Arthritis affects almost 300,000 people under age 18. Juvenile arthritis is one of the most common childhood diseases in the U.S. While it's often caused by genetics, children are not the only ones affected by arthritis. Each year arthritis-related illnesses affect people of all ages, costing the U.S. a staggering $128 billion.

Dr. Gregory Auzenne at Rush Hospital says there's a good reason for this.

"Arthritis is a general catch-all term for over 100 different disease entities, but probably the top three that we are mostly concerned with are osteoarthritis, which affects about 27,000,000 people in the United States," said Auzenne. "And 1.3 million are affected by rheumatoid arthritis."

Dr. Auzenne says both conditions cause pain in joints that can hinder everyday activities. He says osteoarthritis is often caused by general wear and tear on the body and affects large joints. However, he said rheumatoid arthritis, is more often caused by genetics.

"Many times there are medications that they can prescribe to delay the onset of the symptoms of the disease itself. Osteoarthritis sometimes can be treated by just exercise and mild medications. So, they are very different types, but to the patients, they are still very painful and debilitating," Auzenne said.

If you hear cracking in your knees when you bend down, Auzenne said it's not cause for alarm, as long as you don't experience pain. But if pain ever starts, Auzenne says you should see a doctor.

With no real cure for arthritis, Dr. Auzenne says one type of treatment is aquatic therapy, often more gentle on joints. Joint replacements would be a final option. Auzenne says be it medication or therapeutic movements, often early intervention now can help the patient later.

"So, the earlier on you can get treatments from your physician the more likely you are to prevent those end stage situations," Auzenne said.