Notchplasty alters knee biomechanics after anatomic ACL reconstruction
- 25 Downloads
The aims of this study were (1) to study the biomechanics of single-bundle anatomic ACL reconstructed knees with and without notchplasty using a robotic testing system and (2) to determine if there would be a difference between performing a small or large notchplasty.
Fifteen fresh-frozen specimens were used in this study. The ACL reconstruction (ACL-R) was performed using an anatomic single-bundle technique with the 8 mm soft tissue graft fixed at 30° with suspensory fixation on the femoral side and a screw and washer on the tibial side. The notchplasty was then created with a burr. The following knee states were compared: (1) ACL-R, (2) ACL-R with a small (3 mm) notchplasty, and (3) ACL-R with a large (6 mm) notchplasty. Four loading conditions were applied: (1) an anterior drawer with an 89 N anterior tibial load, (2) simulated pivot-shift loading, (3) a 5 Nm internal rotational moment, and (4) a 5 Nm external rotational moment.
Under anterior tibial loading, anterior tibial translation increased, and graft force decreased significantly after ACL-R + 3 mm notchplasty and ACLR + 6 mm notchplasty compared to ACL-R alone at FE, 15° and 30° of knee flexion. There were no changes in either anterior tibial translation or graft force under simulated pivot-shift loading, internal rotational moment, or external rotational moment.
When added to anatomic ACL reconstruction, notchplasty increased anterior tibial translation and decreased graft forces during low knee flexion angles. There was no difference between a small and large notchplasty. The findings of this study are clinically relevant as the purpose of anatomic ACL reconstruction is to restore normal knee laxity, and while notchplasty may be helpful in avoiding graft impingement and improving visualization, removing even 3 mm of bone leads to biomechanical changes.
KeywordsNotchplasty Anatomic ACL Knee Biomechanics Robotic
The author did not receive any outside funding or grants directly related to the research presented in this manuscript. The author states that this manuscript is an original work only submitted to this journal. All authors contributed to the preparation of this work.
Compliance with ethical standards
Conflict of interest
Yongtao Mao MD: no conflict. Brandon Marshall MS: no conflict. Taylor Price BS: no conflict. Monica Linde MS: no conflict. Patrick Smolinski PhD: no conflict. Freddie H. Fu MD: no conflict. Carola F. van Eck MD PhD: no conflict.
Approval for this study was obtained from Committee for Oversight of Research and Clinical Training Involving Decedents (CORID).
- 33.Yasuda K, Ichiyama H, Kondo E, Miyatake S, Inoue M, Tanabe Y (2008) An in vivo biomechanical study on the tension-versus-knee flexion angle curves of two grafts in anatomic double-bundle anterior cruciate ligament reconstruction: effects of initial tension and internal tibial rotation. Arthroscopy 24:276–284CrossRefGoogle Scholar