Comparison of the UIV tilt angle and UIV screw angle in patients with and without proximal junctional kyphosis.
| Variables | With PJK | Without PJK | P |
| UIV tilt angle | |||
| Mean ± SD | 13.6° ± 14.1° | 12.5° ± 13.4° | 0.689 |
| Lordotic UIV tilt angle, n (%) | 34 (36.9) | 58 (63.1) | 0.405 |
| Neutral/kyphotic UIV tilt angle, n (%) | 7 (28.0) | 18 (72.0) | |
| UIV screw angle | |||
| Mean ± SD | –0.4° ± 7.9° | –4.7° ± 7.7° | 0.005 |
| Cranially directed screws, n (%) (N = 32) | 17 (53.1) | 15 (46.9) | 0.012 |
| Neutral/caudally directed screws, n (%) (N = 85) | 24 (28.2) | 61 (71.8) |
Abbreviation: UIV, upper instrumented vertebrae.