Repetitive Hand Use Not the Culprit in Carpal Tunnel

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Added Pianka: "This is not something new [among the scientific establishment]. Twenty years or so ago, it became a kind of media frenzy, and people in the [medical establishment] did not counter those inaccurate statements. Now, we have to go back and do scientific studies and refute something that wasn't done scientifically in the first place. It ran away with itself."

Carpal tunnel syndrome occurs when the median nerve in the wrist is compressed for long periods of time. This compression can cause permanent nerve damage if left untreated. According to the U.S. National Institutes of Health, carpal tunnel syndrome is five times more common in women than in men and most often occurs in people between the ages of 30 and 60.

Patients with carpal tunnel syndrome experience numbness in the hands and eventually develop weakness and atrophy of some of the small hand muscles that control the thumb.

For the new study, researchers compared evidence for biological and occupational causes of carpal tunnel syndrome using the Bradford Hill criteria, an accepted quantitative measure.

The average scores for biological causes such as genetics, age and race were twice those of occupational factors such as repetitive hand use. Also, the average strength of a cause-and-effect association was three times as strong for biological factors as for occupational factors.

The findings fit with prior knowledge. "One would expect a higher percentage of people who use their hands continuously and laboriously to get carpal tunnel, and that's never been the case," Kulick said. "Construction workers don't get it any more frequently. The smaller community of court reporters who don't stop all day for hours and hours, they don't really develop it any more than anyone else."

According to the study authors, the findings may affect disability, workers' compensation and personal-injury claims.

But, the conclusions aren't likely to have any bearing on treatment, although they may change discussions regarding prevention.

"We do not totally understand why it occurs, so it's hard to prevent," Kulick said. "Treatment would be the same."

More information

For more on carpal tunnel, visit the American Academy of Orthopaedic Surgeons.