Table 2.

Force, Moment, and Displacement Data for the Combined-Loading Specimens

	Unit of measure	Mean ± SD	Minimum	Maximum
Compressive force and anterior flexion moment
Compressive axial force at peak of loading	kN	1.22 ± 0.56	0.22	2.32
Moment at peak of loading	Nm	6.77 ± 7.13	0.50	28.81
Drop in force immediately after peak of loading	kN	0.11 ± 0.17	−0.03	0.58
	%	11.0 ± 17.4	−3.0	58.3
Drop in force at the onset of grade 1 fracture (n = 11a)	kN	0.04 ± 0.26	−0.43	0.34
	%	12.2 ± 34.3	−34.1	89.3
Drop in moment immediately after peak of loading	Nm	1.78 ± 0.71	0.39	2.75
	%	47.1 ± 33.4	5.2	255.0
Drop in moment at the onset of grade 1 fracture (n = 11a)	Nm	3.42 ± 1.62	1.86	7.48
	%	71.5 ± 33.3	30.5	122.7
Endplate deflection
Maximum deflection at peak of loading	mm	0.38 ± 0.25	0.19	1.00
	%	1.9 ± 1.3	0.9	5.5
Maximum deflection immediately after peak of loading	mm	1.36 ± 0.66	0.37	2.78
	%	6.9 ± 3.5	1.8	15.2
Increase in deflection	mm	0.98 ± 0.50	0.15	1.78
	%	5.0 ± 2.6	0.7	9.8
Anterior displacement
Maximum anterior displacement at peak of loading	mm	0.063 ± 0.062	0.001	0.204
	%	15.8 ± 12.7	0.5	47.3
Maximum anterior displacement immediately after peak of loading	mm	0.256 ± 0.131	0.075	0.565
	%	19.9 ± 7.2	10.3	33.2
Increase in anterior displacement	mm	0.192 ± 0.134	0.045	0.548
	%	22.9 ± 12.9	4.6	40.0

Values presented are mean ± standard deviation (SD), minimum, and maximum (n = 14 except where noted). Compressive force and flexion moment at the peak of loading, and the drop in force (in kN and as a percentage of the ultimate force) and moment (in Nm and as a percentage of the ultimate moment) immediately after the peak of loading. Maximum endplate deflection measured at and immediately after the peak of loading, and the increase in deflection between these two load increments (in mm and as a percentage of the height of the vertebral body). Maximum outward displacement in the anterior cortex measured at and immediately after the peak of loading, and the increase between these two load increments (in mm and as a percentage of the maximum endplate deflection for the same specimen at the same increment).

^aThree specimens remained at grade 0.