|Sports medicine, orthopedics|
|M70, X50, Z57.7|
|E927.1, E927.3—E927.9, 727.2|
A repetitive strain injury (RSI) is an "injury to the musculoskeletal and nervous systems that may be caused by repetitive tasks, forceful exertions, vibrations, mechanical compression, or sustained or awkward positions". RSIs are also known as cumulative trauma disorders, repetitive stress injuries, repetitive motion injuries or disorders, musculoskeletal disorders, and occupational or sports overuse syndromes.
Repetitive strain injury (RSI) and associative trauma orders are umbrella terms used to refer to several discrete conditions that can be associated with repetitive tasks, forceful exertions, vibrations, mechanical compression, or sustained/awkward positions. Examples of conditions that may sometimes be attributed to such causes include edema, tendinosis (or less often tendinitis), carpal tunnel syndrome, cubital tunnel syndrome, De Quervain syndrome, thoracic outlet syndrome, intersection syndrome, golfer's elbow (medial epicondylitis), tennis elbow (lateral epicondylitis), trigger finger (so-called stenosing tenosynovitis), radial tunnel syndrome, and focal dystonia.
Since the 1970s there has been a worldwide increase in RSIs of the arms, hands, neck, and shoulder attributed to the widespread use of typewriters/computers in the workplace that require long periods of repetitive motions in a fixed posture.
Specific sources of discomfort have been popularly referred to by terms such as Blackberry thumb, iPod finger, mouse arm disease, PlayStation thumb, Rubik's wrist or "cuber's thumb", stylus finger, raver's wrist, and Emacs pinky, among others.
Some examples of symptoms experienced by patients with RSI are aching, pulsing pain, tingling and extremity weakness, initially presenting with intermittent discomfort and then, with a higher degree of frequency.
Causes and risk factors
Workers in certain fields are at risk of repetitive strains. Most occupational injuries are musculoskeletal disorders, and many of these are caused by cumulative trauma rather than a single event. Miners and poultry workers, for example, must make repeated motions which can cause tendon, muscular, and skeletal injuries.
RSIs are assessed using a number of objective clinical measures. These include effort-based tests such as grip and pinch strength, diagnostic tests such as Finkelstein's test for Dequervain's tendinitis, Phalen's Contortion, Tinel's Percussion for carpal tunnel syndrome, and nerve conduction velocity tests that show nerve compression in the wrist. Various imaging techniques can also be used to show nerve compression such as x-ray for the wrist, and MRI for the thoracic outlet and cervico-brachial areas.
The most-often prescribed treatments for early-stage RSIs include analgesics, myofeedback, biofeedback, physical therapy, relaxation, and ultrasound therapy. Low-grade RSIs can sometimes resolve themselves if treatments begin shortly after the onset of symptoms. However, some RSIs may require more aggressive intervention including surgery and can persist for years.
General exercise has been shown to decrease the risk of developing RSI. Doctors sometimes recommend that RSI sufferers engage in specific strengthening exercises, for example to improve sitting posture, reduce excessive kyphosis, and potentially thoracic outlet syndrome. Modifications of posture and arm use (human factors and ergonomics) are often recommended.
Although seemingly a modern phenomenon, RSIs have long been documented in the medical literature. In 1700, the Italian physician Bernardino Ramazzini first described RSI in more than 20 categories of industrial workers in Italy, including musicians and clerks. Carpal tunnel syndrome was first identified by the British surgeon James Paget in 1854.
The Swiss surgeon Fritz de Quervain first identified De Quervain’s tendinitis in Swiss factory workers in 1895. The French neurologist Jules Tinel (1879–1952) developed his percussion test for compression of the median nerve in 1900. The American surgeon George Phalen improved the understanding of the aetiology of carpal tunnel syndrome with his clinical experience of several hundred patients during the 1950s and 1960s.