Repetitive Strain Injury – Causes, Symptoms and Treatment

Repetitive strain injury or RSI is a term describing the conditions where symptoms develop due to build of damage over the period, owing to repetitive motion.

To say some person has repetitive strain injury or repetitive stress injury, other pathologies should not be present and the pain complaints can be related to repeated activities over a period of time.

Repetitive strain injuries are also known as cumulative trauma disorders because the issue damage gets added from repetitive demand over the course of time.

The term includes a lot of disorders which could be occupational, recreational, and habitual activities.

The recent surge of gadgets has led to a rise in RSIs.

Few common examples of repetitive motions are

• Typing
• Grasping tools
• working on an assembly line
• Sports training
• Continuous mouse use
• playing games on computer or phone or tablet
• Using vibrational tools

Most of RSIs are know to affect upper extremity.

The estimated annual incidence of upper extremity disorders at 4-15% per year.

RSI was first described by Bernardino Ramazzini, in 1700.

Examples of repetitive strain injury are

• Tendinosis
• Carpal Tunnel syndrome
• De Quervain syndrome
• Thoracic outlet syndrome
• Tennis elbow
• Golfer elbow
• iPod finger
• PlayStation thumb
• Rubik’s wrist or cuber’s thumb
• Stylus finger

Other names for repetitive strain injury are

• Repetitive stress injury
• Repetitive motion injuries
• Repetitive motion disorder
• Cumulative trauma disorder
• Occupational overuse syndrome
• Overuse syndrome
• Regional musculoskeletal disorder

Causes of Repetitive Strain Injury

• Overuse of particular muscle or group
• Use of vibrational tools
• Poor posture
• Forceful exertions
• Carrying heavy loads
  • Carrying heavy school/laptop bags
• Stress
• Mechanical compression
• Sustained or awkward positions.
  • Reading books while looking down
  • Use of phone/mobile leaning onto one side
  • Watching TV in incorrect position e.g. Too much to the left/right.
  • Sleeping with head forward, while traveling
• Cyclical activity due to labor specialization

Pathophysiology of Repetitive Strain Injury

The basic cause is an accumulation of tissue stress because of tissues not getting enough time to relax. this leads to mechanical fatigue and that is followed by injury.

Thus, put simply, rate of injury simply exceeds the rate of adaptation and healing in the tissue.

Chemically, the tissues subjected to repetitive stress show altered levels of prostaglandin E2 and nitric oxide.

Clinical Presentation

Exact symptoms of overuse injury or repetitive stress injury would depend on the region involved and forces involved.

Major complaint usually is pain followed by stiffness in the involved muscle or region.

The often involved regions are the arm, back, shoulders, wrists, hands, or thumbs that worsens with activity.

Sports-related injuries involve the lower limb.

There are activities that worsen the pain. The patient may complain of weakness and lack of endurance.

The physical examination discloses only tenderness and diminished performance on effort-based tests.

DX-rays and electrophysiological studies are normal.

The patient should be enquired about the occupation in detail, posture habits, and any unusually repeated activity\

Differential Diagnoses

• Acute injuries
• Infection
• Inflammatory diseases

Diagnosis

The lab work is often normal. So are x-rays and other images.

Nerve conduction studies and electromyography can reveal the of peripheral nerve compression or injury to know about the location and severity of the injury.

Treatment of Repetitive Strain Injury

Activity Restriction/Modification

The part affected needs to be rested so that it could get enough time to repair itself. This can be done either stopping the activities of the part altogether or if feasible, modification of the activity.

Splints, when chosen properly,  can help in activity restriction.

Drugs

Drugs for pain like NSAIDs are mainstays in the treatment. Muscle relaxants, opiates, corticosteroids, tricyclic antidepressants, and sleep medications have a role too.

Local Heat or Cold

Applying heat or cold over the painful area is known to soothe.

Steroid Injections

These are frequently used in the treatment of repetitive strain injuries. Steroid injections under ultrasonographic control increase accuracy and decrease the possibility.

Physical Therapy

• Supervised use of the injured part
• Transcutaneous electrical nerve stimulation or TENS
• Ultrasound therapy
• Iontophoresis [techinque that applies current on the surface ]
• Heat/cold application
• Proper training and equipment to prevent further injury

Surgery

Surgical intervention is undertaken if conservative approaches fail and if the injury is amenable to surgery. The surgery usually involves, decompression of nerves and repair of lax or failed ligaments.

Prevention of RSI

Because repetitive strain injuries are caused by repeated activity, the key to prevention is to break the repetitive damage by frequent breaks. Reduction of the activity’s impact can be achieved by reduction of the intensity of the activity.

Following measures are aimed at this objective

• Taking frequent breaks
  • For example look away from the screen for relaxing eyes
  • Standing up and stretching frequently between job activities
• Maintain a good general health
  • Healthy eating to avoid deficiencies
  • Regular exercise for better muscle endurance
  • Quit smoking for better blood flow and repair capacity
• Following Desk Job Ergonomics
  • Ergonomic desk, chair, and screen
  • Avoid slouching and keep an erect posture
  • Posture: To avoid slouching, keep the ears and back in a straight line with the pelvis.
  • Do not bend wrists while typing
  • Do not hit the keyboard with force to avoid finger injury
  • Do not grip the mouse too tightly
  • Wear headset for a phone conversation, if calling is part of the job
• Stress management techniques and coping skills
• Better equipment and terrain training for sports

Prognosis

Most repetitive strain injuries resolve after 3-6 months.

Recurrence is common when the  offending cause is not removed.

Recovery after surgery varies with the procedure.