INTRODUCTION: The aim of this study was to assess the differential laxity after reconstruction of the anterior cruciate ligament (ACL) by the TLS® technique using a single tendon, the semitendinosus in four-strand graft, compared with the hamstring technique which uses both the gracilis and semitendinosus. We hypothesised that this surgical technique would provide post-surgical differential laxity measurements at least as good as those of the hamstring technique. MATERIALS AND METHODS: We carried out a prospective monocentric study on patients undergoing unilateral anterior cruciate ligament repair between December 2014 and June 2016. All patients were followed up for at least 12 months. The series compares 61 patients operated on using the TLS® technique by the same surgeon, with 33 patients operated on using the hamstring technique by a second surgeon. The main objective of the study was to compare the post-operative differential laxity, measured using the KT1000, between the two techniques. RESULTS: There was no significant difference in the patients' epidemiological characteristics and pre-operative scores between the two groups. Average pre-operative differential laxity was 6.5 mm ± 2.1 (min 3; max 12) in the TLS group and 6.4 mm ± 2.0 (min 0; max 11) in the hamstring group, with no statistically significant difference. The average post-operative difference in laxity was - 0.1 mm ± 1.9 (min - 5; max 4) in the TLS group and 0.3 mm ± 2.0 (min - 7; max 5) in the hamstring group. Again, no significant difference was observed between groups. DISCUSSION: This study demonstrates a level of post-operative differential laxity control using TLS comparable with that of the ACL reconstruction technique using a hamstring graft with preserved tibial insertion