【Introduction】

There are few detailed reports of facet joint osteoarthritis (FJOA) in epidemiological studies. The aim of this study was to evaluate the characteristics of individuals with FJOA and their association with low back pain (LBP) and LBP-related QOL using epidemiological data. 

【Methods】

The subjects were 437 community residents (142 males and 295 females, mean age 65.0 years) who underwent lumbar spine MRI. FJOA from L1-L to L5-S using the Weishaupt classification (4 grades from 0-3) was evaluated and grade ≥2 was defined as FJOA. Furthermore, subjects underwent blood and urine sampling, blood pressure measurement to assess for hypertension, diabetes, hepatic and renal dysfunction. Arteriosclerosis was assessed by cardio-ankle vascular index (CAVI) and osteoarthritis (OA) of the hip and knee joints were evaluated by the ARA classification (Altman 1986, 1991). LBP was assessed with a self-administered questionnaire and defined as pain requiring treatment lasting at least 1 month. The Roland-Morris Disability Questionnaire (RDQ) was assessed with a norm-based score, and subjects with score less than 50 were considered to have low LBP-related QOL compared to national norm. We compared age, gender, BMI, prevalence of comorbidities, LBP, and RDQ<50 between the FJOA (+) and (-) groups. Chi-square test, Mann-Whitney U test, and multiple logistic regression analysis were used for statistical examination, and a p-value < 5% was considered statistically significant.

【Results】

A total of 225 subjects were enrolled, excluding those with compression fractures, scoliosis or degenerative spondylolisthesis. There were 179 (79.1%) subjects in the FJOA (+) group and 46 (20.9%) in the FJOA (-) group. Only age (66.6 ± 9.6 vs. 59.3 ± 14.7, p = 0.005) was significantly different between the two groups. On the other hand, there were no significant differences in gender, BMI, or prevalence of any comorbidity: gender (male/female 0.62 vs 0.35 p=0.12), BMI (23.3 ± 3.1 vs 23.4 ± 3.5, p=0.84) hypertension (53.6% vs 56.5%, p=0.73), diabetes (5.6% vs 0.0%, p=0.10), hepatic (34.6% vs 34.8%, p=0.741) and renal dysfunction (38.5% vs 41.3%, p=0.99), arteriosclerosis (33.6% vs 23.1%, p=0.21), and osteoarthritis of the knee (33.5% vs 26.7%, p=0.38) and hip (5.6% vs 8.7%, p=0.442). Finally, multiple logistic regression analysis adjusted for age, gender, and BMI showed no significant differences between FJOA and LBP (OR= 1.09, 95%CI: 0.37-3.15, p=0.88), RDQ<50 (OR=0.51, 95%CI: 0.24-1.12, p=0.09). 

【Discussion】

In the present study, there was no association between FJOA and comorbidities, suggesting that FJOA may be an aging process or secondary to mechanical stress. Additionally, we found no association between FJOA and LBP or LBP-related QOL. Further evaluation of other spinal degenerative findings including intervertebral discs and longitudinal studies are needed to validate these results.