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Occupational overuse syndrome (OOS)

Occupational overuse syndrome is an umbrella term for a range of conditions which cause discomfort or persistent pain in muscles, joints, tendons, nerves and soft tissues. These conditions develop as the result of a number of factors such as repetitive movement, constant muscle contraction or straining, forceful movements and constricted postures.

Occupational Overuse Syndrome (OOS) was previously referred to as Repetitive Strain Injury (RSI) and is one of a number of conditions increasingly referred to as Gradual Process Injury (GPI). 
 
New Zealand's Accident Compensation Corporation defines GPI as changes that result in a personal injury that develop slowly and progressively over time, such as the effects of exposure to noise or fumes at a workplace or an activity you carry out in the course of your work.
 
 

Signs and symptoms

Symptoms tend to develop gradually and worsen over time if left untreated. Symptoms mainly occur in the shoulders, arms and hands. Early symptoms of OOS include:
 
  • Muscle discomfort
  • Aches and pains
  • Hot or cold feelings
  • Muscles tightness and spasms
  • Numbness and tingling.
There may be associated symptoms of tiredness, headaches, anxiety and loss of concentration. As the condition progresses the pain and discomfort may become constant, there may be a loss of muscle strength, burning sensations in the tissues, and sleep disturbances.

There are many different conditions that can fall under the umbrella of OOS. These can be broadly classified by the nature of the condition. The three main categories are:

Localised inflammations
Where pain and inflammation occurs in a localised area. These conditions can usually be easily treated and recovery is usually quick. Examples of localised inflammations include tennis elbow (inflammation of the tendons on the outside of the elbow joint) and rotator cuff syndrome (inflammation of the tendons around the shoulder joint).
 
Compression syndromes
Where swelling in the muscles and soft tissues compresses the nerves. Pain tends to be more widespread, treatment is more involved and recovery can take several weeks. An example of a compression syndrome is carpal tunnel syndrome, where the median nerve in the forearm is compressed as it travels through the wrist.
 
Pain syndromes
These are much more complex conditions that develop over a period of time. Pain is persistent and widespread and is often associated with emotional symptoms such as depression and anxiety. Treatment is difficult and recovery takes months or years. An example of a pain syndrome is fibromyalgia – where pain trigger points develop in the muscles and soft tissues.
 
 

Causes

There are a number of causes for OOS. Essentially, however, any repetitive work practice or activity that causes the muscles to be held tight and tense for long periods can lead to the development of OOS.

Muscles use energy supplies derived from the blood to function. The blood is supplied to the muscles via small blood vessels that travel through the muscles.  When the muscles are tense these blood vessels are constricted, slowing the flow of blood.  If the blood flow is restricted for too long, the muscles work inefficiently.  This uses energy very quickly, tires the muscle, and leads to a build-up of acid waste products.  This causes pain and the muscle stiffens, making it harder still for the muscle to work.

The muscles and tendons can withstand fatigue and are able to recover if their movements are varied and they are regularly rested. If “overuse” occurs the muscles and tendons may be strained beyond their capacity.
 
Factors that can lead to OOS developing include:
 
  • Awkward or constricted postures.
  • Repetitive movement.
  • Prolonged muscle tension.
  • Forceful holding or movement.
  • Poor ergonomics.
  • Poor work practices eg: poor time management, poor work techniques, lack of training.
  • Psychosocial factors eg: excessive workload, deadlines, social and physical work environment.
 

Treatment

Diagnosis of OOS is often difficult. It is important for the doctor to take a full medical history and conduct a physical examination. Other causes for the symptoms need to be ruled out.

Once a diagnosis of OOS has been made, and the specific OOS condition has been identified, appropriate treatment will be recommended. This may involve referral to an occupational or musculoskeletal specialist and may involve input from healthcare professionals such as occupational therapists and physiotherapists. Treatment may include:
 
  • Rest from activities
  • Changing work practices
  • Postural correction
  • Physiotherapy
  • Pain relieving and anti-inflammatory medications
  • Exercise and stretching
  • Relaxation exercises
  • Additional treatments that may be recommended include massage and acupuncture.
It is important to follow a tailored, individual treatment programme to achieve best results.
 
 

Prevention

There are a number of steps that can be taken to prevent OOS. The Occupational Safety and Health division of the Department of Labour highlights five main ways to prevent OOS in the workplace:
 
  • Design equipment and tasks with people in mind eg: ergonomic workstations.
  • Organise a reasonable workload.
  • Pay attention to work environment eg: good lighting.
  • Train and educate all staff.
  • Use safe work methods.
  • The following general factors play an important role in OOS prevention:
  • Stop activity when discomfort is felt.
  • Maintain correct posture.
  • Take regular breaks.
  • Exercise regularly.
  • Maintain a good level of general fitness.
  • Maintain a healthy balanced diet.
  • Manage stress levels.
  • Don’t smoke.
  • Avoid prolonged, repetitive movement or activity.
  • Educate yourself about OOS prevention.
If OOS is suspected, is it important to seek early treatment to prevent the condition progressing.
 
 

Support and information

Occupational Safety and Health Service (OSH) provide workplace assessments and advise on prevention of OOS in the workplace.  The Department of Labour and Accident Compensation Corporates (ACC) websites also provide information about Gradual Process Injury in general. 
 

References

Accident Compensation Corporation (2011) Discomfort pain and injury. www.acc.co.nz/preventing-injuries/at-work/workplace-health-issues/PI00082#P4_347

Anderson, K. N., Anderson, L. E. & Glanze, W. D. (Eds.) (2006) Mosby’s Medical, Nursing and Allied Health Dictionary. (6th ed.) St. Louis: The C.V. Mosby Company
 
Occupational Safety and Health Service, Department of Labour. Guidelines for the Prevention and Management of Occupational Overuse Syndrome. Wellington www.osh.govt.nz/order/catalogue/79.shtml
 
Last Reviewed – 15 March 2013 

 

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