Double tibial tunnels ‘supra’ over‐the‐top anterior cruciate ligament reconstruction with lower initial graft tension achieves comparable anterior stability to single‐tunnel: A cadaveric study using a robotic simulator

Purpose To compare the anterior tibial translation (ATT) between single‐bundle (SB) and double‐bundle (DB) ‘supra’‐over‐the‐top anterior cruciate ligament reconstruction (s‐OTT ACLR) during the anterior drawer test in a cadaveric model. Methods This was a controlled laboratory study. Seven fresh‐frozen cadaveric knee specimens and a robotic testing system were used. Initially, the same testing procedure (100 N anterior drawer load applied at 0°, 15°, 30°, 60° and 90° of knee flexion) was applied to the following four different knee conditions: intact, anterior cruciate ligament (ACL)‐sectioned, SB s‐OTT ACLR and DB s‐OTT ACLR knees. Subsequently, a combined load of 5 Nm internal tibial torque and 10 Nm valgus torque was applied at 15° and 30° of knee flexion as a simulated pivot shift. During the tests, anterior tibial translation (ATT) was recorded. The initial tension was set at 22 N for the SB s‐OTT ACLR and 11 N for each graft in the DB s‐OTT ACLR at 30° of knee flexion. For the SB s‐OTT ACLR with an 8‐mm‐diameter tibial tunnel, the drilling area was 16 Π mm² (4 × 4 × Π). Regarding the DB s‐OTT ACLR with two 5‐mm‐diameter tibial tunnels, the total drilling area was 12.5 Π mm² (2.5 × 2.5 × Π × 2). Results Both SB and DB s‐OTT ACL reconstructions significantly reduced ATT compared with the ACL‐sectioned state under both anterior drawer and simulated pivot‐shift loads, while showing no difference from the intact knee. No significant ATT difference was detected between SB and DB s‐OTT ACLRs at any tested flexion angle, and DB achieved anterior knee stability comparable to SB despite its lower initial graft tension. Conclusions DB s‐OTT ACLR demonstrated ATT and in situ graft force comparable to SB s‐OTT ACLR in a cadaveric robotic study. These findings suggest that DB s‐OTT ACLR can achieve anterior knee stability similar to SB s‐OTT ACLR with lower initial graft tension. Level of Evidence N/A.