Posterolateral Knee Ligament Reconstruction Using the Arciero Technique Provides Greater Rotational Stability Than the Modified Larson Technique: A Biomechanical Study.

BACKGROUND

It is still unknown if the double-femoral tunnel technique (Arciero [ARC]) provides better stability as compared with the single-femoral tunnel technique (modified Larson [LAR]) in posterolateral corner reconstruction. The ideal angle of fixation of the popliteofibular strand in ARC is also unknown.

HYPOTHESES

The ARC provides greater external rotation (ER) stability than the LAR (hypothesis 1); there is no difference in varus rotation (VR) stability between LAR and ARC (hypothesis 2); and femoral fixation of the popliteofibular strand at 60° during the ARC leads to greater ER stability than fixation at 30° or 90° of knee flexion (hypothesis 3).

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight fresh-frozen human knees were tested in a knee test bench in 4 states: native, posterolateral deficiency, LAR, and ARC. With the ARC, the popliteofibular strand was fixed at 30°, 60°, and 90° (ARC30, ARC60, ARC90). The order of testing (LAR/ARC) was randomized. A tibial ER and VR torque of 5 N·m was applied at 0°, 30°, 60°, and 90°. Rotation degrees were captured using an ultrasound-based analysis system. Wilcoxon signed rank tests were used to assess statistical significance between paired groups in different states.

RESULTS

The ARC and LAR significantly improved VR and ER stability at all flexion angles in comparison with posterolateral deficiency ( < .05). At 60° and 90°, ARC30 showed significantly greater ER stability in comparison with the LAR (mean ± SD; ARC30 vs LAR at 60°, 21.2°± 5.1° vs 15.4°± 5.6° [ < .05]; ARC30 vs LAR at 90°, 23.7°± 5.6° vs 16.8°± 6.3° [ < .05]). At 90°, the LAR showed significantly greater VR instability in comparison with the native state (3.5°± 1.5° vs 2.5°± 1.0°; = .012), and ARC30 was not significantly different from the native state with respect to VR (2.9°± 1.5° vs 2.5°± 1.0°; = .327). No significant differences in ER and VR were found among ARC30, ARC60, and ARC90 at any flexion angle (≥ .05).

CONCLUSION

The ARC technique provided greater tibial ER stability in comparison with the LAR at higher flexion angles (hypothesis 1 accepted). There were no differences between LAR and ARC in restoring VR stability, except at 90° (hypothesis 2 partly accepted). Different femoral flexion angles for fixation of the popliteofibular strand during the ARC did not show any significant differences in relation to knee stability (hypothesis 3 rejected).

CLINICAL RELEVANCE

Posterolateral corner reconstruction using the ARC technique provides greater ER stability at higher flexion angles than the modified LAR technique.