Blame this kind of joint pain on cartilage—or a lack thereof. As the connective tissue wears away, the subsequent bone-on-bone contact can trigger pain ranging from mild to severe. It's more common among obese people (as excess weight increases pressure on joints) and the elderly (because cartilage deteriorates with age), but it can also develop from an injury like a torn meniscus or ACL. Cortisone injections are one option, but overdoing the shots may worsen joint damage, which is why many doctors limit the number of injections patients can receive in a year.
Alternative Rx: Acupuncture
This needling technique has been used to treat pain for centuries, and evidence suggests it can be particularly effective in treating knee osteoarthritis. A 2012 study found that acupuncture could be a low-cost substitute for knee surgery, providing substantial pain relief in about a third of patients. Researchers believe the needles may trigger nerves to signal the brain to release endorphins that naturally dull pain.