Research into the causes and treatment of repetitive strain injury is urgently needed for the millions of sufferers worldwide, say experts.
Taking regular breaks from repetitive tasks may help
Decades after RSI was first reported, evidence is still lacking to guide diagnosis and care, The Lancet reports.
Unless clear definitions and evidence of effective treatments are found, RSI will remain controversial, says Dutch author Professor Maurits van Tulder.
RSI is an umbrella term for disorders that stem from repetitive movements.
Several countries report statistics showing that RSI affects 5% to 10% of the population.
For some occupations, such as dressmakers and secretaries, this goes up to 40%.
According to the Chartered Society of Physiotherapy, almost 450,000 UK workers have upper limb RSI.
And between 2003 and 2004, about 4.7m work days were lost to RSI, as workers took an average 18 days sick leave.
Many cases of RSI involve painful hands, wrists, arms, shoulders and neck, and are associated with modern desk work involving computer equipment such as keyboards and mice.
While there are theories as to how these conditions develop, none are supported by strong scientific evidence, and diagnosis is difficult.
Some experts have suggested that the continuous contraction of muscles from repetitive movements can result in disrupted local blood circulation, or that pain sensors in the muscles could become over-sensitive.
Doctors are also struggling when it comes to appropriate treatments - although several studies have shown exercise to be beneficial for symptom relief.
Treatments such as massage or the use of ergonomic keyboards are often recommended, but researchers trying to verify that they worked found they did not reduce sick leave in people who used them.
Professor van Tulder, who looked at the available evidence on RSI to date, explained: "No gold standard tests for RSI exist. Strong recommendations for any therapeutic intervention cannot be made at present.
"The disorder will remain controversial until high-quality trials provide clear definitions of repetitive strain injury and evidence of effective treatments."
A British expert, Professor Peter Buckle from the University of Surrey, said that there was an urgent need for more research.
He said: "Given the prevalence in the working population, it's disappointing we have such a paucity of high quality evidence about diagnosis and treatment."
Many organisations were blind to the fact that they had massive problems with RSI," he added.
He advised: "Often when people are finally diagnosed with RSI their condition is often much worse, so it is important that people not only try to prevent it happening in the first place, but also consult a doctor as early as possible.