Background: The restoration of knee rotational stability after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction has been demonstrated in the cadaveric model and with passive stress tests on humans but not yet with dynamic functional biomechanical tests performed by human participants.
Purpose: To prospectively investigate the range of tibial rotation of ACL-deficient and ACL-reconstructed knees during a pivoting task. The authors hypothesized that there would be a significant increase in tibial internal rotation in the ACL-deficient knee compared with the contralateral knee and that the increased rotation would return to normal after anatomic double-bundle ACL reconstruction.
Study Design: Case series; Level of evidence, 4.
Methods: Ten men with unilateral ACL injury performed a high-demand jump-landing and pivoting task before and after ACL reconstruction with mean follow-up of 11 months. The range of tibial rotation of the injured, reconstructed, and intact knees during the pivoting movement was measured by an optical motion analysis system. Paired t tests were performed to investigate any significant difference between the 2 limbs preoperatively and postoperatively and within the injured limb before and after the surgical treatment. Statistical significance was set at P < .05.
Results: The range of tibial rotation was higher in the ACL-deficient knee (12.6° ± 4.5°) than in the intact knee (7.9° ± 3.1°) preoperatively (P < .05). The increased rotation was reduced in the reconstructed knee (8.9° ± 3.0°) after ACL reconstruction versus the intact knee postoperatively (8.2° ± 2.6°) (P < .05). There was no significant difference in the tibial rotation between the intact knee and the reconstructed knee postoperatively (P > .05).
Conclusion: As assessed with a dynamic functional pivoting movement, the anatomic double-bundle ACL reconstruction successfully restores knee rotational stability from an impaired level.
Background: The biomechanical function of single-bundle anterior cruciate ligament reconstruction, in cadaveric studies, is successful in limiting anterior tibial translation in response to an anterior tibial load but seems to be insufficient to control a combined rotator load of internal and valgus torque. Anatomical double-bundle anterior cruciate ligament reconstruction might produce a better biomechanical outcome.
Hypothesis: The addition of the posterolateral bundle to the anteromedial bundle, in an in vivo double-bundle computer-assisted anterior cruciate ligament reconstruction, is able to reduce internal rotation of the tibia at 30° of knee flexion, compared with a standard single-bundle reconstruction.
Study Design: Controlled laboratory study.
Methods: Twenty consecutive anterior cruciate ligament reconstructions were performed in male patients in April and May 2006 with double-bundle gracilis and semitendinosus tendon grafts using the 2.0 OrthoPilot navigation system. Group A (10 patients) underwent standard single-bundle anterior cruciate ligament reconstruction with doubled gracilis and semitendinosus tendon graft; group B (10 patients) underwent double-bundle reconstruction with doubled gracilis and semitendinosus tendon graft. Anteroposterior displacement and internal and external rotation at 30° of knee flexion were evaluated before and after reconstruction, using manual maximum force.
Results: Both techniques significantly reduced anteroposterior displacement and internal and external rotation of the tibia with respect to preoperative anterior cruciate ligament–deficient condition (P < .05). Comparing groups, no differences in anteroposterior tibial displacement and internal and external rotation of the tibia were found (anteroposterior, 3.7 mm and 5.2 mm; internal rotation, 16.3° and 16.6°; external rotation, 15.7° and 15.1°, respectively) in group A and B (P = .06, .90, and .72, respectively).
Conclusion: The hypothesis that addition of the posterolateral bundle to the anteromedial bundle is able to reduce internal rotation of the tibia at 30° of knee flexion is not confirmed.
Clinical Relevance: The effective role of the anatomical double-bundle procedure in better restoring knee kinematics should be questioned in an in vivo model.
