When it comes to osteoarthritis, scientists are still scratching their heads about what kicks it all off. But once it gets going, it’s like a wrecking ball inside your joint, messing up everything from the cartilage to the bone. And as things go downhill, you start feeling pain, swelling, and stiffness. That discomfort can make you less active, which weakens your muscles and puts even more strain on the joint. Over time, the joint shape starts to warp, with little bone growths popping up and bits of bone or cartilage floating around causing more trouble.