Summary
In cases with ACL and lateral meniscus injuries, additional centralization procedure further controls pivot shift after ACL reconstruction and lateral meniscus repair; in such cases where surgeon considers as a high-risk patient, additional centralization procedure can be one option to relatively easily and less invasively control anterolateral stability.
Abstract
Background
It has been reported that lateral meniscus (LM) is an important secondary restraint against anterolateral instability in patients with ACL injuries. However, degrees of contribution between ACL and LM have yet to be clarified. In addition, in cases with LM disorders concomitant with ACL injury, if LM repair alone can fully restore the function to control anterolateral stability has not been determined clinically. Nakamura et al. showed that incases involving irreparable LM injuries during ACL reconstruction (ACLR), centralization procedure could reduce knee laxity after ACLR in a cadaveric model. Therefore, the purpose of this study was to investigate if additional centralization procedure could further restore the LM function to control anterolateral stability after ACLR and LM repair, by evaluating degrees of changes in pivot shift among ACLR alone, after LM repair and after additional centralization in patients with ACLR. We hypothesized that additional centralization procedure further controls pivot shift after ACLR and LM repair.
Methods
Sixteen patients who underwent primary double-bundle ACLR using hamstring tendons concomitantly with LM repair were included. The pivot shift test was performed preoperatively for both knees, and during surgery after ACLR [under two conditions, with initial tension of 5 N for both anteromedial and posterolateral bundles (A5P5), and initial tension of 10 N for both bundles(A10P10)], after LM repair and after centralization with acceleration measurements using a triaxial accelerometer.
Results
In the A5P5 condition, ACLR alone could not reduce the pivot shift acceleration to the contralateral knee level (ACLR alone: 4.9 ± 1.6 m/s2, control: 4.7 ± 1.0 m/s2), whereas additional LM repair reduced the acceleration below the contralateral knee level (after LM repair: 3.9 ± 0.9 m/s2). Additional centralization further reduced the acceleration significantly less than ACLR + LM repair alone (after centralization: 2.8 ± 0.9 m/s2, p < 0.001). In the A10P10 condition, ACLR alone could reduce the pivot shift acceleration to the contralateral knee level (ACLR alone: 4.5 ± 1.5 m/s2, control: 4.7 ± 1.0 m/s2). LM repair and additional centralization further reduced the acceleration significantly less than ACLR alone (after centralization: 2.8 ± 0.8 m/s2, p < 0.001), whereas ACLR + LM repair alone did not (after LM repair: 3.5 ± 1.0 m/s2, p = 0.07).
Discussion And Conclusion
additional centralization procedure further controls pivot shift after ACLR and LM repair. In cases with high-risk patients for graft failure and residual pivot shift, recent trend has been toward additional anterolateral structure augmentation (e.g., anterolateral ligament reconstruction and lateral extra-articular tenodesis). On the other hand, LM centralization procedure has been proven to control rotational knee laxity by stabilizing capsule of the lateral side. In cases with ACL and LM injuries where surgeon considers as a high-risk patient, additional centralization procedure can be one option to relatively easily and less invasively control anterolateral stability.