Repetitive motion injury is a term that is thrown around a lot these days. Typing at the keyboard or using the mouse for hours and hours upon end just seems like it has to be horrible for your joints, right? Never in the time of man has anybody used a single set of joints as much as we do now, right? Well, not so fast…
Carpal tunnel is big money–medications, doctor’s views, braces, surgery, books, disability claims, missed work, etc. Forty percent of work place injuries are attributed to carpal tunnel syndrome. We should sue computer makers and mouse makers! Make these horrible input devices illegal! Right?
Well, maybe not. What’s the current medical research regarding carpal tunnel?
“…computer use does not pose a severe occupational hazard for developing symptoms of carpal tunnel syndrome.”
–JAMA. 2003; 289:2963-2969.
One study (J Occup Med 1991 May;33(5):627-31) compared median nerve sensory and motor tests in a working population with significant repetitive hand usage to a normal population. No significant differences were detected between the two groups. They concluded that their “data provide[d] very little evidence for the concept of cumulative trauma as a prominent cause of carpal tunnel syndrome in American industry.”
Other studies have shown that up to two-thirds of people claiming carpal tunnel syndrome were either obese or had an underlying medical disease that could be causing or contributing to their condition. When these medical conditions were removed, Nathan (Ocup Med 1992 Apr;34(4):379-83) concluded that “individual characteristics, not job-related factors, are the primary determinants of slowing of sensory conduction of the median nerve and carpal tunnel syndrome.”
So you are unlikely to get carpal tunnel unless you have some other medical condition than predisposes you to it.
“Individual characteristics, not job-related factors, are the primary determinants of slowing of sensory conduction of the median nerve and carpal tunnel syndrome.”
— Ocup Med 1992 Apr;34(4):379-83.
Classically the associated diseases are the following: rheumatoid arthritis, menopause, hypothyroidism, acromegaly, end-stage renal disease, pregnancy, and obesity. Even then the data is not clear that the repetitive use contributes any.
Of course, these were over 10 years ago. Has this data been reproduced recently? What about computer usage?
The Journal of the American Medical Association studied Computer Use and Carpal Tunnel Syndrome in 2003. They screened and surveyed heavy-use computer workers looking for a cause and effect relationship. They really did not find much and concluded “that computer use does not pose a severe occupational hazard for developing symptoms of carpal tunnel syndrome. Harvard has recently sent out a press release partially titled “Computer Use Deleted As Carpal Tunnel Syndrome Cause.”
If you are worried about repetitive use injury from your computer use, read through some information regarding these types of injuries.
The current research shows that computer use has very little role in causing carpal tunnel syndrome. Common medical diseases that are known to cause carpal tunnel are much more likely to blame than any repetitive use injury.