To determine if the anteromedial portal (AMP) is better than transtibial approach (TT) in terms of clinical function, knee joint stability, femoral tunnel length and location.

From August 2010 to July 2013 , 104 patients who underwent anterior cruciate ligament reconstruction in Yantai Yuhuangding Hospital were enrolled. Inclusion criteria: at least one year post-operative follow-up, normal contralateral knee joint, no serious postoperative complications, and postoperative three-dimensional reconstruction CT imaging data can be obtained. Exclusion criteria: combining anterior and posterior cruciate ligaments injury, accompanying collateral ligament injury, osteoarthritis and revision surgery. The patients were randomly divided into two groups: 56 patients in the AMP group including 46 males and 10 females, mean age was (30±12) years; 48 patients in the TT group including 40 males and eight females, mean age was (32±11) years. All the patients were assessed by Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner score pre-operatively and at last follow-up. All the patients underwent Lachman test, Pivot-shift test and KT-1000 evaluation at the last follow-up. The length of femoral tunnel was measured intraoperatively; one week after the operation, 3D-CT anatomical reconstruction was performed to assess the location of the femoral tunnel. Unpaired ttest and Mann-Whitney rank test (non-parametric test of two independent samples) were used statistical comparisons.

The mean follow-up time of the AMP group was (26±7) months, and the average follow-up time of the TT group was (25±6) months. There was no statistically significant difference in Lysholm score(pre-operation t=0.347, P>0.05; last follow-up t=1.557, P >0.05), IKDC score(pre-operation t=-0.383, P >0.05; last follow-up t=1.102, P >0.05) or Tegner score(pre-operation t=0.283, P >0.05; last follow-up t=1.763, P >0.05) between the two groups before the operation or at the last follow-up. In Lachman test(Z=-0.482, P>0.05), Pivot-shift test (Z=-1.455, P >0.05)and KT-1000(t=-0.750, P>0.05), there was no statistically significant difference between the two groups at the last follow-up. The mean femoral tunnel length in the AMP group was significantly shorter than that in the TT group (t=-5.554, P<0.01). Tunnel location was significantly lower (t=8.865, P<0.01) and deeper (t=-4.508, P<0.01)with the AMP technique than with the transtibial method.

Clinical function and knee joint stability are similar in AMP and TT; however, AMP has a shorter femoral tunnel than TT of which the location is deeper, lower, and closer to the femoral footprint.