Comparison of femoral tunnel position and angle with functional outcomes in arthroscopic anterior cruciate ligament reconstruction: Freehand drilling versus offset aimer technique

Objectives: To compare femoral tunnel position, graft angle, and short-term functional outcomes between freehand drilling and offset aimer techniques in arthroscopic anterior cruciate ligament reconstruction (ACLR). Materials and Methods: This prospective cohort study was conducted at a tertiary care teaching hospital from August 2022 to January 2024. Sixty-two patients with MRI-confirmed anterior cruciate ligament (ACL) tears underwent ACLR and were grouped by femoral tunnel technique: freehand drilling (n = 32) or offset aimer (n = 30). Postoperative 3D CT assessment was performed to evaluate femoral tunnel position and graft angle using the Bernard– Hertel grid. Functional outcomes were assessed using the Tegner–Lysholm Knee Score at 6 months. Results: The offset aimer group demonstrated significantly more posterior femoral tunnel placement on the X-axis compared to the freehand group (25.8 ± 4.3 vs 30.4 ± 10.1; p = 0.027) and a more acute graft angle (137.0° ± 3.7 vs 142.1° ± 12.1; p = 0.035). Variability was lower with the offset aimer, with coefficients of variation of 16.7% for X-axis position and 2.7% for graft angle, compared with 33.2% and 8.5% in the freehand group, respectively. Tegner– Lysholm scores at 6 months were comparable between groups (94.9 ± 4.3 vs 93.6 ± 5.7; p = 0.287). Conclusion: Both techniques achieved similar short-term functional outcomes after ACLR. However, the offset aimer provided more consistent femoral tunnel placement and graft angle. Longer-term studies are needed to determine whether improved tunnel placement consistency translates into superior graft survival and clinical outcomes.