Tibial tunnel widening after hamstring anterior cruciate ligament reconstructions: Comparison between Rigidfix and bio-Transfix

BackgroundThere is no study comparing tibial tunnel widening after hamstring anterior cruciate ligament (ACL) reconstructions between RigidFix(r) and Bio-TransFix(r).MethodsHamstring ACL reconstructions using RigidFix(r) in 56 patients and Bio-TransFix(r) in 41 with a minimum of 2 years postoperative evaluation were reviewed. Tibial fixation was performed using Intrafix in both groups. On the anterior–posterior (AP) and lateral radiographs, the diameter of the tibial tunnel was measured at proximal, middle, and distal positions. Postoperative laxity evaluations were performed using Lachman test, pivot-shift test, and instrumented laxity testing using the KT-1000 arthrometer.ResultsOn the AP and lateral radiographs, the average diameter of the tibial tunnel in the Bio-TransFix(r) group significantly increased after 6 months compared to the immediate postoperative measurement (p = 0.002 and p = 0.002, respectively). However, the average diameter of the tibial tunnel in the RigidFix(r) group did not increase after 6 months compared to the immediate postoperative measurement. Tunnel widening at 12 months postoperatively in the Bio-TransFix(r) group was significantly more than that of the RigidFix(r) group on AP and lateral radiographs (p = 0.012 and 0.016, respectively). Tunnel widening at 24 months postoperatively showed a significant difference between the two groups (p = 0.000 and 0.000, respectively). Fifteen patients (36.6%) in the Bio-TransFix(r) group and 15 patients (26.8%) in the RigidFix(r) group showed tunnel widening. There were no significant differences in results of the Lachman and pivot-shift tests, and mean KT-1000 measurement between the two groups.ConclusionThe Bio-TransFix(r) group showed progressive tibial tunnel widening after 6 months postoperatively but no clinical signs of instability.Level of evidenceLevel III.