Medication advances. Most common is osteoarthritis, which responds to heat, mobility, and non steroidal anti-inflammatory medications. Treatment may help symptoms but not necessarily the eventual course. Arthritis from rheumatoid arthritis, lupus, and psoriasis can dramatically respond to newer disease-modifying antirheumatic drugs which are substances that modify the body's response to infection and disease.
JAK inhibitors. Let's assume we are talking about rheumatoid arthritis. The most recent fda-approved medication is tofacitinib, which inhibits proteins called jaks that help cells know if there is inflammation (via cytokines) is around them.