Classification of the grades and severity of proximal junctional kyphosis and PJF.10
| Classification | Description |
| Type | |
| 1 | Disc and ligamentous failure |
| 2 | Bone failure |
| 3 | Implant/bone interface failure |
| Grade | |
| A | Proximal junctional increase 10°–19° |
| B | Proximal junctional increase 20°–29° |
| C | Proximal junctional increase 30° |
| Spondylolisthesis | |
| PJF-N | No obvious spondylolisthesis above UIV |
| PJF-S | Spondylolisthesis above UIV |
Abbreviations: PJF, proximal junctional failure; UIV, uppermost instrumented vertebra.