Two suggested indices of paraspinal muscle degeneration showed excellent reliability and were significantly associated with facet joint osteoarthritis. Additional studies are needed to evaluate the associations with other spinal degeneration features and low back pain.

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.