Effect of tibial drill-guide angle on the mechanical environment at bone tunnel aperture after anatomic single-bundle anterior cruciate ligament reconstruction

Abstract

Purpose The tibial drill-guide angle in anterior cruciate ligament (ACL) reconstruction influences the tunnel placement and grafttunnel force, and is potentially associated with post-operative tunnel widening. This study aimed to examine the effect of the drill-guide angle on the stress redistribution at the tibial tunnel aperture after anatomic single-bundle ACL reconstruction. Methods A validated finite element model of human knee joint was used. The tibial tunnel with drill-guide angle ranging from 30°to 75°was investigated. The post-operative stress redistribution in tibia under the compressive, valgus, rotational and complex loadings was analysed.Results Compressive loading played a leading role on the stress redistribution at intra-articular tibial tunnel aperture. After ACL reconstruction, stress concentration occurred in the anterior and posterior regions of tunnel aperture while stress reduction occurred in the lateral and posteromedial regions under the compressive loading. Stress redistribution was partially alleviated by using the drill-guide angle ranging from 55°to 65°. Conclusions The present study quantified the effect of bone tunnel drill-guide angle on the post-operative stress redistribution. This phenomenon potentially contributed to tunnel widening. A tunnel drill-guide angle ranging from 55°to 65°was proposed based on the biomechanical rationale. It could serve as a helpful surgical guide for ACL reconstruction.

The Femoral Tunnel Drilling Angle at 45° Coronal and 45° Sagittal Provided the Lowest Peak Stress and Strain on the Bone Tunnels and Anterior Cruciate Ligament Graft

“…Several studies (Schechtman and Bader, 1997;Jagodzinski et al, 2005;Yao et al, 2014;Srinivas et al, 2016;Srinivas et al, 2016) have investigated the factors that might cause tunnel enlargement and graft failure. Srinivas et al (Srinivas et al, 2016) found that the enlargement of femoral tunnel and tibial tunnel varied with different methods of fixation.…”

“…Schechtman et al (Schechtman and Bader, 1997) reported a linear relationship between the stress and the number of cycles of tendons to fatigue failure. Few studies demonstrated that tunnel orientation might influence tunnel enlargement and graft failure (Jagodzinski et al, 2005;Yao et al, 2014). Specifically, Yao et al (Yao et al, 2014) quantified the effects of tibial tunnel drill-guide angle on the stress redistribution at the tibial tunnel aperture after ACLR, which potentially contributed to the tibial tunnel widening.…”

Changing the Diameter of the Bone Tunnel Is More Effective Than Changing the Tunnel Shape for Restoring Joint Functionality After ACL Reconstruction

“…To simulate conventional ACLR, the original ACL was removed, and the femoral and tibial tunnels (diameter 7.5 mm) were created through the center of ACL insertion sites. The angles between the femoral tunnel axis and the axial and sagittal planes were 45 • and 25 • , respectively, and the angles between the tibial tunnel axis and the axial and sagittal planes were 65 • and 25 • , respectively (Yao et al, 2014). A four-strand hamstring tendon graft was simulated as being cylindrical in shape with a diameter of 7.5 mm and stiffness of 776 N/mm (Hamner et al, 1999).…”

Current Strategies and Future Directions to Optimize ACL Reconstruction in Adolescent Patients

“…Pena et al have previously shown the angle of the femoral tunnel primarily affects tension of the graft, while the tibial tunnel significantly affects laxity and meniscal stresses ( 35 ). For example, tibial drill-guide angles between 55 and 65 degrees have been proposed as optimal angles for proper stress redistribution ( 36 ). Moreover, the graft tension is vitally important as enough tension is required to maintain stability, while a mechanism has been proposed where too much tension leads to physeal compression and ultimately damage ( 33 ).…”