Facet joint surfaces are covered with a layer of cartilage that facilitates smooth and easy movement between the vertebrae. This cartilage layer can be damaged or worn down due to various factors. Causes such as aging, wear and tear from overuse, physical trauma, rheumatic diseases, and previous surgical interventions can lead to cartilage degeneration in the facet joints. As facet joints degenerate—that is, as they wear down—their function deteriorates. When the joint surfaces wear away, bones can start rubbing against each other, potentially causing pain.