Table 1.
Sacroiliac joint range of motion for an intact model and 22 configurations of implant orientation, superior implant length, and number of implants
| Treatment/orientation |
Implant placed |
Superior implant ending point |
SI joint ROM (°) [Reduction in ROM (%)] |
||||
| Superior | Middle | Inferior | Flexion-extension | Lateral bending | Axial rotation | ||
| Intact | - | - | - | -1 | 1.94° (-) | 0.66° (-) | 1.11° (-) |
| Inline orientation | X | X | X | Mid-ala | 0.7° (64%) | 0.45° (32%) | 0.41° (63%) |
| Mid-sacrum | 0.63° (68%) | 0.41° (38%) | 0.38° (66%) | ||||
| X | - | X | Mid-ala | 0.82° (58%) | 0.47° (29%) | 0.44° (60%) | |
| Mid-sacrum | 0.69° (64%) | 0.43° (35%) | 0.4° (64%) | ||||
| X | X | - | Mid-ala | 0.97° (50%) | 0.5° (24%) | 0.49° (56%) | |
| Mid-sacrum | 0.76° (61%) | 0.45° (32%) | 0.43° (61%) | ||||
| - | X | X | -1 | 0.91° (53%) | 0.53° (20%) | 0.55° (50%) | |
| X | - | - | Mid-ala | 1.36° (30%) | 0.58° (12%) | 0.67° (40%) | |
| Mid-sacrum | 1.21° (38%) | 0.58° (12%) | 0.61° (45%) | ||||
| - | X | - | -1 | 1.32° (32%) | 0.65° (2%) | 0.73° (34%) | |
| - | - | X | -1 | 1.25° (36%) | 0.69° (-5%) | 0.79° (29%) | |
| Transarticular orientation | X | X | X | Mid-ala | 0.59° (70%) | 0.41° (38%) | 0.34° (69%) |
| Mid-sacrum | 0.52° (73%) | 0.38° (42%) | 0.31° (72%) | ||||
| X | - | X | Mid-ala | 0.69° (64%) | 0.42° (36%) | 0.36° (68%) | |
| Mid-sacrum | 0.58° (70%) | 0.39° (41%) | 0.32° (71%) | ||||
| X | X | - | Mid-ala | 0.81° (58%) | 0.45° (32%) | 0.4° (64%) | |
| Mid-sacrum | 0.64° (67%) | 0.41° (38%) | 0.35° (68%) | ||||
| - | X | X | -1 | 0.76° (61%) | 0.47° (29%) | 0.46° (59%) | |
| X | - | - | Mid-ala | 1.36° (30%) | 0.58° (12%) | 0.67° (40%) | |
| Mid-sacrum | 1.21° (38%) | 0.58° (12%) | 0.61° (45%) | ||||
| - | X | - | -1 | 1.11° (43%) | 0.6° (9%) | 0.7° (37%) | |
| - | - | X | -1 | 1.05° (46%) | 0.62° (6%) | 0.73° (34%) | |
1
Configuration does not include a superior implant. SI: Sacroiliac; ROM: Range of motion.