Table 2 Grading of facet joint osteoarthritis (FJO)
Degeneration degree | Standard |
|---|---|
I (normal) | Normal facet joint (joint gap is 2–4 mm) |
II (mild) | Narrow space (< 2 mm) and/or mild osteophytes and/or mild hypertrophy of facet joints |
III (moderate) | Narrow space (< 2 mm) and/or moderate osteophytes and/or moderate hypertrophy of facet joints and/or mild erosion of subarticular cartilage |
IV (severe) | Narrow space (< 2 mm) and/or large osteophytes and/or severe hypertrophy of facet joints and/or severe erosion of subarticular cartilage and/or subchondral cysts |