Biomechanical Evaluation of Knee Kinematics after ACL Reconstructions in Anatomic SB and DB - Technique with Additional Medial Meniscus Suture

OBJECTIVES: Biomechanical evaluation of knee laxity after single- and double-bundle ACL reconstruction with additional medial meniscus suture. METHODS: Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a bucket-handle tear of the medial meniscus. A standard repair of the medial meniscus was performed using 3 inside-out horizontal sutures. Finally, The ACL was reconstructed using an anatomic single-bundle (6) or double-bundle technique (6). Knee kinematics were determined following every sub-step. RESULTS: Significant increase of aTT in the ACL-deficient knee was found with significant increase in the ACL-deficient knee with additional medial meniscal injury (p=.003; p=.009). ACL reconstructions significantly decreased aTT compared to the ACL-deficient knee. No significant differences were found between the intact knee and the ACL reconstructed knee with additional meniscal repair. In response to a simulated pivot shift, aTT in the intact knee significantly increased in the ACL-deficient knee as well as in the meniscus injured/meniscus-sutured knee (p=.003;p=.007). No significant differences were found between the ACL-deficient and ACL reconstructed knee with additional meniscal repair. SB as well as DB ACL reconstruction with additional medial meniscal repair restored knee kinematics compared to the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences neither in a simulated Lachman test nor in response to a simulated pivot shift (p=.05). CONCLUSION: aTT as well as aTT in response to a combined rotatory load significantly increased with ACL deficiency compared to the intact knee, additional medial meniscal injury further increased aTT. Anatomic ACL reconstruction with medial meniscal repair restored knee kinematics compared to the intact knee. Comparison of anatomic SB vs. DB ACL reconstruction with additional repair of the medial meniscus did not reveal significant differences in aTT as well as aTT under a combined rotatory load.