If you are over 40 years old and you’ve had X-rays of your spine, you might be convinced that any back pain you have is coming from those joints. That’s because as we age, signs of degeneration are abundant. Bone spurs grow around the joints, the joint cartilage thickens and reduces movement, and overgrowth of the joint margins blocks motion.
But the truth is, there are just as many people with degenerative changes seen on X-ray who don’t have any back pain. How is that possible? Scientists don’t really know. But they’ve been studying the relationship between low back pain and facet (spinal) joint degeneration for years.
There’s some evidence that lumbar facets could cause low back pain. The anatomical structures in that area have a lot of nerves that could get irritated and send painful messages up the spinal cord to the brain. Arthritic changes are most common in the lumbar spine, especially at the L4-L5 level.
But most studies don’t show a statistically significant relationship between facet osteoarthritis and low back pain. And it’s not because those changes aren’t present. They are — a recent study of a large number of people (over 3,500) found an increasing incidence of facet joint changes as people got older.
About one-quarter of the group who were 40 years old or younger had facet joint changes. This compared with two-thirds of the group 70 years old and older. But there were no degenerative or arthritic changes that predicted low back pain. And that is a major finding to support the idea that degenerative changes and arthritis of the facet joints are not responsible for low back pain.
Physicians looking at X-rays don’t assume that even the worst of degenerative changes seen on imaging studies have any clinical meaning. That patient’s back pain may not be coming from the facet joint(s) despite appearances otherwise.