Musculoskeletal Disorder: Keyboard- related MSD

Musculoskeletal disorder is very much related to computer keyboard usage. Computers are ubiquitous in our society, with 100 million computers estimated to be in use in the United States in 2000. Except for rare cases, every computer has a keyboard for text and data entry.

The occupational risk factors of musculoskeletal disorder (MSDs), such as carpal tunnel syndrome and tenosynovitis, are thought to be due to excessive use (up to 100,000 keystrokes per day) and due to the use of deviated wrist postures.

An extensive review of the literature on the association between keyboard usage and prevalence of musculoskeletal disorder showed that the prevalence of keyboard-related musculoskeletal disorders among computer users.

Based on symptoms of musculoskeletal disorder or physical examination findings, ranged from 9% to 50%, as compared with 4.5% to 17% among reference groups who were exposed to low levels of or no keyboard work.

Compared with findings for a reference group, the odds ratios for keyboard-related musculoskeletal disorder among computer users were from 0.5 to 9.9 for the neck and shoulders and from 0.7 to 10.1 for the hand, wrist, or elbow.

As compared with findings for a reference group, suggest that computer keyboards may contribute to musculoskeletal disorder affecting the upper extremities. The keyboard slope is the angle of the plane of keytops to a horizontal.

A typical conventional keyboard has a built-in slope of about 6 degrees. We have shown that changing the slope of the keyboard in a downward direction can change wrist extension angle and not impair typing speed and accuracy.

Wrist extension angle decreased 1 degree for every 2-degree decrease in keyboard slope angle as the keyboard was positioned at 15 to -15 degrees of slope. Mean wrist extension angle decreased to less than 15 degrees when the keyboard was positioned with a slope of 0 degrees or lower.

In theory, wrist extension angles close to the anatomical neutral position (compared with large wrist extension angles) result in less risk of distal upper-extremity musculoskeletal disorder because the pressure in the carpal tunnel is lower and forces pressing against the median nerve and flexor tendons are less.

Positioning a computer keyboard with a downward slope reduces wrist extension needed to use the keyboard and has been shown to decrease pressure in the musculoskeletal disorder like carpal tunnel.

Musculoskeletal Disorder Treatment - Extracorporeal Shock Wave Therapy

These are conditions that are difficult to treat musculoskeletal disorder with standard conservative measures, such as physical therapy and local injections; in such cases this Extracorporeal shock wave therapy is useful in treating musculoskeletal disorder.

A single session of high-energy Extracorporeal shock wave therapy in patients with chronic shoulder pain caused due to musculoskeletal disorder and calcification of the rotator cuff brings significant functional and radiographic improvement along with markedly diminished pain.

Extracorporeal shock wave therapy stays affective in curing musculoskeletal disorder. Here's a look at how the therapy works on a deposit in the rotator cuff.

Primary effect: Acoustic waves break up the calcification deposit.

Secondary effect: Cavitation wears away calcification.

1. Gases within the cells condense and form microbubbles.
2. The microbubbles grow in size up to three times larger than the nucleus
3. The microbubbles burst into troy jets of fluid that reach speeds of 100-800 m/sec, breaking up the calcification and further dissipating it. Energy released by the bubbles also creates a secondary shock wave.
4. Waves hitting the posterior border of the deposit are deflected, resulting in strong tensile forces that also break up the deposit. The waves do not penetrate the bone.