Introduction

The quadriceps tendon (QT) graft can be used with or without a patellar bone block in anterior cruciate ligament reconstruction (ACLR). A suspensory button with suture loop has been used for 1-stranded QT soft-tissue graft fixation at femoral side; there is a concern that this connecting part might loosen when resisting the pull-out forces. However, the biomechanical strength of the fixation configurations using a suspensory button has not been fully investigated in the QT all soft-tissue graft. Therefore, the purpose of the present study was to compare the biomechanical strength of four different fixation configurations in all soft-tissue QT graft. The hypothesis was that QT graft fixation configurations with Group C (a continuous loop with suspensory button stitched directly to the QT with simple sutures) would have smaller cyclic elongation and higher maximum load to failure compared to other three configurations.

Material And Methods

The fresh-frozen forty bovine QT, with 6-cm length and 10-mm width, were allocated into four groups with different suture configurations using a suspensory button (n=10 in each group); Group A, baseball suture with knot tied to the continuous loop with suspensory button; Group B, same configuration as Group A but knot tied at opposite end of the baseball suture; Group C, a continuous loop with suspensory button stitched directly to the QT with eight simple sutures; Group D, 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.
One-way ANOVA was used to explore differences in elongation and maximum load to failure among four groups. Tukey test was used for post-hoc analysis. Statistical significance was set as P < 0.05.

Results

Group C showed significantly smaller elongation (4.1 ± 1.5 mm) than Group A (8.2 ± 1.7 mm), Group B (10.5 ± 3.9 mm), and Group D (8.5 ± 2.0 mm) (P < 0.01). The maximum load to failure in Group C (357 ± 106 N) was significantly higher than Group A (190 ± 70 N), Group B (215 ± 74 N), and Group D (212 ± 57 N) (P < 0.01). No significant differences were observed between Group A, B, and D in terms of elongation and maximum load to failure.

Conclusion

QT graft fixation configuration in Group C appears to be biomechanically superior among the four different configurations using a suspensory button. As clinical relevance, the Group C (a continuous loop with a suspensory button stitched directly to the QT with simple sutures) may be better for femoral fixation in ACLR from a biomechanical perspective.