Knuckle study cracks new ground

Despite what your mother may have warned, the onnoxious habit of cracking your knuckles may not lead to arthritis.

A California doctor, Donald Unger, conducted some hands-on research, 50 years of it, about the topic. Unger popped the knuckles of his left hand at least twice a day, leaving his right hand as a control.

“Thus, the knuckles on the left were cracked at least 36,500 times, while those on the right cracked rarely and spontaneously,” he wrote in a letter to the editor in the journal Arthritis &Rheumatism in 1998.

Unger’s data set showed no arthritis in either hand and no apparent differences between the two hands, a finding that earned him the 2009 Ig Nobel Prize in Medicine, a Nobel Prize parody.

A slightly larger — and more rigorous — 1990 study by Detroit researchers found that knuckle-crackers were not at higher risk for arthritis. But they were more likely to experience hand-swelling and lower grip strength.

Unger, 83, past president of the American College of Allergy, Asthma and Immunology and the author of more than 40 research papers, says “to become ‘famous’ for this stupidity seems very strange.”

But he sees the humor in it: “Most tombstones are an absolute bore,” he said. “Mine will say, ‘Here lies Don Unger, who finally quit cracking his knuckles.”’