Also called cumulative trauma disorders (CTD), repetitive trauma, repetitive injury, RSIs refer to a range of disabling injuries of the soft tissues, usually of the hands, wrists, forearms, shoulders, back and legs. The different terms indicate that such injuries involve repetition, and that they can also be caused by force, rapid movement, excessive strain, uncomfortable positioning of limbs or being in a constrained position over long periods. The condition should actually be called "Occupational Overuse Syndrome" (OOS) to emphasize, that for the majority of people at least, the condition is work related. Although RSIs are commonly thought of as affecting only the upper extremities there are a number of conditions resulting from occupational overuse which affect the upper and lower back, legs and knees.
Repetitive strain injuries defined
Repetitive strain injuries are a family of injuries affecting tendons, tendon sheaths, muscles, nerves and joints in the arms, hands, shoulders, neck, upper and lower back, and the legs. RSIs cause persistent or recurring pain in the affected areas, and if left untreated, can seriously impair the functioning of the involved body part.
Who is at risk
Repetitive strain injuries were, in the past, usually associated with sports, which is why they are referred to as "tennis elbow" or "golfer's elbow". Very often workers did not associate these conditions with their work, therefore the RSIs were not attributed to the work a person did, although certain conditions, such as "weaver's cramp", "threader's wrist", or "carpet layer's knee" were reported. Today, RSIs are increasingly common among a variety of workers: clerks, jackhammer operators, typists, maintenance workers, all can be victims of their occupations. For some reason they affect women more often than men. This can partly be explained by the fact that more women are employed in work which involves repetitive hand movements, such as word processing, electronic assembly, and manufacturing. In addition, women are often expected to work with standard hand tools and gloves that are too large for them, because they are made for the average worker, usually a man.
Many workers are still not familiar with the origins of repetitive strain injuries, so everyday aches and pain is often overlooked, and no connection is made between the injury and the workplace. Aches and pains are the body's warning signs that a serious injury may be developing, and we should listen to our bodies. If the causes are not eliminated, or the worker not removed from the cause, the damage can be permanent and irreversible.
Among some of the PSAC members at risk there are: meat handlers and inspectors, mail sorters, data entry clerks, word processors, carpenters, truck drivers and others occupations which demand the same repetitive motion over long periods of time. This type of work, especially when combined with awkward and unnatural body postures, or having tin use excessive force, places undue pressure on parts of the body, resulting in injure to the affected part.
The number of RSIs is increasing, yet to this day there are still no Canada wide regulations or standards covering them.?Some provinces, notably British Columbia, have legislation covering ergonomic issues.
Causes of Repetitive Strain Injuries
In general, repetitive strain injuries are caused by a combination of?high force, awkward posture, and high repetition or prolonged static postures.?Ergonomists believe that one of these factors alone is unlikely to present a significant risk of injury. They believe that two or more risk factors are needed to cause injury. Nevertheless, if even one of these risk factors is present, preventive measures, as described below, should be considered.
RSIs are caused by motions which occur as part of a work process:
Repetitive?rapid?movements of a body part;
Repetitive?forceful?movements of a body part;
Fixed, awkward, unsupported body positions which must be held over long - time periods.
Usually RSIs have multiple causes. A worker who has to work with a screwdriver while working at an unnatural and uncomfortable angle may get RSI from the repetitive use of force while being in an unnatural position. A VDT operator may sit in an uncomfortable position, have no wrist support, and at the same time use rapid finger movements on a poorly designed keyboard. Such persons may develop a number of serious injuries because of the combined effects of such assaults on their musculoskeletal system.
Any work that forces a person into an unnatural position can lead to repetitive strain injuries. Ongoing forceful twisting of a screwdriver, as on a production line, bending of the wrists for long periods, repetitive finger movements without rest, working with arms above shoulder height, having to grip tools forcefully, are all activities which will strain tendons, ligaments and muscles, causing pain and injury.
Other factors which can contribute to repetitive strain injury include excessive work rates, lack of variation in the job, i.e doing the same task over and over, poorly maintained equipment, stress, excessive overtime, vibration and inadequate job training.
Symptoms of Repetitive Strain Injuries
Symptoms can range from a sense of discomfort to excruciating pain in the affected?
body part. General symptoms include:
numbness, tingling, coldness or burning sensations;
dull ache to severe pain; swelling of the affected areas, such as wrists and hands;
clumsiness, loss of strength and agility in the affected part, especially hands;
loss of sensation, especially in the hands.
The aches and pains usually are strongest at night, in fact, that symptom alone is indicative of repetitive strain injury. Pain in one area may radiate to other connecting parts, i.e. pain from the wrist can radiate to the elbow and shoulder. If a worker has any of these symptoms, it should be reported immediately.
Parts of the body that can develop RSIs
The musculo-skeletal system provides strength and support and keeps the body moving. The bones, connected by joints, serve as levers for the muscles to act upon. The muscles are anchored to the bones by tendons. Any activity that puts too much stress on this system can cause an RSI. Tendons are a common site for occupational overuse injuries. They are tough tissues with few nerve endings and little blood supply. They are often found in small spaces and are essential for any body movement. The various names for repetitive strain injuries reflect the fact that different tendons, joints or muscles may be affected by excessive repetitive movement.
The following describes the commonly occurring injuries.
Tendonitis?is an inflammation of a tendon. Tendons are tough elastic fibres which connect muscles to bone and are essential to the proper functioning of all body movements. When inflamed, they are swollen and painful, thereby restricting motion. The thickening tendon can actually lock and prevent movement completely. There are several types of tendonitis.Rotator?Cuff tendonitis affects the tendons which move the shoulders and rotate the arms.?Peritendonitis?refers to inflammation of the area surrounding the junction between muscle and tendon.?Trigger finger?is a thickening of the finger tendons, making it difficult to straighten the finger after bending.
Tenosynovitis?is the inflammation of the tendon sheaths which surround a tendon at the wrists and ankles. The double walled sleeve of the sheath secretes synovial fluid which provides lubrication for the tendon as it moves within the sheath. When the lubrication is depleted due to overuse, the tendon and sheath rub against each other and become irritated and inflamed, causing numbness, swelling, tingling and pain.?De Quervain's disease?is a type of tenosynovitis, more commonly known as?trigger thumb.?It affects the common sheath for the two tendons of the thumb just above the wrist.
Carpal Tunnel Syndrome(CTS)?is?probably the most often cited RSI. It is a painful disorder of the hand, caused by the swelling of the carpal ligaments which form the tunnel through which the median nerve has to pass. This causes compression of the nerve. The median nerve goes from the shoulder and forearm through the tunnel to the hand, sending nerve signals to the first three and a half fingers and to the palm. Repetitive wrist flexing causes the tendons inside the tunnel to swell and press on the median nerve. This produces numbness of part of the hand, along with tingling, pain and clumsiness of the hand. Eventually loss of muscle tissue and loss of hand strength will occur, if left untreated. Diagnosis of CTS is made by certain tests which may reveal damage to the median nerve. Exposure to cold temperatures and the vibration from low frequency hand tools are also associated with the development of CTS.
Epicondylitis,?also known as tennis elbow (lateral epicondylitis) or golfer's elbow (medial epicondylitis), is not only caused by playing tennis or golf. Any repetitive motion of the forearm and elbow, such as hammering, laying bricks or carrying a heavy load with arms extended, over an extended time period will eventually result in an inflammation of the elbow bone where the tendon joins the bone. This puts pressure on the ulnar nerve which leads down the forearm to the fourth and fifth fingers. Hammering especially is known to contribute to epicondylitis.
Back strain?(Truckers' back) is caused by sitting with the small of the back unsupported for a number of hours, while being exposed to the vibration of the vehicle. This position forces the driver to keep the back muscles tight, thereby causing strain in the small of the back. The culprits are the seats in trucks, which are not designed for easy adjustment; most are still bench type seats with little or no support for back and arms, where it counts. The long hours of driving that most long-haul truckers have to do, are also a factor.
Bursitis?is?a painful inflammation of the bursa, which is a fluid-filled fibrous sac often found in areas subject to friction, around joints, for example, or where a tendon passes over a bone. Excessive, prolonged and repeated pressure or jolts to joints can lead to bursitis. Carpet layers' knee, house maid's knee (from long hours spent kneeling during carpet installation or house work), are examples of bursitis of the knee.
Preventing Repetitive Strain Injuries
- The cornerstone of every effective prevention program is to make the job fit the person, rather than make the person fit the job. Any equipment must fit the person using it, all machinery must, where possible, be adjustable to fit persons of different sizes.
- Workers must be trained in the proper use of all tools and equipment, and how to adjust them to their needs. Where possible, all tools and equipment should be redesigned to fit every worker who uses it over and over, poorly maintained equipment, stress, excessive overtime, vibration and inadequate job training.
- Any job requiring repetitive motion must be carefully analyzed through Job Hazard Analysis to determine if there is a possibility for anyone developing RSIs.? If such a possibility exists, provisions for rest periods, job rotation and, where possible, changes to the work process should be made to break up the series of repetitive motions that can lead to injury.
- Job rotation is undoubtedly the most effective RSI prevention method. Throughout the work day, muscles go through cycles of work and recovery. When muscles are used, they contract, and recover when the work is over. Further muscle recovery occurs when the body uses different muscle groups during a new and different task. Ideally, the rotation sequence should progress from light to moderate to heavy work, then back to light work. This allows the operator to gradually work up to the heaavy work, and obtain relief immediately after. Muscle recovery also occurs during regular rest breaks, but with job rotation further muscle recovery occurs, because of the differing muscular requirements.
- A program to investigate and document all complaints of pain related to the workplace must be established. Each case must be analyzed to determine causes and remedial action.
- Regular, scheduled rest breaks should be arranged for all workers who have to make regular repetitive motions during their work.
- Development of an exercise program specific to the type of work being done, will go a long way toward strengthening the muscles which must be used during a work process, thereby preventing the strain and injury of repetitive motion.
- Where possible, tools should be redesigned to fit the individual or a specific task. Some tools can be re-designed with smaller grips, so that they are easier to manipulate. Where feasible, grips should have soft rubber covering to minimize the pressure on the hand tissues during use.
- All tools must be maintained in good working order, so that they move smoothly and with minimum effort. If knives are used, they must be kept sharp so that less force is needed for cutting.
Once a worker has been injured and suffers from RSI, the condition should be reported to the employer, the Workers' Compensation Board and the Workplace Health and Safety Committee (WHSC) and medical treatment be sought. A doctor will often prescribe the RICE treatment (Rest, Ice, Compression, Elevation) during the acute phase. In severe cases a brace may be prescribed. The doctor should be informed that the injury is work-related, and that a WCB claim has been or will be filed.
A request for alternate work should be made to the employer. If time off work is necessary, an application for injury-on-duty leave should be made, where this is part of the collective agreement. A WCB claim should be made in any case, since serious complications could arise later, and WCB needs that information in case they have to deal at that time with an application for compensation.
The workplace health and safety committee has to be informed of the occurrence, so that remedial and preventive measures can be instituted, in consultation between the WHSC and the employer.
Surgery for the RSI should always be the last resort, and the worker my not be able to return to previous duties which caused the injury in the first place. If not, adequate accommodation may be required. There are many documented cases of workers reporting a recurrence of their symptoms when they returned to their old jobs.
In conclusions it has to be reiterated that RSI’S can and must be prevented, if for no other reason than that they cause needless pain to a great many people. It is also much easier to prevent the condition than to cure it. A job employers need further reasons to prevent RSI’s, they should consider how much money they can save in compensation costs, time off work and absenteeism, if they prevent workers from developing RSI’s.
For more information, contact your?จุดอ่อนบาคาร่าPSAC Regional Health and Safety representative,จุดอ่อนบาคาร่าyour Component?or the?PSAC Health and Safety Section.