Speaking to BBC News, Sean Hughes, professor of orthopaedic surgery at Imperial College London, explained that the thumb works differently to fingers.
"The thing is the thumb is designed to flex and rotate in all directions," he said. "The joint at the bottom of the thumb allows it to move like this and tapping away could cause it to become sore."
Users of Blackberry-type devices tend to hold the device in their fingers and press the tiny keys with their thumbs. This reverses the normal position, where clumsy thumbs are relegated to the space bar and let fingers do the typing.
Unlike texting, where only a few words are normally typed at one time, BlackBerry users may send lengthy e-mails.
Speaking to health information site WebMD, hand surgeon Prosper Benhaim MD, associate professor of orthopaedic and plastic surgery at UCLA, agreed that "anything that causes repeat motion can predispose someone to injuries of various sorts, whether it is tendinitis or aggravating underlying arthritis."
The recommendation from Dr Benhaim is generally to rest the thumbs and to use a normal keyboard for typing longer messages.
Neither Professor Hughes nor Dr Benhaim have actually come across any cases of Blackberry thumb to date.
Employers should be aware of their potential liability for failing to deal with Repetitive Strain Injury (RSI) in the workplace.
A few years ago, a court ordered Barclays Bank to pay compensation of £244,000 to a former employee who was forced to give up work as a result of pain in her right hand. Fiona Conaty had worked as a bank clerk and argued that a defective work station caused her to carry out keyboard work with an unsuitable posture.
Her symptoms developed over two years, after which time Miss Conaty was unable to tie her shoes or even comb her hair. She was only 28 years old at the time of the case.