Repetitive strain injury
Any joint that is repeatedly overused will gradually become weakened. Pain in the joint is caused by a blockage that impedes the flow of blood and energy.
In Chinese medicine this can also be linked to external climatic factors. Wind, cold and damp, can invade the joint, making the problem worse.
Treatment would involve needling points locally opening up the affected acupuncture channels to increase the flow of blood and energy.
Most cases respond very well to acupuncture.