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Research Article  |   January 2006
The Effect of Three Alternative Keyboard Designs on Forearm Pronation, Wrist Extension, and Ulnar Deviation: A Meta-Analysis
Author Affiliations
  • Nancy A. Baker, ScD, OTR/L, is Assistant Professor, Department of Occupational Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, 5023 Forbes Tower, Pittsburgh, Pennsylvania 15260; nab36@pitt.edu
  • Erin L. Cidboy, MS, OTR/L, is Research Associate, Department of Occupational Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
Article Information
Evidence-Based Practice / Hand and Upper Extremity / Handwriting and Keyboarding
Research Article   |   January 2006
The Effect of Three Alternative Keyboard Designs on Forearm Pronation, Wrist Extension, and Ulnar Deviation: A Meta-Analysis
American Journal of Occupational Therapy, January/February 2006, Vol. 60, 40-49. doi:10.5014/ajot.60.1.40
American Journal of Occupational Therapy, January/February 2006, Vol. 60, 40-49. doi:10.5014/ajot.60.1.40
Abstract

The growth of computer keyboard use in the workplace is believed to be one important determinant of the increased prevalence of work-related musculoskeletal disorders of the upper extremity (MSD-UE). One possible contributing factor to the development of MSD-UE is the flat standard keyboard, which places the forearm and wrist in biomechanically awkward postures. This meta-analysis examines the efficacy of three alternative keyboard designs, adjustable slope (AS), split fixed-angle (FA), and adjustable open-tented (AT), in reducing forearm pronation, wrist extension, and ulnar deviation. Analyses of pooled effect size from six studies indicated that the AT had a large effect on pronation (r = 0.85) and ulnar deviation whereas the FA had a large effect only on ulnar deviation (r = 0.79). The AS was found to have a large effect (r = 0.66) on wrist extension. The FA had a moderate effect on pronation (r = 0.33) and wrist extension (r = 0.30). None of these keyboards were found to have a significant effect on all three postures. This meta-analysis has implications for clinicians by providing objective information that may assist with the selection of an alternative keyboard that best reduces an identified problematic posture.