Lumbar facet joint orientation and osteoarthritis: A cross-sectional study

BACKGROUND AND OBJECTIVE: The association between facet orientation, tropism (asymmetry of the facet angles) and facet joint osteoarthritis (OA) has been previously reported, however, it is necessary to confirm the association in other samples. Our aim was to evaluate the association between facet orientation, tropism, and facet joint OA in an Israeli sample. METHODS: One hundred and fifty low back and abdominal CTs of 82 males (mean age 61.74 +/- 12.99) and 68 females (mean age 59.51 +/- 11.74,) were evaluated in a cross-sectional study. Facet joint OA was evaluated at the L4-L5 spinal level using a 4-graded scale. The association between facet joint OA, facet orientation and tropism was examined using multiple logistic regressions adjusted for age and sex. RESULTS: Facet orientation showed a statistically significant association with facet joint OA on the right side (p = 0.009) and in a model where both sides were combined (p = 0.003). Facet joints with OA were more sagittally oriented. Tropism was not associated with facet joint OA on either side (p = 0.251 for right and 0.609 for the left side), or in a combination of both sides (p = 0.482). CONCLUSIONS: We confirm a significant association between sagittal orientation and OA of the lumbar facet joints at level L4-L5. Facet tropism was not associated with facet joint OA. Additional longitudinal studies are needed to understand the causal relationship between facet joint orientation and OA.