Table 3.
Torsion stiffness
| 180 mm rings | 155 mm rings | |||||
|---|---|---|---|---|---|---|
| Divergence Angle: | Half pins (1 ring) | Transverse Wires (2 rings) | Transverse Wires (1 ring) | Half pins (1 ring) | Transverse Wires (2 rings) | Transverse Wires (1 ring) |
| 90° | 2.67 (±0.12) | 2.11 (±0.05) | 0.49 (±0.04) | 2.94 (±0.07) | 2.63 (±0.08) | 0.60 (±0.04) |
| 75° | 2.36 (±0.07) | 2.09 (±0.09) | 0.46 (±0.06) | 2.67 (±0.10) | 2.17 (±0.11) | 0.51 (±0.03) |
| 60° | 2.09 (±0.08) | 1.91 (±0.11) | 0.35 (±0.02) | 2.63 (±0.04) | 2.11 (±0.04) | 0.51 (±0.07) |
| 45° | 2.04 (±0.10) | 1.84 (±0.08) | 0.34 (±0.05) | 2.11 (±0.05) | 2.09 (±0.07) | 0.45 (±0.06) |
All values in Nm/deg and brackets show SD. The half pins show significantly more torsion stiffness in both ring diameters (p < 0.05) in comparison to transverse wires. There is increase in stiffness with the increase in the divergence angle as well (p = 0.048). As in axial stiffness, small diameter rings show increased stiffness in torsion. Single ring fixation with transverse wires (without any accessory rings) provides significantly weak construct in both ring diameters and all divergence angles (p = 0.008). For 180 mm rings, the torsion stiffness of half pins construct is between 9.4% to 26.5% more than the transverse wires (with accessory ring) construct. Similarly, for 155 mm diameter rings, there was an increase between 9.5% and 24.6% for half pins in comparison to transverse wires (with accessory ring) construct.