It's "Pulsed Electromagnetic Field (Therapy)". I think the name tells what it's all about. It's usually used for treating bones/cartilage. It's controversal, unproven and some put it in the field of homeopathy. (Yet I know another controversal, unproven treatment which is very promising
). PEMF has no risks/side effects.
"There is only one good, knowledge, and one evil, ignorance." Socrates