Dec 2015 05

Candy Crush thumb

By: Dave Wheeler

In April this year, the Journal of Internal Medicine, JAMA, published research describing a man who'd ruptured a tendon in his thumb playing Candy Crush.

A man from California played Candy Crush Saga using his left hand all day for 6 weeks (while using his right hand to carry on with the rest of his life).

The repeated movement of his thumb tapping on the touchscreen for such an intense period caused a tendon to rupture.

The rupture was so severe that the man was then unable to move his thumb at all. 

This is an extreme example of a repetitive strain injury (RSI) of the muscles of the thumb, which have become increasingly common in the last 15 years.


Blackberry thumb - it's a lifestyle thing

Blackberry email pagers were introduced in 1999 and quickly became a hit with on-the-road business people. Blackberry's morphed into the first smartphones, even if youngsters today think that those were invented by Apple & Samsung.

The use of the thumb to type on a small keyboard or touchscreen has been around now for about 15 years, and has some consequences. After all, the thumb, although quite mobile, is really pretty clumsy and is actually designed to stabilise when pinch-gripping with fingers. 

So using the thumb to do all the hard work and finesse of texting on a small screen keyboard is asking a bit much.

Think about a traditional computer keyboard - it's the fingers that do all the quick, hard strikes on the letter keys... the thumb is reserved for the odd blunt strike on the space bar. This is a job that the thumb's suited to.

So continuous texting, mailing or playing games on your phone with your thumb is using certain muscles in a way that they're not really meant for.

The 2 muscles that tend to get over-used are:

  • abductor pollicis longus which moves the thumb away from the other fingers.
    • ‚Äčabduction is the movement of the thumb away from the rest of the hand;
    • the polllicis is the thumb.
  • extensor pollicis brevis which lies next to abductor pollicis longus and pretty much just assists it.

Over-using these muscles causes them to bulk up significantly. That bulking up affects the tendon of the muscle too. When those tendons become too big for the sheath that surrounds the muscle, it starts to rub against the sheath causing inflammation and pain - in other words tendinosis - this is classic RSI.

Blackberry Thumb is known by other names, too:

  • Gamer's thumb
  • Texting thumb
  • Nintendonitis
  • Trigger thumb
  • iPhonitis
  • De Quervain syndrome

It's not just avid texters who can suffer with an inflammation of the abductor muscles of the thumb - pianists, too, can suffer.

To treat blackberry thumb:

  1. Stop texting with your thumb
  2. Use ice to bring down inflammation of the muscle and tendon
  3. Get yourself treatment from a remedial massage therapist or physio

As ever, if you think I can help, give me a call.