Weishaupt et al. refined grading of Pathria et al. to grade facet joint osteoarthritis on CT and MRI
Grading
Grade 0
normal facet joint space (2-4 mm width)
Grade 1
narrowing of joint space (<2 mm) and/or small osteophytes and/or mild hypertrophy of articular processes
Grade 2
narrowing of joint space and/or moderate osteophytes and/or moderate hypertrophy of articular processes and/or mild subarticular bone erosions
Grade 3
narrowing of facet joint space and/or large osteophytes and/or severe hypertrophy of articular process and/or severe subarticular bone erosions and/or subchondral cysts