Table.

Neutral zone (degrees) calculated during non-destructive pure moment loading

Neutral zone (degrees)
Treatment	Time point	Axial rotation	Flexion- extension	Lateral bending
PEEK	8 wk	0.15 ± 0.05A,D,G	0.67 ± 0.14J	0.62 ± 0.14
PSP	8 wk	0.19 ± 0.06B,E	1.08 ± 0.14H,I,K,L	0.79 ± 0.10M,N
PTA	8 wk	0.17 ± 0.05C,F	0.58 ± 0.14H	0.41 ± 0.15
PEEK	16 wk	0.00 ± 0.00A,B,C	0.37 ± 0.12I	0.19 ± 0.11M
PSP	16 wk	0.04 ± 0.04G	0.40 ± 0.19I	0.28 ± 0.13
PTA	16 wk	0.00 ± 0.00D,E,F	0.05 ± 0.05J,K	0.14 ± 0.07N

PEEK, polyetheretherketone; PSP, plasma sprayed porous titanium-coated PEEK; PTA, porous titanium alloy.

Data means are shown with standard deviations; values with similar roman letters indicate statistically significant differences. Significant p-values are given below:

Axial rotation—

^A:p<.01;

^B:p=.03;

^C:p=.01;

^D:p<.01;

^E:p=.03;

^F:p=.01;

^G:p=.05.

Flexion-extension—

^H:p=.04;

^I:p<.01;

^J:p=.03;

^K:p<.01;

^L:p=.01.

Lateral bending—

^M:p=.02;

^N:p<.01.