Direct suturing quadriceps tendon to a continuous loop with a suspensory button provides biomechanically superior fixation in ACL reconstruction

Purpose To compare the biomechanical strength of different fixation configurations using suspensory buttons in a soft-tissue quadriceps tendon (QT) grafts in anterior cruciate ligament (ACL) reconstruction. Methods Forty bovine QTs, 6-cm long and 10-mm wide, were allocated into four groups with different suture configurations using suspensory buttons ( n = 10 in each group): Group A, a baseball suture with a knot tied to the continuous loop with a suspensory button; Group B, same configuration as in Group A but with the knot tied at the opposite end of the baseball suture; Group C, a continuous loop with a suspensory button stitched directly to the QT with simple sutures, and Group D, a baseball suture tied directly to a suspensory button. Biomechanical testing was performed by preloading followed by cyclic loading for 500 cycles between 10 and 100 N. The length of elongation (mm) and maximum load to failure (N) were recorded, and compared among the four groups. Results Group C showed significantly smaller elongation (4.1 mm [95% CI 3.1–5.2]) than Group A (8.2 mm [95% CI 7.0–9.4]), Group B (10.5 mm [95% CI 7.7–13.3]), and Group D (8.5 mm [95% CI 7.0–9.9]) (A–C; P = 0.004, B–C; P = 0.0001, C–D; P = 0.0018). The maximum load to failure in Group C (386 N [95%CI 306–466]) was significantly higher than that in Group A (196 N [95% CI 141–251]), Group B (226 N [95% CI 164–289]), and Group D (212 N [95%CI 171–253]) (A–C; P = 0.0001, B–C; P = 0.0009, C–D; P = 0.0002). No significant differences were observed between Group A, B, and D in terms of elongation and maximum load to failure. Conclusion The soft-tissue QT graft fixation configuration stitched directly to a continuous loop with suspensory button using simple sutures exhibits small elongation and high maximum load to failure among the four configurations. Regarding clinical relevance, direct suturing of the soft-tissue QT to a continuous loop with a suspensory button may be advantageous for femoral fixation in ACL reconstruction from a biomechanical perspective, and warrant future development of a novel fixation device using this principle.