Navigation evaluation of the pivot-shift phenomenon during double-bundle anterior cruciate ligament reconstruction: is the posterolateral bundle more important?

PURPOSE

The purpose of this study was to assess the pivot-shift phenomenon during double-bundle anterior cruciate ligament (ACL) reconstruction using a navigation system.

METHODS

Ninety patients who received navigated double-bundle ACL reconstruction were included in this study. The mean age of the patients was 21.9 years. During reconstruction, pivot-shift tests were performed 4 times: before reconstruction, after the posterolateral bundle fixation, after the anteromedial bundle fixation, and after the double-bundle reconstruction. Both tibial internal rotation and anterior translation under the pivot-shift test were measured at each phase by the additional functions of the navigation. The navigation system used in this study was the image-free, which does not require preoperative or intraoperative images, OrthoPilot ACL (version 2.0; B. Braun Aesculap, Tuttlingen, Germany).

RESULTS

Before ACL reconstruction, average (+/- standard deviation) tibial internal rotation and anterior translation under the pivot-shift test were 23.7 degrees +/- 6.1 degrees and 5.2 +/- 2.4 mm. They were significantly decreased to 20.9 degrees +/- 6.4 degrees and 2.3 +/- 1.1 mm after the posterolateral bundle fixation, and also decreased to 22.2 degrees +/- 5.7 degrees and 2.4 +/- 1.1 mm after the anteromedial bundle fixation. There was no significant difference between the groups. After double-bundle reconstruction, they improved to 20.3 degrees +/- 6.3 degrees and 2.0 +/- 1.0 mm.

CONCLUSIONS

Our results indicate that both the posterolateral and the anteromedial bundle similarly control both anterior translation and internal rotation during pivot-shift testing. Double-bundle reconstruction may further improve knee stability.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied reference gold standard.