Scope of the Problem

Each year, tens of thousands of U.S. workers sustain repetitive motion injuries. The Bureau of Labor Statistics recorded 73,195 repetitive motion injuries, including tendinosis and carpal tunnel syndrome, in private industry in 1999. This number translates to about 1 out of every 1250 full-time workers that year. Tendinosis and carpal tunnel syndrome accounted for 44,504 injuries in 1999. These numbers would be even higher if they included injuries to government workers and athletes. Also, these numbers only include the injuries that are reported to the BLS, and some under-reporting probably takes place.

Workplace Injuries

The Bureau of Labor Statistics (BLS) keeps track of the number of occupational illnesses and injuries that occur in private industry each year. They do not track these numbers for public industry jobs (government). They track many different kinds of injuries, including carpal tunnel syndrome and "tendinitis." They track various subcategories for each kind of injury, such as how many of the injuries are caused by repetitive motion. All of the carpal tunnel syndrome injuries are attributed to repetitive motion. Most of the tendinitis category is really tendinosis because most of the injuries are caused by repetitive motion and are not acute injuries. Most acute tendon injuries are included in the BLS category "Sprains, Strains, and Tears."

The BLS reports that 73,195 private industry workers sustained repetitive motion injuries in 1999 (including only injuries involving days away from work). Tendinosis and carpal tunnel syndrome accounted for 44,504 injuries. The combined BLS incidence rates for tendinosis and carpal tunnel syndrome in 1999 was one in every two thousand private industry workers. I combined these two categories here because some overlap inevitably exists between them. (Many people with carpal tunnel syndrome also have tendinosis, but they would be counted in the BLS survey only for carpal tunnel syndrome.) In 1999 the median days away from work for repetitive motion injuries was 17, the median days for carpal tunnel syndrome injuries was 27, and the median days for tendinosis was 9.

Although separating the various categories is difficult, the numbers do show that repetitive motion injuries like tendinosis and carpal tunnel syndrome are a significant problem in the workplace. The industry division with the most repetitive motion injuries in 1999 was "manufacturing," and the occupation with the most repetitive motion injuries was "assemblers." The statistics for the years 1992 through 2000 are similar, with tens of thousands of workers getting repetitive motion injuries each of these years (see Table 1 below).

Year	1992	1993	1994	1995	1996	1997	1998	1999	2000
Cases	89875	94308	92576	82625	73796	75188	65866	73195	68323

After 1996, the incidence rate for repetitive motion injuries seems to have dropped slightly (see Table 2 below). The average incidence rate for the period 1992-1995 was 11.4 injuries per 10,000 full-time workers, whereas the average incidence rate for the period 1996-2000 was 8.1 injuries per 10,000 full-time workers. Perhaps efforts to educate workers and employers about RSI and ergonomics have resulted in a slight improvement in the incidence rate. The rate seems to have been holding fairly steady from 1998 through 2000, so we might need greater efforts to try to decrease the rate even further.

Year	1992	1993	1994	1995	1996	1997	1998	1999	2000
Rate	11.8	12.0	11.5	10.1	8.8	8.7	7.4	8.1	7.4

The AFL-CIO states that over 1.8 million Americans suffer repetitive motion injuries on the job each year. This number is so much higher than the BLS estimate of 73,195 that it's hard to explain the huge discrepancy. The AFL-CIO estimate is probably too high because they seem to count all musculoskeletal injuries as repetitive motion/ergonomic injuries (including all back injuries). The BLS estimate only includes those injuries that can be directly attributed to repetitive motion, but the BLS estimate is probably a bit low because the BLS relies on private industry to report the injuries and some under-reporting must occur. Probably the true number lies somewhere between the two estimates, though that leaves a lot of room for disagreement!

Gender Differences in Workplace Injury Rates

Interestingly, the BLS statistics show that although women incurred only about 33% of the total number of injuries in private industry jobs in 1999, they incurred 65% of the total tendinosis/carpal tunnel syndrome injuries and 61% of the total repetitive motion injuries. The incidence rate for these overuse injuries in women is much higher than in men. Part of the problem is that a higher percentage of women than men have jobs that involve repetitive motion. Also, equipment on the job is often sized for the average man's body, which is larger than the average women's body. Therefore, women's ergonomic situations tend to be worse. It's also possible that women's tendons on average have less total collagen and a different collagen composition (higher Type III/Type I ratio), making them more prone to overuse injuries (see The Tendinosis Injury).

A recent study on computer users also found that women were more likely than men to develop repetitive motion injuries.[46] See the section below for more details.

Computer-Related Injuries

A recent study found that computer-related repetitive motion injuries are even more common than previously thought.[46] The study followed 632 newly hired employees who used computers for at least 15 hours per week on the job. For 3 years, the study participants logged their computer usage hours and any symptoms they had. Those who reported symptoms were examined by a physician to diagnose the problem.

Each year, more than half of the study participants experienced neck and shoulder pain, and just over one third of the participants had the neck and shoulder problem develop into a disorder involving impairment or some loss of function. Hand and arm pain was experienced by 39% of the study participants each year, and 21% of the participants had the hand/arm pain develop into a full-blown disorder. Women were more likely than men to sustain injuries. Only about 1% of the study participants developed carpal tunnel syndrome in their first year on the job. The most common hand/arm injury was what the study called de Quervain's tendinitis.

Given these results, you should be especially careful if you use computers 15 hours or more per week. Be sure to use good preventative measures, and be alert for symptoms. You can find lots of information on RSI prevention in the websites given on the RSI Groups and Links page.

Sports Injuries

The article Overuse Tendon Injuries: Where Does The Pain Come From? states that 30-50% of all sports injuries are overuse tendon injuries. I'd like to get more specific numbers, if possible. I'd like to find out the number of tendinosis injuries that occur in recreational and professional sports each year. If you can help me locate this information, please send me email.