Newsletter Sign-up

The proliferation of broadband allows users to move data across more networks. All that motion has made users and employers come to expect the ability to connect from anywhere at anytime. But with this new technology has arisen a particular ergonomic risk factor to the thumbs.

Repetitions and forces are higher than acceptable while using the text messaging functions on wireless devices and are creating a risk factor known as the BlackBerry®thumb based on the ability of users to type much faster by pecking out messages with their thumbs. Many people soon learn to type as many as 40 words a minute.

Importance of the thumb. The hand without a thumb is at worst nothing but an animated spatula and at best a pair of forceps whose points don't meet properly.

The prime importance of the thumb is well-shown in compensation schemes for its injury. In AD 616, King Aethelbert in England established the equivalent of a 30 percent compensation for loss of thumb but only 10 percent for loss of a finger.

Things are not greatly changed today, although total loss of a thumb now rates as a 40 percent loss of the hand. The total loss of an index or long finger is only 20 percent of the hand.

Doctors say repetitive use may cause arthritis or harm tendons in the thumb. According to the Mayo Clinic's website, "the exact cause of thumb arthritis, as with osteoarthritis in general, isn't known. Researchers suspect that it's a combination of factors, including being overweight, the aging process, joint injury or stress, heredity, muscle weakness, and 'cumulative load' to the joint." Cumulative load refers to the repetitive use of the joint.

Painful symptoms may develop. The earliest symptom of joint arthritis is pain with activities that involve pinch grips. When we use handheld communication devices, we grip them. Pain when opening jars, doorknobs, car doors and turning keys are symptoms that might occur after prolonged text messaging or using small devices.

Prolonged or heavy use of the thumb may produce an aching discomfort at the base of the thumb. Changes in the weather may produce similar symptoms. Pinch strength diminishes. Activity-related swelling may develop. Later, any motion of the thumb, even without stress, may become painful.

Eventually, the joint begins to appear enlarged and out of place. This is usually accompanied by limited thumb motion.

Often, the most difficult maneuver is pulling the thumb away from the hand to reach around an object or hold a handheld device. In severe cases, the thumb metacarpal collapses into the palm and other joints may assume an abnormal position to permit a wider grasp.

The thumb is designed to flex and rotate in all directions, and it works differently from the fingers. Thumbs are designed as stabilizers for pinch gripping with a finger. That is why you only have two of them. It is the fingers that have dexterity because the thumbs are not used to repetitive, forceful movements.

Children and teenagers are at particular ergonomic risk because they begin using text messaging devices at an early age and play handheld computer games and video machines. Not only do we not want our children to have the potential for musculoskeletal injuries, but these children are also the employees of the future.

Solutions for employers. A concerned company will train employees about the risk factors and to properly use and key into small devices. Giving employees the anatomical and physiologic body responses is also valuable because they completely understand the risks and their body responses.

Training on overuse syndrome or repetitive motion is important for compliance by the employees. Instead of directing employees to use the communication devices a certain way, giving them the knowledge of what the physiologic problems will present to their bodies and what their injuries can mean for the future is imperative.

Some communication devices are better than others. Those that offer a combination keyboard and touch screen at least give the user choices, so he can rest the other fingers. Stressing error prevention while keying is also important because errors mean employees must redo the characters.

Employees will respond when they believe employers really care about their health and want to provide the best possible information.

Top managers and developers of technology must include ergonomics in the cognitive and user interface functionality and in the beginning of the products' design to ensure a seamless interface and the intuitiveness of the product. Information technology experts assume too much about the anticipated use of the technology by the employees.

Motivating the employees' understanding and appreciation of technology within the overall context of communication and information sharing is important but the most critical issue is the safety and the long-term health of the user.

Hopefully, the tools designed for application of all of these new technologies will be done with people in mind.

By Cindy Roth, Special to the Workers' Comp Forum

Cindy Roth is CEO and chairwoman of Ergonomic Technologies Corp., a worldwide occupational risk management consulting company.

Read more at the WorkersComp Forum homepage.

November 18, 2010

Copyright 2010© LRP Publications