Osteoarthritis is the most common form of arthritis, and happens when the cartilage protecting joints gets worn down. It's painful and debilitating, but new research suggests that low-dose radiation therapy (LDRT) may work as a countermeasure. Researchers from across South Korea ran a clinical trial involving 114 people with knee osteoarthritis to compare two different doses of LDRT and a sham treatment, which had no actual radiation. Participants were not aware of which group they were in.