Tibial tunnel widening after hamstring anterior cruciate ligament reconstructions: comparison between Rigidfix and Bio-TransFix.

BACKGROUND

There is no study comparing tibial tunnel widening after hamstring anterior cruciate ligament (ACL) reconstructions between RigidFix(r) and Bio-TransFix(r).

METHODS

Hamstring ACL reconstructions using RigidFix(r) in 56 patients and Bio-TransFix(r) in 41 with a minimum of 2years 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.

RESULTS

On the AP and lateral radiographs, the average diameter of the tibial tunnel in the Bio-TransFix(r) group significantly increased after 6months 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 6months compared to the immediate postoperative measurement. Tunnel widening at 12months 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 24months 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.

CONCLUSION

The Bio-TransFix(r) group showed progressive tibial tunnel widening after 6months postoperatively but no clinical signs of instability.

LEVEL OF EVIDENCE

Level III.