Sacroiliac joint stability: Finite element analysis of implant number, orientation, and superior implant length

Table 3 Reduction in sacroiliac joint range of motion (°) between mid-sacrum and mid-ala placement groups

			Reduction in SI joint ROM (°) (%)
Superior implant ending point	Orientation	Implants (position)	Flexion-extension	Lateral bending	Axial rotation
Mid-sacrum vs mid-ala	Inline	3 (S, M, I)	0.07° (10%)	0.04° (9%)	0.03° (7%)
		2 (S, -, I)	0.13° (16%)	0.04° (9%)	0.04° (9%)
		2 (S, M, -)	0.21° (22%)	0.05° (10%)	0.06° (12%)
		1 (S, -, -)	0.15° (11%)	0.00° (0%)	0.06° (9%)
	Trans-articular	3 (S, M, I)	0.07° (12%)	0.03° (7%)	0.03° (9%)
		2 (S, -, I)	0.11° (16%)	0.03° (7%)	0.04° (11%)
		2 (S, M, -)	0.17° (21%)	0.04° (9%)	0.05° (13%)
		1 (S, -, -)	0.15° (11%)	0.00° (0%)	0.06° (9%)
	Median (°) (Range)		0.14° (0.07-0.21)	0.035° (0.00-0.05)	0.045° (0.03-0.06)
	Median (%) (Range)		14% (10-22)	8% (0-10)	9% (7-13)

The reduction in range of motion (%) was calculated in comparison to the to the mid-ala superior implant length. S: Superior; M: Middle; I: Inferior.