Figure 5.

Computed tomography Criteria for grading facet joint arthropathy (a) Normal facet joints (joint space 2–4 mm) (b) joint space narrowing (joint space <2 mm) and/or small osteophytes and/or mild hypertrophy of the articular processes (c) joint space narrowing and/or moderate osteophytes and/or moderate hypertrophy of the articular processes and/or mild subarticular bone erosions (d). Joint space narrowing and/or large osteophytes and/or severe hypertrophy of the articular processes and/or severe subarticular bone erosions and/or subchondral cysts