Although they sound almost the same, osteoporosis and osteoarthritis are two very different conditions.
Osteoporosis is a progressive bone disease. If you have osteoporosis, your bones become weak and brittle, causing you to be at greater risk for bone fractures.
Osteoarthritis is the most common type of arthritis, which is inflammation and deterioration of your joints. Osteoarthritis is the result of every day wear and tear, and is most common in older adults.