Outcome of intra-articular lumbar facet joint corticosteroid injection according to the severity of facet joint arthritis.

Lumbar facet joint osteoarthritis (FJOA) caused by degenerative change(s) is considered to be the main cause of facet joint-origin low back pain (LBP). Intra-articular lumbar facet joint (IA LFJ) corticosteroid injection is widely used for controlling pain induced by FJOA. In the current study, the outcomes of IA LFJ corticosteroid injection were evaluated according to the severity of FJOA. A total of 50 patients who received IA LFJ corticosteroid injections for the treatment of LFJ pain were recruited. Patients were classified into three groups according to the severity of FJOA, which was indicated during a lumbar axial MRI. A total of 10 patients were assigned to group A (patients with mild FJOA), 27 to group B (patients with moderate FJOA) and 13 to group C (patients with severe FJOA). Pain intensity was evaluated using a numerical rating scale (NRS) prior to treatment and at 1, 2 and 3 months after treatment. A total of 26 (52%) patients experienced successful treatment outcomes (defined as >50% reduction in NRS score at 3 months). Patients in all groups demonstrated a significant decrease in NRS scores at 1, 2 and 3 months after IA LFJ corticosteroid injection compared with the pre-treatment score (P<0.001). However, the effect of IA LFJ corticosteroid injection was not significantly different among the three groups (P=0.889). The results demonstrated that facet joint-origin LBP was significantly reduced after IA LFJ corticosteroid injection, regardless of the severity of FJOA. The results of the current study indicated that IA LFJ corticosteroid injection is a beneficial clinical option for managing LBP caused by FJOA.