BLACKBERRIES: These types of handheld devices are fun, compact, and help you work on the go. But sometimes they come with a price – and we’re not talking about the cost of purchase. Instead, there have been a growing number of orthopedic complaints afflicting PDA addicts.

The 8 million users face a malady no one projected when the device was invented … thumb problems. Call it “BlackBerry Thumb,” a combination of thumb pain and problems with motor function.

You see it all the time: professional types crumpled over those plastic devices, struggling to type on those small buttons. You might even be one of those people in near-fanatic communication with home offices, soccer moms and soccer dads, and kids at college.

You need your thumbs. You need your PDA. But by using the device incorrectly (say, by moving your palms together over the bottom third of the device), you can strain the tender tendons that run from the thumb to the wrist. It’s easy to see how this might happen; most PDAs have tiny keys scrunched together, with little room for palms.

Happily, the solution for the addict is simple, as Dr. Michelle Carlson – a surgeon at New York’s Hospital for Special Surgery – can attest. HSS has seen several cases of the malady each month, and it expects to see many more. The advice from HSS and Carlson is clear, if a bit tricky. But if you start doing it very soon, you could avoid your own case of BlackBerry Thumb.

“You want to get the tendons as straight as possible, so they have the least strain on them as possible,” Carlson says. “That means that your palms should not touch, and your wrists should also be apart.”

That said, this advice is hardly foolproof.

“Some people can do everything wrong and never have a problem; some can do everything right and have a problem,” adds Carlson. Still, there’s hope. Carlson suggests a combination of rest, anti-inflammatory medicine, topical pain products, and a splint. That should be enough to keep the “crackberry addicts” away from pain and trouble. For the 8 million, and those to join them shortly, it’s solid advice.

Dr. Rock is the director of the Non-surgical Foot and Ankle Service at the Hospital for Special Surgery in New York. Reach him at drrock@nypost.com.