Reconstruction du ligament croisé antérieur par greffe de tendons de la patte d’oie à un ou à deux faisceaux: Comparaison biomécanique sur genoux cadavériques

Abstract

Purpose of the study We worked with cadaver specimens to evaluate control of anterior knee laxity after reconstruction of the anterior cruciate ligament (ACL) comparing double two-strand anterolateral and posteromedial reconstruction with the classical four-strand technique. We hypothesized that the double reconstruction would provide better control of anterior laxity in both flexion and extension. Material and methods Sixteen cadaver knees were randomly assigned to reconstruction technique. Anterior tibial translation was measured with an arthrometer (Rolimeter™) at maximal manual tension at 20°, 60° and 90° flexion on the intact knee, after section of the ACL and after arthroscopic reconstruction using either the classical four-strand hamstring technique or a double two-strand anteromedial and posterolateral technique. An EndoButtonCL™ was used for the femoral fixation and a interference screw with staples for the tibial fixation. Variation in the length of each construct was measured between 0° and 90° flexion. Results In the single reconstruction group, the length of the graft varied by 0.5 ± 0.7 mm between 0° and 90° flexion. In the double reconstruction group, the length varied by 0.5 ± 0.9 mm for the anteromedial construct and 3.4 ± 0.5 mm for the posterolateral construct. When studied with an intact ACL, anterior laxity of the 16 knees was 3.2 ± 1.1, 3.5 ± 1.5 and 2.6 ± 1.1 mm at 20°, 60°, and 90° respectively. After section of the ACL, laxity increased significantly at all angles: 9.4 ± 3.3, 6.1 ± 2.5 and 6.8 ± 2.9 at 20°, 60°, and 90° respectively. After classical four-strand single graft reconstruction, the residual anterior laxity was 3.7 ± 0.9, 3.1 ± 1.1, and 2.3 ± 1.6 mm at 20°, 60°, and 90° flexion. Statistical analysis using parametric or non-parametric tests as appropriate showed a significant difference in laxity at 20°, 60°, and 90° of flexion between knees with a cut ACL and knees with reconstructed ACL. At 20° flexion, residual laxity was greater after single-construct reconstruction. At 60° and 90° there was no significant difference in anterior translation of the tibia in knees with intact or reconstructed ACL. After reconstruction with the dual-construct technique, laxity was 3.4 ± 1.3, 2.6 ± 1.5, and 2.4 ± 1.2 mm at 20°, 60° and 90° flexion respectively. Laxity was significantly greater with a cut ACL than after reconstruction at 20°, 60°, and 90° flexion, but there was no significant difference in anterior translation of the tibia at 20°, 60°, and 90° flexion between knees with an intact and a reconstructed ACL. Discussion These results based on a clinical evaluation measuring anterior translation of the tibia with an arthrometer are in agreement with results in the literature using robots. Compared with the classical technique, reconstruction of the ACL with a dualconstruct technique provides a statistically significant improvement in control of anterior tibial translation at 20° of flexion. The advantage of the dual anteromedial and posteriolateral construct technique is thus not found in the control of anterior laxity but rather in control of rotation laxity. Conclusion Reconstruction of the ACL with a two-bundle graft technique provides control of anterior laxity at 20°, 60°, and 90° flexion similar to that observed in knees with an intact ACL while the single construct technique re-establishes physiological laxity at 60° and 90° only. This improved control of anterior laxity with the two-bundle reconstruction is a small improvement regarding anterior laxity, the more potential advantage concerning rotational stability.