Supplemental Fixation of Inner Graft Limbs in All-Inside, Quadrupled, Single-Tendon Anterior Cruciate Ligament Reconstruction Graft Construct Yields Improved Biomechanical Properties

Abstract

To compare the time-zero load to failure of a quadrupled, single-tendon, all-inside anterior cruciate ligament (ACL) reconstruction graft construct with (supplemented) and without the incorporation of inner-limb whipstitch sutures (control) into a tibial suspensory fixation button. Eight matched pairs of peroneus longus tendons were prepared according to a quadrupled, all-inside ACL soft-tissue graft technique with 1 side serving as a control and the contralateral side supplemented. The constructs were biomechanically tested for strain in the inner and outer limbs during a preconditioning protocol, single-cycle load to failure, and elongation of the whole construct. Ultimate load tofailure was significantly higher in the supplemented group: 797.5 ± 49.6N (95% confidence interval [CI], 763.13-831.87N) versus 719.6 ± 69.6N (95% CI, 671.38-767.82N; P= .044). Less graft elongation at failure was observed in the supplemented group (3.1 ± 1.5mm; 95% CI, 2.07-4.17mm) versus the control group (21.0 ± 21.2mm; 95% CI, 6.31-35.69mm; P= .052). The number of grafts undergoing a 5-mm or greater change in length at failure was 1 of 8 in the supplemented group versus 5 of 8 in the control group (P= .038). Inner-limb supplemental tibial fixation results in higher time-zero load to failure and decreased graft elongation in a quadrupled, single-tendon, all-inside ACL reconstruction graft construct. The weak point of a single-tendon, quadrupled, all-inside ACL graft construct is the tendon-to-tendon suturing to secure the inner limbs of the graft. Adding supplemental fixation by incorporating the sutures from the inner limb to the tibial suspensory fixation button leads to a higher time-zero load to failure and decreased graft elongation.