Abstract:Objective To compare the effects of arthroscopic anterior cruciate ligament reconstruction using outside-in technique and trans-inferior anteromedial approach in arthroscopic anterior cruciate ligament reconstruction on postoperative bone tunnel enlargement.Methods A retrospective analysis of 50 patients were diagnosed with anterior cruciate ligament injury from February 2018 to June 2019 were divided into two groups with anterior cruciate ligament reconstruction. 25 patients used the femoral tunnel from the outside-in technique to drill the femoral tunnel, and the remaining 25 patients used the traditional anteromedial approach, and routinely recovered after the operation. The enlarged diameter of femoral and tibial tunnels and Lysholm score were compared one year after operation.Results All the patients were followed up 1 year after surgery. The results of the postoperative follow-up showed that there were 13 patients with bone tunnel enlargement. The enlargement diameter of femoral tunnel from the outside-in group was (2.21 ± 1.69) mm, and the femoral tunnel for the anteromedial approach group. The enlargement diameter was (1.54 ± 1.14) mm, and the difference was statistically significant (P < 0.05). The enlargement diameter of the tibial tunnel from the outside to the inside group was (1.61 ± 1.42) mm, and the anteromedial approach group was (1.70 ± 1.22) mm, the difference was not statistically significant (P > 0.05). The Lysholm score from the outside-in group was (96.73 ± 3.92) and the anteromedial group was (96.29 ± 3.71) at 1 year after surgery, the difference was not significant (P > 0.05); The Lysholm score of grade 0 bone tunnel enlargement was (96.51 ± 3.89), grade 1 enlargement was (94.89 ± 3.47), grade 2 enlargement was (92.21 ± 0.59), and the difference was not significant (P > 0.05).Conclusion One year after operation , two kinds of femoral tunnel drilling methods can cause bone tunnel expansion, the diameter of femoral tunnel enlargement is significantly related to the femoral tunnel drilling method, and whether the tunnel expansion has no significant effect on knee function .