The effect of remnant preservation on tibial tunnel enlargement in ACL reconstruction with hamstring autograft: a prospective randomized controlled trial

To investigate the effect of remnant preservation on tibial tunnel enlargement in a single-bundle anterior cruciate ligament (ACL) reconstruction with a hamstring autograft. From 2006 to 2009, a total of 62 patients who underwent single-bundle ACL reconstruction with a quadrupled hamstring tendon autograft were enrolled in this study. The patients were randomly divided into two groups: the preserving-remnant group and the removing-remnant group. Plain radiographs were taken at 1 week, and 3, 6, and 24 months postoperatively, and tibial tunnel enlargement was evaluated. The postoperative clinical assessment included the Lysholm rating scale and KT-1000 measurement. In total, 27 patients in the preserving-remnant group and 24 patients in the removing-remnant group were followed up and the median follow-up was 24.5 months (range 24-27 months). Tibial tunnel enlargement occurred within 6 months postoperatively. Positive enlargement was observed in 8 patients (29.6 %) in the preserving-remnant group and 14 patients (58.3 %) in the removing-remnant group (P = 0.0388). The percentage of tibial tunnel enlargement was 25.7 +/- A 6.7 and 34.0 +/- A 8.9 % in the preserving- and removing-remnant groups, respectively (P = 0.0004). In the preserving-remnant group, the average Lysholm score increased from 60.3 +/- A 5.3 (51-69) to 93.0 +/- A 3.5 (88-100), and the side-to-side difference of the KT-1000 changed from 6.3 +/- A 0.9 (5.1-8.0) to 1.4 +/- A 0.6 (0.5-2.4) mm. In the removing-remnant group, the average Lysholm score increased from 58.7 +/- A 6.5 (48-71) to 91.1 +/- A 3.9 (85-100), and the side-to-side difference of the KT-1000 changed from 6.5 +/- A 0.8 (5.4-8.2) to 1.7 +/- A 0.6 (0.6-2.8) mm. It is confirmed that remnant preservation in ACL reconstruction can resist tibial tunnel enlargement but that this technique does not affect the short-term clinical outcome of ACL reconstruction. I.