Comparison of femoral oval tunnel technique and round tunnel technique in single-bundle anterior cruciate ligament reconstruction

Abstract

To evaluate the effectiveness of femoral oval tunnel technique versus round tunnel technique in single-bundle anterior cruciate ligament (ACL) reconstruction. Between March 2016 and February 2018, 125 patients who underwent anatomical single-bundle ACL reconstruction with hamstring tendon and met the inclusive criteria were included in the retrospective study. Of the included patients, 43 patients underwent ACL reconstruction using oval tunnel technique (group A) and 82 patients with round tunnel technique (group B). There was no significant difference between the two groups in terms of age, gender, body mass index, the interval between injury and operation, the injured side, the cause of injury, and preoperative Lysholm score, International Knee Documentation Committee (IKDC) score, Tegner score, and the outcome of KT-1000 measurement ( P>0.05). At 3, 6, 12, and 24 months after operation, the knee function scores (Lysholm score, IKDC score, Tegner score) were recorded; and KT-1000 was used to evaluate the knee stability. The position and shape of the tunnels were evaluated by the three-dimensional CT (3D-CT) at 1 day after operation; and MRI was performed at 6, 12, and 24 months to calculate the signal/noise quotient (SNQ) of ACL grafts. Secondary arthroscopy was conducted to estimate the graft status, synovial coverage, and tension. All patients were followed up 12-26 months (mean, 23 months). Two patients in group A and 5 patients in group B presented with redness and swelling of the surgical site, 1 patient in group B sustained a tibial tunnel fracture, and 1 patient in group A had postoperative stiffness. The Lysholm score, IKDC score, and Tegner score were significantly higher in group A than in group B at the different time points ( P<0.05) except for the Tegner score at 3 months. The outcomes of KT-1000 measurement were significantly lower in group A than in group B ( P<0.05). The entrances of the femoral tunnel and tibial tunnel in both groups were within the ACL anatomical footprint confirmed by 3D-CT. No re-rupture of ACL occurred confirmed by the MRI. There was no significant difference in SNQs of the middle and distal grafts between the two groups at 6 months ( P>0.05), whereas the SNQ of the proximal grafts in group A was significantly lower than that in group B ( P<0.05). The SNQs of the proximal, middle, and distal grafts in group A were significantly lower than those in group B at 12 and 24 months after operation ( P<0.05). Twenty-one patients in group A and 38 patients in group B underwent secondary arthroscopy and the results showed no significant difference in graft status, synovial coverage, and tension between the two groups ( P>0.05). The effectiveness and graft maturity of the femoral oval tunnel technique were superior to the round tunnel technique. The single-bundle ACL reconstruction with femoral oval tunnel technique can obtain a better knee function.