Tunnel placement in ACL reconstruction surgery: smaller inter-tunnel angles and higher peak forces at the femoral tunnel using anteromedial portal femoral drilling—a 3D and finite element analysis
Recent studies have emphasized the importance of anatomical ACL reconstruction to restore normal knee kinematics and stability. Aim of this study is to evaluate and compare the ability of the anteromedial (AM) and transtibial (TT) techniques for ACL reconstruction to achieve anatomical placement of the femoral and tibial tunnel within the native ACL footprint and to determine forces within the graft during functional motion. As the AM technique is nowadays the technique of choice, the hypothesis is that there are significant differences in tunnel features, reaction forces and/or moments within the graft when compared to the TT technique.
Twenty ACL-deficient patients were allocated to reconstruction surgery with one of both techniques. Postoperatively, all patients underwent a computed tomography scan (CT) allowing 3D reconstruction to analyze tunnel geometry and tunnel placement within the native ACL footprint. A patient-specific finite element analysis (FEA) was conducted to determine reaction forces and moments within the graft during antero-posterior translation and pivot-shift motion.
With significantly shorter femoral tunnels (p < 0.001) and a smaller inter-tunnel angle (p < 0.001), the AM technique places tunnels with less variance, close to the anatomical centre of the ACL footprints when compared to the TT technique. Using the latter, tibial tunnels were more medialised (p = 0.007) with a higher position of the femoral tunnels (p = 0.02). FEA showed the occurrence of higher, but non-significant, reaction forces in the graft, especially on the femoral side and lower, however, statistically not significant, reaction moments using the AM technique.
This study indicates important, technique-dependent differences in tunnel features with changes in reaction forces and moments within the graft.
Level of evidence
KeywordsAnterior cruciate ligament Reconstruction Transtibial Anteromedial Footprint 3D FEA
No funding was received for this study
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The study was approved by the ethical committee of the University Hospital of Ghent (EC UZG 2012/324–2013/375 - B670201317506).
- 5.Bischoff J (2008) Advanced material modeling in a virtual biomechanical knee. Abaqus Users’ conference. Newport, Rhode IslandGoogle Scholar
- 8.Desai N, Andernord D, Sundemo D, Alentorn-Geli E, Musahl V, Fu F, Forssblad M, Samuelsson K (2017) Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17.682 patients from the Swedish National knee ligament register. Knee Surg Sports Traumatol Arthrosc 25(5):1542–1554CrossRefGoogle Scholar
- 16.Rahr-Wagner L, Thillemann T, Pedersen A, Lind M (2013) Increased risk of revision after anteromedial compared with transtibial drilling of the femoral tunnel during primary anterior cruciate ligament reconstruction: results from the Danish knee ligament reconstruction register. Arthroscopy 29(1):98–105CrossRefGoogle Scholar