Most knuckle crackers will have been told — probably in an effort to get them to stop doing it — that they risk arthritis if they continue. The scientific community, though, says there is no hard proof to back that up.
’We have no evidence that cracking your knuckles causes arthritis in the long term: there simply haven’t been good studies to make a decision about this,’ says Professor Philip Conaghan of the academic unit of musculoskeletal medicine at the University of Leeds.
Professor Conaghan, a spokesman for Arthritis Research UK, adds: ‘However, knuckle cracking may be associated with tendon and other soft tissue problems.’
Knuckles are lubricated by synovial fluid, a yolk-like substance that reduces friction between the bones, easing movement. Cracking happens when the joints are stretched to the point that bubbles of dissolved gases are formed, which then pop. Once a knuckle is cracked, it takes about 15 minutes for the gases to reform.
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