1998: Does habitually cracking your knuckles lead long-term to arthritis, or is that an old wives’ tale? Ignoring warnings from a number of old wives – “his mother, several aunts, and, later, his mother-in-law” – Donald Unger conducted an experiment, cracking the knuckles of his left hand, but not his right, at least twice a day.
After keeping up his daily routine for half a century, Unger checked both hands and found no evidence of arthritis. “There is no apparent relationship,” he concluded, “between knuckle cracking and the subsequent development of arthritis of the fingers.”
Source: Arthritis & Rheumatism, May 1998