## 4 Discussion  
In this exploratory study, the main findings were that (1) the HTT with LET diminishes ACLr graft stress more than HTT, TT, and AM without LET, and TT and AM with LET under medial rotation moment, and (2) for the AM portal, HTT, and TT techniques without LET show higher stress concentration patterns in the femoral tunnel. Thus, the HTT with LET FE model is suggested to be a surgical alternative to constrain isolated medial rotation moments during ACLr in agreement with [PERSON]'s principles for adding an LET technique [20; 32]. The LET technique based on soft tissue modeled here reduced the ACLr stress in three surgical choices (TT, HTT, and AM techniques) and shifted the stress concentration from the femoral tunnel for HTT with LET. The novelty of lower stress requirement and better stress distribution for HTT with LET found here would impact surgery costs, time of surgery and planning [17], complications associated with fixation elements during rehabilitation [21; 22], and the risk of tunnel coalition [24]. Thus, it might be a better surgical design for single-bundle ACLr than TT and AM. Our findings gave insight into differentiating the ACLr stress distribution and concentration between HTT, TT, and AM with and without LET to constrain excessive medial knee rotation in the same direction as previous clinical and preclinical findings using LET with fixation elements found [32; 33]. The simulated LET technique here would be an alternative for sport and exercise movements involving directional changes and pivoting [34], as it necessitates medial knee rotation. The absence of LET may lead to increased stress concentration at the femoral tunnel, tunnel enlargement, and, consequently, altered tibial stress displacement, potentially contributing to long-term tibial osteoarthritis. In this study, it was found that the HTT with LET diminishes the maximal stress of ACLr grafts (\(\Delta\) = 97%) more than TT (\(\Delta\) = 93%) and AM (\(\Delta\) = 86%) with LET under a medial rotation moment. Other LET techniques (non-soft tissue LET [16]) reported a 43% graft stress reduction [18]. The stress reduction in our study establishes that when the ACLr femoral tunnel varied from the AM to TT technique combined with LET under medial knee rotation, the ACLr graft stress changed from higher values due to a more deflected graft in the coronal and sagittal plane to lower values due to a more verticalized ACLr graft, in agreement with past analysis [13; 32; 33]. The HTT is a femoral tunnel choice within the spectrum of all possible tunnels between the AM and TT techniques, with the HTT being a surgical alternative to the TT technique. Our study showed how the femoral condyle is constrained under medial knee rotation internally at the ACLr footprint and externally at the lateral condyle septum by the ACLr graft and LET [35]. Hence, a more deflected graft derived from an AM tunnel tightens the ACLr graft more than the TT technique, suggesting that the HTT femoral tunnel and LET diminish the ACLr graft stress. Additionally, the biomechanical superiority of adding LET to constrain knee movements following an ACLr is in agreement with past reports [32; 33]. However, it is important to indicate that an unbalanced ACLr and LET would change our findings i.e., a shortened ACLr graft and lengthened LET. Thus, the tightened balance for the ACLr graft and LET ought to be considered during the surgery plan. In the case of the iliocibial band-intermuscular septum LET technique, a key point for surgeons is not to overconstrain LET, and it is recommended not to apply too much tension and always check that the full range of motion is permitted before closure distally [23]. Real-time fluoroscopy of the medial knee rotation might provide good feedback on how the lateral condyle displaces over the tibia to adjust the LET tension.