Musculoskeletal disorders of the upper extremity and ergonomic interventions

In terms of the estimated magnitude of the musculoskeletal disorders (MSDs), the 1988 National Health Interview Survey found a prevalence of almost 15% for the U.S. population (Lawrence et al., 1998), which stayed relatively constant at 13.9% for the 1995 survey (Praemer et al., 1999). However, the Social Security Supplemental Security Income survey of 1998 did indicate a noticeable increase in prevalence with age, 16.9% for those 50-59 years of age and 23.9% for those 60-65 years of age. In terms of upper limb MSDs, the 1988 National Health Interview Survey found a prevalence of 9.4% in the hand or wrist, with 1.5% being speci cally carpal tunnel syndrome and 0.4% being tendinitis (Tanaka et al., 1995). Interestingly when based on reported symptoms, the prevalence for carpal tunnel syndrome can be as high as 14.4%, but when referred for a clinical diagnosis the prevalence drops to 2.7% (Atroshi et al., 1999). A historical trend in MSDs is provided by the Occupational Safety and Health Administration in the Form 300 data. The number of cases labeled “disorders associated with repeated trauma” was relatively steady from 1976 to 1982 at around 22,000, then increased sharply to 332,100 by 1994, at which point there was a gradual reduction to 246,700 by 1999. This recent decline was speculated to have occurred as a result of a better recognition of such MSDs and the implementation of industrial health and safety programs (Conway and Svenson, 1998).