Biomechanical effects of cross-pin's diameter in reconstruction of anterior cruciate ligament – A specific case study via finite element analysis

•The effects of different diameter of fixators in graft fixation for anterior cruciate ligament reconstruction (ACL-R) remain unknown and require further investigation.•Different diameters of cross-pin (4 mm, 5 mm and 6 mm) with fixed length of 50 mm were investigated to analyse the relationship between the size of the fixators and their mechanical stabilities in graft fixations that correlates with biomechanical behaviors of bones.•Localised parameters such as stress and strain by means of finite element analysis are analysed under 100 N anterior tibial load.•A 4 mm cross-pin provided optimum fixation stability with lower stresses at fixators than the other two cross-pins with 28% difference, offered favourable biomechanical environment for osseointegration and minimize the possibility of breakage and migration of fixators. For anterior cruciate ligament reconstruction (ACL-R), one of the crucial aspects of treatment is the fixator selection that could provide initial graft fixation post-operatively. Literature on biomechanical stabilities of different sizes of fixators as femoral graft fixation is limited. Therefore, this study aims to analyse the influence of different diameters of cross-pins on the stability of graft fixations after ACL-R via finite element analysis (FEA). In the methodology, three-dimensional (3D) models of three different diameters of cross-pins were developed, of which anterior tibial loads (ATL) were applied onto the tibia. From the findings, the cross-pin with a smaller diameter (4 mm) provided optimum stability than larger diameter cross-pins, whereby it demonstrated acceptable stresses at the fixators (both cross-pin and interference screw) with a different percentage of 28%, while the stresses at the corresponding bones were favourable for osseointegration to occur. Besides, the strains of the knee joint with 4 mm diameter cross-pin were also superior in providing a good biomechanical environment for bone healing, while the recorded strain values at fixators were comparable with a larger diameter of cross-pins without being inferior in terms of deformation. To conclude, the cross-pin with 4 mm diameter depicted the best biomechanical aspects in graft fixation for ACL-R since it allows better assistance for the osseointegration process and can minimise the possibility of the breakage and migration of fixators. This study is not only useful for medical surgeons to justify their choices of pin diameter to treat patients, but also