Osteoarthritis
This form of arthritis is common in persons from 50 years of age. It can also occur in younger people. What happens is that the cartilage that keeps the bones from rubbing against each other wears away
Rheumatoid Arthritis
This happens when your immune system attacks your joints. The synovial membrane covering the joint becomes inflamed. This can damage the cartilage and lead to stiffness and pain