Abstract
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 (P < .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° [P < .05]; ARC30 vs LAR at 90°, 23.7°± 5.6° vs 16.8°± 6.3° [P < .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°; P = .012), and ARC30 was not significantly different from the native state with respect to VR (2.9°± 1.5° vs 2.5°± 1.0°; P = .327). No significant differences in ER and VR were found among ARC30, ARC60, and ARC90 at any flexion angle (P≥ .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.