X-rays aren’t really useful in diagnosing osteoarthritis, since a significant amount of cartilage must be lost before the damage shows up on an X-ray. But X-rays in someone known to have osteoarthritis can reveal the extent of the damage. They can show how much cartilage has been lost, whether underlying bone has been damaged, or whether bone spurs are present. In addition, X-rays taken periodically can monitor the progression of osteoarthritis.
Interestingly, the severity of a person’s symptoms may be totally unrelated to how the joint looks on an X-ray. In fact, only one third of people whose X-rays show the presence of osteoarthritis report pain or any other symptoms. On the other hand, some people whose joints look perfectly normal on an X-ray may have excruciating symptoms from osteoarthritis.
Another imaging technique — magnetic resonance imaging, or MRI — excels at revealing injuries to soft tissues such as muscles and tendons. But so far, MRI has no advantage over X-rays in evaluating or monitoring joints affected by osteoarthritis.