Hand safety is always a top concern. But hand injuries need not be sudden or traumatic. They can happen over time and are just as likely to occur at a keyboard or cash register as at a grinding wheel.
Long-term hand injuries are also just as likely to cause permanent damage. It’s important to know how to recognize and prevent them.
“Any type of injury, especially with the hands, can be quite debilitating,” says Janet Craik, director of professional practice for the Ottawa-based Canadian Association of Occupational Therapists.
“Imagine holding a pencil, typing, all types of things you use (your hand for) and not being able to use your thumb against the middle finger. These injuries can affect many areas of a person’s life,” she says.
The most common causes of hand injuries are repetition and overuse, along with awkward positioning of the wrist and fingers, says Dhananjai Borwankar, technical specialist with the Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton. Contact stress — resulting from leaning on elbows at a desk, for example — may also lead to problems.
In industrial settings, heat, cold and vibration from electric or pneumatic tools, such as chainsaws, air hammers or jackhammers, can be harmful. Using too much force while gripping can also put stress on delicate areas of the hand, such as the palm.
According to Health Risks from Hand-Arm Vibration, a publication by St. Michael’s Hospital Occupational Health Clinic in Toronto, regular exposure to vibration can cause permanent injuries to the hands and arms, including damage to the blood circulatory system, sensory nerves, muscles, bones and joints. Carpal tunnel syndrome is caused when tendons in the carpal tunnel, a structure of bone and ligament in the wrist, become swollen and push on the median nerve, a small nerve that controls movement in the hand, Borwankar says.
Symptoms include pain, pins and needles, numbness and loss of dexterity in the fingers, particularly the index finger and thumb.
Carpal tunnel syndrome affects many types of workers, including textile workers, farmers, assembly line workers, mechanics, gardeners, painters, computer keyboard users, food processing workers and cashiers, according to CCOHS.
The pain is especially bad at night, Craik says, a result, experts believe, of a person’s tendency to curl up the hands while asleep. Occupational therapists often provide wrist splints for patients to put on before bed.
“A splint keeps their hands in this neutral position, where their wrist is neither flexed nor extended,” she says.
“The splint can alleviate some of the pressure on the nerve, which then eliminates the pain and the numbness. And if we eliminate the compression, we can eliminate some of the long-term nerve damage, which then causes weakness in the muscles of the hand,” Craik explains.
At work and play
Hand injuries are not just work-related problems, Craik says. An occupational therapist may visit a person’s workplace and home, assessing how activities are performed and how work or recreational areas are physically organized. All kinds of activities, from sports to caring for a child, as well as conditions such as arthritis and diabetes — and even pregnancy — can contribute to hand injuries.
“Occupational therapists look at the whole repertoire of daily activities to see if there are any modifications that can be made to minimize the injury and enhance someone’s ability to do what they need to do on the job, at home and at play,” she says.
Ideally, when symptoms of carpal tunnel syndrome become apparent, the worker should stop doing the activity that is causing the problem, says Mike McKenna, executive director of B.C. Construction Safety Alliance in Vancouver.
If that’s not possible, another option is to reduce the harmful effects of the activity by modifying the work cycle.
Instead of spending an entire morning using a jackhammer to break up a concrete section, a worker could spend some time on this task and then switch to another task that doesn’t require use of a vibrating tool, he says. After some time, the worker can again return to the original task.
“When it’s possible in the production cycle of the job to not do all the jackhammering over a continuous period of time, the worker could intersperse the aggravating activity with other types of activities that are non-aggravating throughout the day,” he says.
Alternatively, McKenna says, it may be possible to modify the vibrating tool. Building up the sides of the handle reduces the amount of strength required to grip the tool. Certain types of material used on the grip can help dissipate some of the vibratory energy.
Carpal tunnel syndrome, he adds, is prevalent among construction workers, who spend long periods of time working with the many vibratory tools used in the industry.
“You go to any construction site, and you see the variety of tools that vibrate. It’s quite astounding, everything from drills to equipment that’s used to pump concrete,” McKenna says. “But (whether an injury occurs) depends on the length of time that the worker is exposed to it and also on a genetic disposition developing.”
“You can put two workers together; one would experience symptoms and the other would have none whatsoever,” he says.
Another disorder, tenosynovitis, occurs when the lubricating system that allows tendons to move easily through tendon sheaths breaks down, Borwankar says. The resulting inflammation in the sheath causes pain and difficulty in moving parts of the hand.
Raynaud’s syndrome, or white-finger disease, is caused by use of vibrating tools, which damages blood vessels in the hand and prevents oxygen from reaching the skin and muscles, Borwankar adds. Symptoms include tingling, loss of sensation, weakness and whitening of the fingers. It may produce a prickly feeling, stinging pain or cold in the fingers.
The first sign of a hand injury is often a tingling or pain that occurs during an activity, Borwankar says. As the injury progresses, the injured area feels weak or painful even when work is just starting, and it continues after work is over.
In later stages, even with the hand at rest, the injured area feels weak, may ache or have pins and needles.
“You’re feeling it all the time. This is where it could disrupt your sleep. It could disrupt a lot of functions, including activities during the weekend,” he says.
To prevent hand injuries, Borwankar advises workers to keep elbows down on work surfaces, to keep palms down, wrists straight and to shift position often. Use both hands to do tasks, and grip an object with the whole hand, not just fingers. Try to avoid applying pressure to a tool with the palm.
“Sometimes, people use their hand as a hammer. That’s one of the worst things you can do,” he says. “The median nerve ends in the centre of the palm, and that’s a very delicate, sensitive area.”
Workers using vibrating tools can protect their hands by setting the tool to a lower speed (without increasing the job’s duration) and using as loose a grip as possible, Borwankar says. Maintaining tools regularly reduces vibration, and wearing gloves that limit the transmission of vibrations also helps.
Workers, he adds, should also use mechanical aids to grasp things, as well as tools with spring-loaded handles and shock-absorbing mechanisms. Gloves made of natural rubber or PVC (polyvinyl chloride) will make gripping easier.
They should avoid putting arms and wrists in awkward positions and try to keep the body and hands warm and dry.
For their part, he adds, managers need to assess a workers’ entire job with a view to addressing the causes of hand injuries, such as repetition, overuse and awkward position. In addition to the workstation and tools, they must also look at what tasks are being
performed, how often and for how long.
Managers should provide tools whose type and design is appropriate to both workers and tasks. Large companies could build a library of tools and equipment — alternative mouse and keyboards, for example — for workers to try out before large purchases are made.
Most of all, Borwankar says, it’s important for workers to be trained on the causes of hand injuries, on how they can protect themselves and on the importance of reporting problems as early as possible.
“At the early stages of an injury, that’s when you need to take action,” he says. “That will allow you to reverse the effects and avoid long-term problems.”
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