Single- Versus Double-Bundle Anterior Cruciate Ligament Reconstruction Results Using Navigation: The Japanese Experience

Anatomic anterior cruciate ligament (ACL) reconstructions that more closely approximate the anatomy of the ACL have gained in popularity, especially in Japan. Meanwhile, computer-assisted surgical navigation devices have been adopted in ACL reconstruction for improved accuracy of tunnel placement. Navigation systems also can be used to assess knee kinematics before and after ACL reconstruction during surgery. In this article, we introduce intraoperative biomechanical evaluation of double-bundle reconstruction with a hamstring graft and anatomically oriented single-bundle reconstruction with a patellar tendon graft with the use of a navigation system. Results showed that both reconstructions similarly improved knee laxity compared with before reconstruction in all knee flexion angles. Regarding the function of the bundles in double-bundle reconstruction, the posterolateral bundle restrained tibial displacement mainly in knee extension, whereas the antero-medial bundle restrained it more in the knee flexion position. These results showed that both bundles in anatomic double-bundle reconstruction could share the resultant force under anterior tibial load similar to that of bundles in the intact ACL. Therefore, both bundles should be reconstructed to improve knee laxity throughout knee range of motion. Even with single-bundle reconstruction with the use of a patellar tendon, anatomical reconstruction might improve knee laxity similar to double-bundle reconstruction. We have also included evaluation of tunnel placement in anatomic double-bundle reconstruction using a navigation system and compared these evaluations with anatomical data.