Intraoperative biomechanical evaluation of anatomic anterior cruciate ligament reconstruction using a navigation system: comparison of hamstring tendon and bone-patellar tendon-bone graft.
BACKGROUND
Recently, more anatomic anterior cruciate ligament reconstructions have been developed to improve knee laxity.


OBJECTIVE
The objective of this study is to assess knee kinematics after double-bundle reconstruction with hamstring tendon and after anatomically oriented reconstruction with a patellar tendon using navigation during surgery.


METHODS
Cross-sectional study; Level of evidence, 3.


METHODS
Eighty knees received double-bundle reconstruction with a hamstring tendon graft, and 45 knees received anatomically oriented reconstruction with a patellar tendon graft. Before reconstruction, knee laxity was measured using a navigation system. After the posterolateral bundle or anteromedial bundle was temporarily fixed during double-bundle reconstruction, knee laxity was measured to assess the function of each bundle. After double-bundle reconstruction or anatomically oriented reconstruction with patellar tendon, knee laxity was measured in the same manner.


RESULTS
Both double-bundle reconstruction and anatomically oriented reconstruction similarly improved knee laxity compared with before reconstruction in all knee flexion angles. Regarding the function of the anteromedial and posterolateral bundles in double-bundle reconstruction, the 2 grafts showed contrasting behavior. The posterolateral bundle restrained tibial displacement mainly in knee extension, whereas the anteromedial bundle restrained it more in the knee flexion position. The posterolateral bundle has a more important role in controlling rotation of the tibia than the anteromedial bundle.


CONCLUSIONS
Although the posterolateral bundle has an important role in the extension position, the anteromedial bundle is more important in the flexion position. Therefore, both bundles should be reconstructed to improve knee laxity throughout knee range of motion. Even with single-bundle reconstruction using a patellar tendon, anatomic reconstruction might improve knee laxity similar to double-bundle reconstruction.
Ishibashi
Yasuyuki
Y
Department of Orthopaedic Surgery, Hirosake University School of Medicine, Aomori, Japan. yasuyuki@cc.hirosaki-u.ac.jp
Tsuda
Eiichi
E
Fukuda
Akira
A
Tsukada
Harehiko
H
Toh
Satoshi
S