2015 ISAKOS Biennial Congress ePoster #1300

A Randomized Controlled Trial of Different Posterolateral Bundle Graft Fixation Angles in Double-Bundle Anterior Cruciate Ligament Reconstruction

Hideyuki Koga, MD, PhD, Tokyo JAPAN
Takeshi Muneta, MD, PhD, Hinoa-shi, Tokyo JAPAN
Ichiro Sekiya, MD, PhD, Bunkyo-Ku, Tokyo JAPAN

Tokyo Medical and Dental University, Tokyo, JAPAN

FDA Status Not Applicable

Summary: Effect of different posterolateral bundle (PLB) graft fixation angles in double-bundle (DB) ACL reconstruction was evaluated by a randomized controlled trial. When the anteromedial bundle was fixed at 20°, fixation of the PLB at 45° was worse than that of the PLB at 0° and 20° in anterior and rotational stability and graft failure. Therefore, fixation of the PLB at 45° is not recommended.

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Abstract:

Background

In double-bundle (DB) anterior cruciate ligament (ACL) reconstruction, no consensus exists on an optimal setting of graft fixation angles. Previous biomechanical studies have shown that graft fixation angles affect graft tension pattern, as well as anteroposterior and rotational knee laxity; however, there has been no clinical study evaluating the effect of graft fixation angles on clinical outcomes in DB ACL reconstruction.

Hypothesis

Different PLB fixation angles would affect clinical outcomes in DB ACL reconstruction.
Study Design: Randomized Controlled Clinical Trial.

Methods

Ninety patients who underwent primary DB ACL reconstruction with an autologous semitendinosus tendon were prospectively included. PLB fixation angles were randomly set as follows: 1) 0° of flexion (P0; n = 30), 2) 20° (P20; n = 30), and 3) 45° (P45; n = 30). In all groups, the anteromedial bundle was fixed at 20°. The following evaluation methods were used: clinical examination, KT-1000 arthrometer measurement, muscle strength, Tegner score, Lysholm score, subjective rating scale regarding patient's satisfaction and sports performance level, graft retear, contralateral ACL tear, and additional meniscus surgery. Power analysis, with a power of 80% and an alpha of 0.05, demonstrated that a sample size of 24 patients in each group was needed for a 1.0-mm difference with 1.2-mm standard deviation in KT measurements. For statistical analysis, the calculations between the differences of means were made by an analysis of variance (ANOVA), Mann-Whitney U test, and those of the frequencies by the chi-square test. Statistical significance was set for p < 0.05.

Results

Seventy-five patients (P0; n = 25, P20; n = 26, P45; n = 24) who were followed up for 2 years were evaluated. Preoperatively, there were no differences among the groups. Postoperatively, pivot shift test results in the P0 and P20 groups were better than those in the P45 group (p = 0.038 and 0.038, respectively). KT measurements in the P20 group were better than those in the P45 group (average, P0; 0.4 mm, P20; 0.3 mm, P45; 1.3 mm, p = 0.048 in P20 vs. P45), and there were more patients with graft failure (KT measurement > 4 mm) in the P45 group (P0 and P20; no case, P45; 3 cases, p = 0.029). There were no significant differences in range of motion, other laxity tests, muscle strength, Tegner score, Lysholm score, subjective rating scale, and additional surgeries.

Conclusions

In DB ACL reconstruction, when the AMB was fixed at 20°, fixation of the PLB at 45° was worse than that of the PLB at 0° and 20° in anterior and rotational stability during the 2-year follow-up. KT measurements and pivot shift tests were significantly worse and there were the most patients with graft failure in the P45 group; there were no differences in other findings. Therefore, fixation of the PLB at 45° is not recommended, as it might lead to overloading of the PLB, increasing the risk of graft failure.