Overuse Phenomena and RSI

Synonym: Cumulative trauma disorder

Overuse phenomena are usually seen in the wrists and hands. Cumulative microtrauma causes tendonitis (inflammation of the tendons) and tenosynovitis (inflammation of the tendons and synovial sleeve). When tenosynovitis is the result of repetitive movements (e.g. using a keyboard) the condition is called repetitive strain injury (RSI).

The mechanisms involved in the production of the 'inflammation' associated with cumulative trauma are not clearly understood but many factors have been implicated including mechanical fatigue involving ligaments, tendons and soft tissues, Damage to neural tissue from ischaemia has been mooted, as has damage to muscle tissue relating to adenosine triphosphate (ATP) depletion. Psychosocial factors also seem to play a part, particularly in RSI.¹

The exact incidence of overuse phenomena is unknown because the condition has not been clearly defined. However, several long-term, retrospective, work-related studies have estimated the annual incidence of upper extremity disorders at 4.5-12.7% per year.¹

Risk Factors

Several occupations have a high incidence of overuse injury including ultrasonographers, assembly line worker, tailors, surgeons, dentists, nurses and anyone involved with heavy computer work. Associated sporting activities include equestrian athletes, swimmers, golfers and martial artists.¹

History

The presenting symptoms depend on the site of the inflammation and various syndromes have been reported. All have in common pain as the primordial feature. A careful history should be taken to identify any aggravating or relieving factors. The patient may have already identified an occupational or leisure-related activity that brings on the pain. Associated symptoms may include clicking, popping' or rubbing of a tendon, or overlying erythema.

Examination

Examination findings will depend on the underlying condition and cause. Commonly, swelling, erythema and tenderness may be found over the affected tendon. Crepitus may be demonstrated on movement, and the range of motion may be found to be limited on active and passive movement of the relevant joint.

Depending on the site of inflammation, the following may need to be considered:

• Achilles tendon injuries and tendonitis
• Acromioclavicular degeneration (e.g. acromioclavicular joint injury)
• Ankle degeneration
• Anterior cruciate laxity (e.g. anterior cruciate ligament injury)
• Carpal tunnel syndrome
• Elbow degeneration (e.g. elbow and forearm overuse injuries)
• Gamekeeper's thumb
• Knee degeneration
• Neck pain
• Pronator teres syndrome
• Shin splints
• Suprascapular nerve compression
• Supraspinatus tendonitis
• Tarsal tunnel Syndrome
• Tibialis anterior tendinopathy
• Tibialis posterior tendinopathy

The diagnosis is usually made clinically, but investigations may be contributory in certain situations.

Laboratory Studies

These are rarely helpful, although inflammatory markers and autoantibody screening may be helpful in excluding systemic joint conditions.

Imaging

Imaging is not performed on most patients, unless surgery is being considered, in which case it is vital to support the diagnosis.

• Radiography This may show bony avulsions, stress fractures, cartilage atrophy or calcification of a tendon.
• Bone scanning This is sometimes required to reveal stress fractures.
• MRI This may contribute in a variety of ways, demonstrating damage to muscles, tendons and ligaments, although it is more specific in acute than chronic injury. It may demonstrate bone marrow oedema associated with stress fractures, and may also assist in the diagnosis of nerve compression syndromes.
• Electromyelography (EMG) and nerve conduction studies These may be helpful in diagnosing peripheral nerve compression or injury.

Non-Drug

• Physiotherapy The role of the physiotherapist in these conditions is to institute a regime which rest the affected part whilst encouraging non-painful exercises which prevent restriction of movement. Other modalities used include transcutaneous nerve stimulation (TENS), ultrasound, and inferential treatment. The patient should be encouraged to avoid any activity or movement which is a clear aggravating factor.
• Occupational Therapy Occupational therapy can help to modify the workplace to prevent the condition from recurring (see Prevention, below).

Drug

Non-steroidal anti-inflammatories are useful in reducing musculoskeletal inflammation. Recent evidence suggests that simple analgesics may work equally well.⁵ Other treatments that may be of benefit include muscle relaxants and tricyclic antidepressants. Corticosteroid injections, sometimes in combination with local anaesthetic, are beneficial in treating local tendonitis or tenosynovitis.

Surgery

This may be indicated when conservative treatment fails, to decompress nerves or repair ligaments. Surgery should only be undertaken if a specific diagnosis has been established, not simply because pain has persisted despite medical treatment.

Controversies concerning RSI^1,6

Diagnosing a patient with RSI has always been a controversial issue, not least because of the litigation issues surrounding action against an employer. Psychological factors would appear to play a part, and stress at work is a known aggravating factor. Many authorities recommend diagnosing RSI only in the presence of consistent subjective symptoms, demonstrable gross and microscopic pathological features, and appropriate responses to therapy. This leaves a large section of patients who have a rather vague unclassified condition which would not fit these criteria.

Complications are mainly iatrogenic, arising from adverse effects of drugs and infection or bleeding after surgery.

Most injuries recover after three to six months. However, recurrences are common unless the original aggravating factor is removed.

This involves minimising the overuse or repetitive microtrauma, and reducing exposure to force, vibration and repetitive movement. Occupational therapists can be helpful here. Often, simple modifications are sufficient. Occupational therapists are often called upon to advise employers about wider scale changes to reduce the risk of workforce injury in the commercial sector.