What is Facet Arthritis?
Facet Arthritis (or Facet Arthropathy) is arthritis of the facet joint. The facet joints break down from aging, wear and tear, injury, instability, and slipping of the spine called spondylolithesis. This wearing out of the facet joints is called degeneration. These degenerative changes may produce pain.
The most common cause of facet arthritis is osteoarthritis. “Osteo” means bone and arthritis means inflammation of joints. Osteoarthritis causes the breakdown and swelling in the cartilage of the facet joint ultimately producing bone on bone rubbing. The body tries to stop this rubbing by thickening the joint. Arthritis of the facet joints may produce pain and stiffness. If the joints enlarge too much, they may pinch nerves causing arm or leg pain.
Facet arthropathy may be diagnosed on x-rays, CT and MRI. CT scan may show thickened irregular facet joints. MRI scan may show joint swelling, thickened ligaments and bones and pinched nerves. These imaging studies only show the physical abnormality. They do not indicate if these changes are responsible for your pain.
To determine the painful structure the patient may undergo pain mapping. Facet injections are used to localize where the pain is coming from. Numbing medicine is injected into the facet joint or onto the facet nerve (medial branch nerve). If the pain is caused by the facet joint the pain will stop or decrease. If the pain does not improve then the pain is not from the facet joint, but is originating from something else, such as the bones, disks, ligaments, spinal nerves, etc.