Osteoporosis versus Osteoarthritis

Are osteoporosis and osteoarthritis the same?

This is a question we often get asked and one over which there seems to be some confusion. While both terms include the term ‘osteo’, which means bone, the similarity ends there. They are both quite different conditions.

Osteoporosis involves thinning of the bone which makes it fragile, brittle and more prone to fracture (breaks or cracks) than normal bone. It occurs when bone loses minerals, such as calcium, faster than the body can replace them. This leads to a loss of bone density. As a result bone becomes thinner and less dense so that even a minor bump or accident can cause a fracture. Such fractures are known as minimal trauma or fragility fractures.

Osteoporosis is known as a ‘silent disease’ because there are usually no signs or symptoms until a fracture occurs. The bones most commonly affected by osteoporosis are the hip, spine, wrist, pelvis and upper arm.

Osteoarthritis, on the other hand, does not affect bone density. Osteoarthritis is a condition that affects the joints. In a normal joint the ends of the bone a covered by cartilage. This cartilage helps the bone move smoothly and cushions the ends of the bones. In osteoarthritis the cartilage breaks down and becomes thin. When this occurs the ends of the bone are unprotected and the joint loses its ability to move smoothly.


  1. Osteoporosis Australia website – accessed July 2011
  2. Arthritis Australia fact sheet ‘What is osteoarthritis?’, reviewed 2011