Hand usage and movement is routinely performed by all individuals daily irrespective of age. These movements can vary and can be repetitive in nature. Exposure of the hard and soft tissues of the hand to prolonged repetitive activities could contribute to the development work related upper limb disorders (WRULD).
Within the work setting, work related upper limb disorders (WRULDs) rank high in the United Kingdom (UK), second only to back complaints. This paper reports the amount of tendon travel and swelling that occurs in the hand during repetitive office activities that have been associated with WRULDs.
Nine healthy adults (five males; four females) participated in the study.
A 30-minute laboratory-based simulated office activity that consisted of data entry, mouse clicking and dragging, and mouse scrolling tasks was performed. Participants wore a custom-made cost effective flexible electrogoniometric glove (FEG) as two experimental conditions were tested; namely, FEG - only, and FEG using a Splint (FEG - Splint).
The FEG - only condition produced a higher overall tendon travel compared to the FEG - Splint condition. Both hands presented no statistically significant differences in hand temperature (p > 0.05) and hand volume increments (p > 0.05) with respect to the FEG - only and FEG - Splint office activity experiments. All participants that showed a decrease in hand volumetric measurement produced final temperature measurements lower than initial temperature measurements taken at the commencement of the experiment. Based on participants' perception, the mouse scrolling task was deemed as most strenuous.
The findings can help to advise patients on biomechanical 'risks' associated with repetitive activities.
[Show abstract][Hide abstract] ABSTRACT: Computer use is increasingly common among many working populations, and concern exists about possible adverse effects of computer use, such as carpal tunnel syndrome (CTS).
To estimate the prevalence and incidence of possible CTS and to evaluate the contribution of use of mouse devices and keyboards to the risk of possible CTS.
A 1-year follow-up study with questionnaires conducted in 2000 and 2001 at 3500 workplaces in Denmark, followed on each of the 2 occasions by a clinical interview on symptom distribution and frequency.
The questionnaire was sent to 9480 members of a trade union, with an initial response rate of 73% (n = 6943), and 82% (n = 5658) at follow-up.
At baseline, there were 3 outcome measures: tingling/numbness in the right hand once a week or more as reported in the questionnaire; tingling, numbness, and pain in the median nerve in the right hand confirmed by clinical interview; and tingling, numbness, and pain in the median nerve in the right hand at night confirmed by clinical interview. At 1 year of follow-up the main outcome of interest was onset of symptoms among participants who had no or minor symptoms at baseline.
The overall self-reported prevalence of tingling/numbness in the right hand at baseline was 10.9%. The interview confirmed that prevalence of tingling/numbness in the median nerve was 4.8%, of which about one third, corresponding to a prevalence of 1.4%, experienced symptoms at night. Onset of new symptoms in the 1-year follow-up was 5.5%. In the cross-sectional comparisons and in the follow-up analyses, there was an association between use of a mouse device for more than 20 h/wk and risk of possible CTS but no statistically significant association with keyboard use.
The occurrence of possible CTS in the right hand was low. The study emphasizes that computer use does not pose a severe occupational hazard for developing symptoms of CTS.
JAMA The Journal of the American Medical Association 07/2003; 289(22):2963-9. DOI:10.1001/jama.289.22.2963 · 35.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Several investigators have developed biomechanical models of finger flexor tendon displacements during pinching or gripping exertions of hands. Landsmeer has developed the most comprehensive set of models for this purpose. This paper describes experiments in which various sized cadaver hands were used to statistically evaluate the Landsmeer models. In so doing, the effects of hand and wrist anthropometry are included. The results indicate that the tendons displace in relation to joint positions as described by that Landsmeer model in which the tendon is depicted as sliding over the curved articular surface of the proximal bone of the joint. Joint thickness effects were found to modify the parameters in the model as intuitively expected. An empirical prediction model of the anthropometric effects was developed. Further, the tendon displacements for various wrist orientations were expressed empirically for the first time and were shown to be consistent with expected anatomical considerations.
Journal of Biomechanics 02/1978; 11(3):119-28. DOI:10.1016/0021-9290(78)90004-0 · 2.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the relationship between carpal tunnel syndrome (CTS) and keyboard use at work in a general population.
A health status questionnaire was mailed to 2,465 persons of working age (25-65 years) who were randomly selected from the general population of a representative region of Sweden. The questionnaire required the subjects to provide information about the presence and severity of pain, numbness and tingling in each body region, employment history, and work activities, including average time spent using a keyboard during a usual working day. Those reporting recurrent hand numbness or tingling in the median nerve distribution were asked to undergo a physical examination and nerve conduction testing. The prevalence of CTS, defined as symptoms plus abnormal results on nerve conduction tests, was compared between groups of subjects that differed in their intensity of keyboard use, adjusting for age, sex, body mass index, and smoking status.
Eighty-two percent responded to the questionnaire, and 80% of all symptomatic persons attended the examinations. Persons who had reported intensive keyboard use on the questionnaire were significantly less likely to be diagnosed as having CTS than were those who had reported little keyboard use, with a prevalence that increased from 2.6% in the highest keyboard use group (> or = 4 hours/day), to 2.9% in the moderate use group (1 to <4 hours/day), 4.9% in the low use group (<1 hour/day), and 5.2% in the no keyboard use at work group (P for trend = 0.032). Using > or = 1 hour/day to designate high keyboard use and <1 hour/day to designate low keyboard use, the prevalence ratio of CTS in the groups with high to low keyboard use was 0.55 (95% confidence interval 0.32, 0.96).
Intensive keyboard use appears to be associated with a lower risk of CTS.
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