INTRODUCTION: Several reports have described that a significant number of patients with rheumatoid arthritis (RA) have deformity of the lumbar spine, and the incidence is more frequent than that in patients without RA. Some reports have described that inflammation of the disco‐vertebral junction is one of the typical features of these patients. However, only a few studies have assessed this feature by MRI. The aims of this study were to assess endplate erosion in the lumbar spine of RA patients by MRI and to evaluate the factors related to endplate erosion.
METHODS: A total of 49 patients who fulfilled the revised criteria of the American Rheumatism Association were included in this study. The background of RA was assessed based on the following points: age, duration of disease, DAS‐28 CRP, and RA stage and class by Steinblocker's criteria. The endplate erosion was evaluated by MRI using a new grading system with four grades. We also examined the prevalences of lumbar scoliosis, spondylolisthesis and vertebral fracture on plain X‐rays. We analyzed the correlations between the degree of endplate erosion and the background factors or radiographic lumbar lesions.
RESULTS: Endplate erosion was observed in 38 patients (77.6%). The background factors of RA did not affect the endplate erosion. The prevalences of lumbar scoliosis, spondylolisthesis and vertebral fracture were 32.7%, 36.7% and 22.4% respectively. The degree of endplate erosion was severe in patients with lumbar scoliosis. In contrast, there were no correlations between the degree of endplate erosion and the presence of spondylolisthesis or vertebral fracture.
DISCUSSION: In the present study, the prevalences of endplate erosion and lumbar deformity were relatively high in patients with RA. There was a correlation between the prevalence of lumbar scoliosis and the degree of endplate erosion.