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| 2. |
- Gerhardsson, Lars, 1952, et al.
(författare)
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Vibration related symptoms and signs in quarry and foundry workers
- 2021
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 94, s. 1041-1048
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The development of vascular and neurosensory findings were studied in two groups of long-term exposed quarry and foundry workers with different vibration exposures, working conditions and work tasks. Methods The study included 10 quarry workers (mean age 43 yrs., mean exposure time 16 yrs.) and 15 foundry workers (35 yrs.; 11 yrs.) at two plants in Sweden. All participants completed a basic questionnaire and passed a medical examination including a number of neurosensory tests, e.g. the determination of vibration (VPT) and temperature (TPT) perception thresholds as well as a musculoskeletal examination of the neck, shoulders, arms and hands. Results A high prevalence of neurosensory findings (40%) was found among the quarry workers. Both groups, however, showed a low prevalence of vibration white fingers (VWF). Foundry workers showed significantly better sensitivity than quarry workers for all monofilament tests (p <= 0.016), TPT warmth in dig 2 (p = 0.048) and 5 dexter (p = 0.008), and in dig 5 sinister (p = 0.005). They also showed a better VPT performance in dig 5 dexter (p = 0.031). Conclusions Despite high vibration exposure, the prevalence of VWF was low. The high prevalence of neurosensory findings among the quarry workers may depend on higher A(8) vibration exposure and higher exposure to high-frequency vibrations. An age-effect and exposure to cold could also be contributing factors. The nervous system seems to be more susceptible to high-frequency vibrations than the vascular system. For neurosensory injuries, the current ISO 5349-1 standard is not applicable.
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| 3. |
- Johnson, Peter W, et al.
(författare)
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Comparison of measurement accuracy between two wrist goniometer systems during pronation and supination.
- 2002
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Ingår i: Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. - 1050-6411. ; 12:5, s. 413-20
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Tidskriftsartikel (refereegranskat)abstract
- Pronation and supination have been shown to affect wrist goniometer measurement accuracy. The purpose of this study was to compare differences in measurement accuracy between a commonly used biaxial, single transducer wrist goniometer (System A) and a biaxial, two-transducer wrist goniometer (System B) over a wide range of pronation and supination (P/S) positions. Eight subjects moved their wrist between -40 and 40 degrees of flexion/extension (F/E) and -10 and 20 degrees of radial/ulnar (R/U) deviation in four different P/S positions: 90 degrees pronation; 45 degrees pronation; 0 degrees neutral and 45 degrees supination. System A was prone to more R/U crosstalk than System B and the amount of crosstalk was dependent on the P/S position. F/E crosstalk was present with both goniometer systems and was also shown to be dependent on P/S. When moving from pronation to supination, both systems experienced a similar extension offset error; however R/U offset errors were roughly equal in magnitude but opposite in direction. The calibration position will affect wrist angle measurements and the magnitude and direction of measurement errors. To minimize offset errors, the goniometer systems should be calibrated in the P/S posture most likely to be encountered during measurement. Differences in goniometer design and application accounted for the performance differences.
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| 4. |
- Jonsson, Eythor, 1982, et al.
(författare)
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Reverse total shoulder arthroplasty provides better shoulder function than hemiarthroplasty for displaced 3- and 4-part proximal humeral fractures in patients over 70 years of age: a multicenter randomized controlled trial.
- 2021
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Ingår i: Journal of shoulder and elbow surgery. - : Elsevier BV. - 1532-6500 .- 1058-2746. ; 30:5, s. 994-1006
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Tidskriftsartikel (refereegranskat)abstract
- The most appropriate treatment for displaced multifragment proximal humeral fractures in elderly patients is currently unclear. Reverse total shoulder arthroplasty (rTSA) is a promising treatment option that is being used increasingly. The purpose of this study was to compare the outcome of rTSA with hemiarthroplasty (HA) for the treatment of displaced 3- and 4-part fractures in elderly patients.This is a multicenter, randomized controlled trial. We included patients over 70 years of age with displaced 3- or 4-part proximal humeral fractures between September 2013 and May 2016. The minimum follow-up was 2 years with outcome measures including the Constant score (primary outcome), the Western Ontario Osteoarthritis of the Shoulder (WOOS) index, the EQ-5D, range of motion, as well as pain and shoulder satisfaction assessed on a visual analog scale (VAS).We randomized 99 patients to rTSA (48 patients) and HA (51 patients). Fifteen patients were lost to follow-up, leaving 41 rTSA and 43 HA patients for analysis. Their mean age was 79.5 years and there were 76 females (90%). The rTSA group had a mean Constant score of 58.7, compared with 47.7 in the HA group, a mean difference of 11.1 points (95% CI, 3.0-18.9, P =0.007). Compared with HA, rTSA patients had greater mean satisfaction with their shoulder (79 vs 63mm, P = 0.011); flexion (125° vs 90°; P < 0.001) and abduction (112° vs 83°, P < 0.001), but there was no difference for WOOS, pain or the EQ-5D. We identified three and four adverse events in the rTSA and HA groups, respectively. For patients 80 years or older (n = 38), there was no difference between treatment with rTSA and HA for pain (17 vs 9mm, P = 0.17) or shoulder satisfaction (77 vs 74mm, P = 0.73).We found that rTSA provides better shoulder function than HA as measured with the Constant score, further emphasized by rTSA patients being more satisfied with their shoulder function. The difference appears to be mainly due to a better range of motion (abduction and flexion) in the rTSA group. The results also indicate that patients over 80 years of age benefit less from an rTSA than patients between 70 and 79 years of age.Level I; Randomized Controlled Trial; Treatment Study.
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| 5. |
- Jonsson, Per, 1952, et al.
(författare)
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Accuracy and feasibility of using an electrogoniometer for measuring simple thumb movements
- 2007
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 50:5, s. 647-59
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the accuracy and feasibility of using an electrogoniometer (Model SG 110; Biometrics, Gwent, UK) for measuring simple thumb movements. Thumb disorders have been associated with the use of hand held devices such as mobile phones and these devices have become an integral part of modern life. In 15 young subjects, the measurements of eight flexion/extension (Flex/Ext) and adduction/abduction (Ad/Ab) thumb positions were compared between a thumb-mounted electrogoniometer and manual goniometer (which was taken as the benchmark). Group mean electrogoniometric measurement errors were below 4 degrees and 5 degrees for Ad/Ab and Flex/Ext measurements, respectively. During mobile phone use, the electrogoniometers measured differences in maximal joint angle postures, which appeared to be related to differences in mobile phone size. High movement velocities may increase the risk of musculoskeletal injury and the results indicated that Ad/Ab movements were twice the speed of Flex/Ext movements during mobile phone use. Electrogoniometers have utility for studying thumb movements during mobile phone use and may be used to evaluate other thumb-based input devices.
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| 6. |
- Jonsson, Per, 1952, et al.
(författare)
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Anti-vibration Gloves - in Theory and Practice
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Vibrations from hand-held machinery are a major problem in the Swedish labour force. In 2009, 14% of men and 3% of women of employed in Sweden reported exposure to hand-arm vibration at least a quarter of their working time according to the Swedish Work Environment Authority (Arbetsmiljöverket 2010). It is tempting to imagine a protective glove that could reduce or even eliminate this problem. This report from the Department of Occupational and Environmental Medicine in Lund and Gothenburg describes how anti-vibration gloves (AVGs) are experienced, and how they work and affect the exposure from hand-held machines. Generally, all protective equipment disrupts work to a greater or lesser degree. Working without a helmet, protective mask, hearing protection, and protective clothing is preferred in most situations. Furthermore, the availability of gloves which are supposedly AV may give rise to an ethical dilemma: the user may handle the machines more intensely and for a longer time in the belief that the hand is protected from vibration damage. But are those AV claims true and how do these gloves perform in practice? Is the experience regarding the gloves that they dampen the vibrations? To what extent do the gloves disturb the worker and interfere with the work? How much damping can be expected when using low-speed and high-speed grinders, respectively? These issues will be discussed in the following report. Nine subjects, whose work task was to deburr and grind aircraft engine components, were given the opportunity to test a specific AVG for 3 months. They all worked with a variety of rotating air-powered and vibrating machines. Only one model of AVG was tested. The glove was CE-marked and was claimed to comply with standard ISO 10819:1996. The test subjects tried the glove for 3 months. After this period, they answered a questionnaire containing 14 questions including questions on hand temperature, grip, dexterity and self-reported vibration damping. To assess the usefulness of the AVG, the vibration level and vibration frequency spectrum were measured on the machines used by the subjects. During the measurements, a skilled operator performed a typical deburring task. The vibrations from many of the machines in this study, which are used over long periods for deburring, will be damped to some extent. But it is not obvious that this damping neither can be experienced, nor give reduced daily vibration exposure in accordance with the regulations, or reduce the risk of vibration injury in the hands. So-called “AVGs” generally give insufficient reduction in vibration exposure. This is demonstrated already by the standard for CE certification of AVGs. For a glove to protect against normal, low-frequency vibrations, it would have to be too heavy and thick to be practical. Despite the limitations of the protection that the CE-marked protective gloves offer against vibrations, we still recommend the use of gloves because: 1. High-frequency vibrations, which are presumed to be harmful, will be damped. 2. The gloves will ensure that vibrations will not be amplified. 3. Gloves keep the hands warm, which is believed to reduce vibration-related disorders.
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| 7. |
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| 8. |
- Jonsson, Per, 1952, et al.
(författare)
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Comparison of whole-body vibration exposures in buses: effects and interactions of bus and seat design
- 2015
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 58:7, s. 1133-1142
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Tidskriftsartikel (refereegranskat)abstract
- © 2014 Taylor & Francis Bus and seat design may be important for the drivers' whole-body vibration (WBV). WBV exposures in buses during actual operation were assessed. WBV attenuation performance between an air-suspension seat and a static pedestal seat in low-floor buses was compared; there were no differences in WBV attenuation between the seats. Air-suspension seat performance in a high-floor and low-floor bus was compared. Relative to the pedestal seat with its relatively static, limited travel seat suspension, the air-suspension seat with its dynamic, longer travel suspension provided little additional benefit. Relative to the measurement collected at the bus floor, the air-suspension seat amplified the WBV exposures in the high-floor bus. All WBV exposures were below European Union (EU) daily exposure action values. The EU Vibration Directive only allows the predominant axis of vibration exposure to be evaluated but a tri-axial vector sum exposure may be more representative of the actual health risks.
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| 9. |
- Jonsson, Per, 1952, et al.
(författare)
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Thumb joint movement and muscular activity during mobile phone texting - A methodological study
- 2011
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Ingår i: JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY. - 1050-6411. ; 21:2, s. 363-370
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Purpose: The extended intensive use of mobile phones and other devices for Information and Communication Technology (ICT) could expose the thumbs and fingers to operational stresses beyond their intended function which may generate pain and musculoskeletal disorders in the thumbs and the associated joints. Purpose: Studies characterizing biomechanical exposures associated with mobile phone use are limited to date and the use of electrogoniometry and EMG was assessed for characterizing thumb-based activities. Scope: The purpose was to investigate whether there were associations between thumb-based exposures registered with relatively easy-to-use electrogoniometric methods and more complicated EMG methods. Scope: Our hypothesis was that some outcome measures from the simpler electrogoniometric methods are related/correlated to and may be used as surrogate measure for the more complicated EMG methods. Conclusions: Due to low associations and the complementary nature of exposures collected with electrogoniometry and EMG, the results indicated both measures are necessary for characterizing thumb exposure during mobile phone text messaging. Only in a few, selected abduction/adduction activities, could electrogoniometry be used in lieu of EMG for assessing thumb exposures. (C) 2010 Elsevier Ltd. All rights reserved.
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| 10. |
- Jonsson, Per, 1952
(författare)
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Wrist and thumb joint postures and motions: Measurements using electrogoniometry and EMG
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Correct measurements of the joints’ extreme postures, velocity and repetitiveness are important for studies of the origin of musculoskeletal disorders. Posture measurements of wrist and thumb joints may also provide insights into input device designs that may reduce effort and/or facilitate productivity. Electrogoniometry offers a relatively simple and objective way to measure joint postures and motions. The expectation is that electrogoniometric instruments will provide better measures of postures and movements than the more subjective methods such as self-reporting or observation. In the first part of this thesis, two wrist goniometer systems were evaluated. The systems differed in how the goniometers were engineered and positioned over wrist and forearm. One system was integrated into a fingerless glove and floated over the forearm whereas the other system was mounted directly over the wrist. ”True” wrist positions were established with the aid of a fixture that allowed the positioning of the wrist in known angles. The “Crosstalk” – when movement in one plane artificially causes movement to be measured in another movement plane, “offset” – where the measured movement axes differ or are offset from the actual movement axes, and “range of motion” – the difference between the actual and measured range of motion of the joint, were compared. The measurement errors were substantial with both systems for simple, standardized wrist postures. However, the system with the transducers built-in in the fingerless glove had considerably less crosstalk errors and proved to have less between-subject differences. The similarities and differences in the measurement errors could be attributed to differences in systems design and methods to improve the accuracy of wrist posture measurement were provided. In the second part of this thesis, the accuracy and feasibility of measuring thumb postures and movements with a simple thumb-mounted electrogoniometer were evaluated. The ”true” thumb positions were established and defined using a manual goniometer. The posture measurement error of the thumb-based electrogoniometer was small relative to the manual goniometer, and on average, less than 5 degrees. A follow-up study determined whether this simple thumb-mounted goniometer could provide meaningful information on thumb posture during mobile phone use. When measuring thumb posture during SMS messaging, thumb posture was shown to be affected by the size of the mobile phone and differences in movement speeds were seen between the two movement axes of the thumb. Thumb movements in abduction/adduction were almost twice as fast as those in flexion/extension. It was also established that the thumb worked near the extreme ranges of motion – which is known to contribute to musculoskeletal disorders. Finally, this thesis determined whether measurements with a simple, thumb mounted electrogoniometer could be used in place of more complicated measures of muscle activity (EMG) for assessing musculoskeletal load during mobile phone use. Sophisticated correlation analyses of these different methods showed that only during very limited conditions could thumb goniometry be used in lieu of EMG measurements to assess musculoskeletal loads. Measurements indicated that the thumb's muscle activity most often complemented rather than replaced the simple goniometric measures of the thumb.
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