEMSDs should be taken into account in UEMSD classification.
To chronicle the conservative treatment and management of a 32-year old female patient presenting with radial wrist pain of 4 months duration, diagnosed as De Quervain’s stenosing tenosynovitis.
The primary clinical feature is wrist pain at the radial styloid with resultant impairment of wrist, hand, and thumb function.
Intervention and outcome
The conservative treatment approach consisted of activity modification, Graston Technique®, and eccentric training. Outcome measures included verbal pain rating scale, QuickDASH Disability/Symptom Score, and a return to activities of daily living (ADLs). The patient attained symptom resolution and at 6 month follow-up reported no recurrence of wrist pain.
A combination of conservative rehabilitation strategies may be used by chiropractors to treat De Quervain’s stenosing tenosynovitis and allow for an individual to return to pain free ADLs in a timely manner.
radial wrist pain; stenosing tenosynovitis; De Quervain’s; Graston Technique®; eccentric training; douleurs au niveau du bord radial du poignet; ténosynovite sténosante; De Quervain; technique Graston®; entraînement excentrique
To summarize systematic reviews that 1) assessed the evidence for causal relationships between computer work and the occurrence of carpal tunnel syndrome (CTS) or upper extremity musculoskeletal disorders (UEMSDs), or 2) reported on intervention studies among computer users/or office workers.
PubMed, Embase, CINAHL and Web of Science were searched for reviews published between 1999 and 2010. Additional publications were provided by content area experts. The primary author extracted all data using a purpose-built form, while two of the authors evaluated the quality of the reviews using recommended standard criteria from AMSTAR; disagreements were resolved by discussion. The quality of evidence syntheses in the included reviews was assessed qualitatively for each outcome and for the interventions.
Altogether, 1,349 review titles were identified, 47 reviews were retrieved for full text relevance assessment, and 17 reviews were finally included as being relevant and of sufficient quality. The degrees of focus and rigorousness of these 17 reviews were highly variable. Three reviews on risk factors for carpal tunnel syndrome were rated moderate to high quality, 8 reviews on risk factors for UEMSDs ranged from low to moderate/high quality, and 6 reviews on intervention studies were of moderate to high quality. The quality of the evidence for computer use as a risk factor for CTS was insufficient, while the evidence for computer use and UEMSDs was moderate regarding pain complaints and limited for specific musculoskeletal disorders. From the reviews on intervention studies no strong evidence based recommendations could be given.
Computer use is associated with pain complaints, but it is still not very clear if this association is causal. The evidence for specific disorders or diseases is limited. No effective interventions have yet been documented.
Few prospective studies have evaluated outcomes of workers with self-reported symptoms of upper extremity musculoskeletal disorders (UEMSD). Our objective was to study the three-year outcomes of workers with self-reported symptoms, with or without a positive physical examination.
In 1993–1994, 598 subjects highly exposed to repetitive work filled out a Nordic-style questionnaire. They underwent a standardised physical examination at that time and again in 1996–1997 by the same occupational physician. The three-year outcomes (based on physical examination) of workers with a self-administered questionnaire positive at baseline for UEMSD, with or without a positive physical examination, were studied.
The three-year incidence rate was 44.1%, with one third of these incident cases who had self-reported symptoms in 1993–1994. Workers with a positive questionnaire had a significantly higher risk of UEMSD at physical examination three year later (80.1% UEMSD cases with positive questionnaires n=354, versus 44.2% cases without positive questionnaires n=69, p<0.0001). Moreover, workers with positive questionnaires but without UEMSD diagnosed in 1993–1994 (n=177) had also a significantly higher risk of UEMSD at physical examination three years later (60.5% cases with positive questionnaires n=26, versus 38.8% cases without positive questionnaires n=52, p=0.01). Results were similar when gender and age were taken into account.
Workers highly exposed to repetitive movements had a high risk of developing UEMSD and should be followed closely in surveillance programmes. Workers with self-reported symptoms without UEMSD diagnosed in physical examination represented only one third of new cases three years later. However, their risk to develop UEMSD was significantly increased, compared with those without symptoms.
With computers rapidly carving a niche in virtually every nook and crevice of today’s fast-paced society, musculoskeletal disorders are becoming more prevalent among computer users, which comprise a wide spectrum of the Malaysian population, including office workers. While extant literature depicts extensive research on musculoskeletal disorders in general, the five dimensions of psychosocial work factors (job demands, job contentment, job control, computer-related problems and social interaction) attributed to work-related musculoskeletal disorders have been neglected. This study examines the aforementioned elements in detail, pertaining to their relationship with musculoskeletal disorders, focusing in particular, on 120 office workers at Malaysian public sector organizations, whose jobs require intensive computer usage.
Research was conducted between March and July 2009 in public service organizations in Malaysia. This study was conducted via a survey utilizing self-complete questionnaires and diary. The relationship between psychosocial work factors and musculoskeletal discomfort was ascertained through regression analyses, which revealed that some factors were more important than others were.
The results indicate a significant relationship among psychosocial work factors and musculoskeletal discomfort among computer users. Several of these factors such as job control, computer-related problem and social interaction of psychosocial work factors are found to be more important than others in musculoskeletal discomfort.
With computer usage on the rise among users, the prevalence of musculoskeletal discomfort could lead to unnecessary disabilities, hence, the vital need for greater attention to be given on this aspect in the work place, to alleviate to some extent, potential problems in future.
Malaysia; Musculoskeletal discomfort; Psychosocial work factors; Office worker
Stenosing tenosynovitis of the first dorsal compartment of the wrist (de Quervain's disease) is a common cause of radial wrist and hand pain and disability. Nonoperative management of the disease has been thought to provide only temporary relief of pain and swelling, while surgical intervention has been viewed as a more definitive treatment. This retrospective study examines the results of 58 patients who presented with de Quervain's disease from January 1993 through December 1995 and were initially treated with a combination steroid/lidocaine injection. After 1 to 3 years of follow-up, 35 patients had complete relief of symptoms with a single injection, 14 had relief of symptoms with two injections, 2 are still under observation, and 7 patients had to undergo operative management. These results indicate that in most patients with de Quervain's disease, treatment with a steroid/lidocaine injection can provide complete relief of symptoms.
The purpose of this study was to describe the health status and work limitations in injured workers with musculoskeletal disorders at 1 month post-injury, stratified by return-to-work status, and to document their return-to-work trajectories 6 months post-injury.
A sample of 632 workers with a back or upper extremity musculoskeletal disorder, who filed a Workplace Safety and Insurance Board lost-time claim injury, participated in this prospective study. Participants were assessed at baseline (1 month post-injury) and at 6 months follow-up.
One month post-injury, poor physical health, high levels of depressive symptoms and high work limitations are prevalent in workers, including in those with a sustained first return to work. Workers with a sustained first return to work report a better health status and fewer work limitations than those who experienced a recurrence of work absence or who never returned to work. Six months post-injury, the rate of recurrence of work absence in the trajectories of injured workers who have made at least one return to work attempt is high (38%), including the rate for workers with an initial sustained first return to work (27%).
There are return-to-work status specific health outcomes in injured workers. A sustained first return to work is not equivalent to a complete recovery from musculoskeletal disorders.
Health outcomes; Musculoskeletal disorders; Return to work; Work limitations; Workers’ compensation
Almost half of women treated with aromatase inhibitors (AI) develop AI-associated musculoskeletal symptoms (AIMSS) such as arthralgias, but the etiology is unclear. The upper extremities are frequently affected, especially wrists, hands, and fingers. AI use may also increase the risk of developing carpal tunnel syndrome. Tendon sheath fluid and tenosynovial changes have been demonstrated by imaging symptomatic AI-treated patients. We hypothesized that these abnormalities correlate with AIMSS.
Thirty consecutive patients initiating adjuvant therapy with letrozole or exemestane on a prospective clinical trial enrolled in a pilot study evaluating tendon and joint abnormalities at baseline and after 3 months of AI therapy. Patients underwent high resolution ultrasonography of the wrists bilaterally and completed the Health Assessment Questionnaire (HAQ) and pain Visual Analog Scale (VAS). AIMSS were defined as increase in HAQ or VAS score during AI therapy that exceeded a predefined cutoff.
Twenty-five subjects completed both baseline and 3 month assessments. During the first 12 months of AI therapy, 15 subjects developed AIMSS, and 13 discontinued therapy because of musculoskeletal symptoms. There was a trend toward an association between presence of tendon sheath abnormalities on wrist ultrasound at baseline and development of AIMSS (p=0.06).
Clinically relevant musculoskeletal symptoms develop in AI-treated women, leading to treatment discontinuation in a substantial percentage. However, patient-reported symptoms were not associated with changes visible on wrist ultrasonography in this pilot study.
breast cancer; aromatase inhibitor; arthralgia; ultrasonography; musculoskeletal
One of the factors associated with the high prevalence of upper extremity musculoskeletal disorders, such as carpal tunnel syndrome, among dental practitioners is the repeated high pinch force applied during periodontal scaling. The goal of this study was to determine the relationship between the pinch force applied during periodontal scaling and the forces generated at the tip of the tool. A linear biomechanical model that incorporated tool reaction forces and a calculated safety margin was created to predict the pinch force applied by experienced and inexperienced dentists during periodontal scaling.
Six dentists and six dental students used an instrumented scaling tool while performing periodontal scaling on patients. Thumb pinch force was measured by a pressure sensor, while the forces developed at the instrument tip were measured by a six-axis load cell. A biomechanical model was used to calculate a safety factor and to predict the applied pinch force.
For experienced dentists, the model was moderately successful in predicting pinch force (R2 = 0.59). For inexperienced dentists, the model failed to predict peak pinch force (R2 = 0.01). The mean safety margin was higher for inexperienced (4.88±1.58) than experienced (3.35±0.55) dentists, suggesting that students apply excessive force during scaling.
Pinch force; Grip force; Tool; Design; Dental
Force may be a risk factor for musculoskeletal disorders of the upper extremity associated with typing and keying. However, the internal finger flexor tendon forces and their relationship to fingertip forces during rapid tapping on a keyswitch have not yet been measured in vivo. During the open carpal tunnel release surgery of five human subjects, a tendon-force transducer was inserted on the flexor digitorum super-ficialis of the long finger. During surgery, subjects tapped with the long finger on a computer keyswitch, instrumented with a keycap load cell. The average tendon maximum forces during a keystroke ranged from 8.3 to 16.6 N (mean = 12.9 N, SD = 3.3 N) for the subjects, four to seven times larger than the maximum forces observed at the fingertip. Tendon forces estimated from an isometric tendon-force model were only one to two times larger than tip force, significantly less than the observed tendon forces (p = 0.001). The force histories of the tendon during a keystroke were not proportional to fingertip force. First, the tendon-force histories did not contain the high-frequency fingertip force components observed as the tip impacts with the end of key travel. Instead, tendon tension during a keystroke continued to increase throughout the impact. Second, following the maximum keycap force, tendon tension during a keystroke decreased more slowly than fingertip force, remaining elevated approximately twice as long as the fingertip force. The prolonged elevation of tendon forces may be the result of residual eccentric muscle contraction or passive muscle forces, or both, which are additive to increasing extensor activity during the release phase of the keystroke.
Over years it has been increasingly concerned with how upper extremity musculoskeletal disorders (UEMSDs) are attributed to psychosocial job stressors. A review study was conducted to examine associations between UEMSDs and psychosocial work factors, and to recommend what to consider for the associations. For studies in which the job demand-control-support (DCS) model or its variables were specifically employed, published papers were selected and reviewed. A number of studies have reported relationships between UEMSDs symptoms and psychosocial exposure variables. For example, the findings are: higher numbness in the upper extremity was significantly attributed to by less decision latitude at work; work demands were significantly associated with neck and shoulder symptoms while control over time was associated with neck symptoms; and the combination of high psychosocial demands and low decision latitude was a significant predictor for shoulder and neck pain in a female working population. Sources of bias, such as interaction or study design, were discussed. UEMSDs were shown to be associated with psychosocial work factors in various studies where the job DCS model was addressed. Nonetheless, this review suggests that further studies should be conducted to much more clarify the association between UEMSDs and psychosocial factors.
Upper extremity musculoskeletal disorders; Psychosocial work factors; Job DCS model
Introduction Some musculoskeletal disorders of the upper extremity are not readily classified. The study objective was to determine if there were symptom patterns in self-identified repetitive strain injury (RSI) patients. Methods Members (n = 700) of the Dutch RSI Patients Association filled out a detailed symptom questionnaire. Factor analysis followed by cluster analysis grouped correlated symptoms. Results Eight clusters, based largely on symptom severity and quality were formulated. All but one cluster showed diffuse symptoms; the exception was characterized by bilateral symptoms of stiffness and aching pain in the shoulder/neck. Conclusions Case definitions which localize upper extremity musculoskeletal disorders to a specific anatomical area may be incomplete. Future clustering studies should rely on both signs and symptoms. Data could be collected from health care providers prospectively to determine the possible prognostic value of the identified clusters with respect to natural history, chronicity, and return to work.
Case definition; Classification; MSD; RSI; Non-specific; Factor analysis
Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors.
A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs. Due to the subjectivity of LBP, six measures of LBP are captured: 1) any LBP, 2) LBP ≥ 5/10 pain rating, 3) LBP with medication use, 4) LBP with healthcare provider visits, 5) LBP necessitating modified work duties and 6) LBP with lost work time. Workers have thus far been enrolled from 30 different employment settings in 4 diverse US states and performed widely varying work. At baseline, workers undergo laptop-administered questionnaires, structured interviews, and two standardized physical examinations to ascertain demographics, medical history, psychosocial factors, hobbies and physical activities, and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of low back pain. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. The lifetime cumulative incidence of low back pain will also include those with a past history of low back pain. Incident cases will exclude prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression.
Data analysis of a prospective cohort study of low back pain is underway and has successfully enrolled over 800 workers to date.
Epidemiology; Ergonomics; Cohort; Low back pain; NIOSH lifting equation
Twelve cases of stenosing tenovaginitis at the radial styloid process (de Quervain's disease), including two bilateral cases, are reviewed. These patients presented the typical symptoms of pain just proximal to the radial styloid process accompanied by limitation of abduction of the thumb. Many previous reports have emphasized the frequency of aberrant tendons in this region and have implied that such anomalies may play a part in the etiology of this disorder. In our cases aberrant tendons were not found. Pronounced thickening of the tendon sheaths was present at operation and accumulations of fluid resembling ganglion formation were frequently noticed. All forms of therapy except surgical excision of the involved tendon sheaths were largely ineffective. This surgical procedure was so simple and satisfactory that it is recommended as the treatment of choice. The diagnosis of de Quervain's disease is easily missed unless the examining physician constantly keeps it in mind.