Biomechanical study of posterior cruciate ligament tibial arrest avulsion fracture fixation with triple tibial channel net sutures

To investigate the biomechanical properties of posterior cruciate ligament avulsion fractures of the tibia fixed using four different methods, including triple tibial channel net suture fixation. In 40 porcine knees, a standardized bony avulsion of the posterior cruciate ligament was generated. Double tibial bone channel suture fixation was performed in group A, double-head hollow compression screw fixation was performed in group B, triple tibial bone channel net suture fixation was performed in group C, and cortical suspension EndoButton fixation was performed in group D. The constructs were cyclically loaded 500 times (10 to 100 N) to measure the initial displacement and stiffness values. Subsequently, loading to failure was performed, and the yield load and peak load were measured. The results were analysed by one-way ANOVA, with significance set at P < 0.05. The initial displacement in group D (1.00 ± 0.20 mm) was lower than that in group C (1.46 ± 0.33 mm, P = 0.000), group B (1.91 ± 1.71 mm, P = 0.000) and group A (3.91 ± 0.79 mm, P = 0.000), but there was no significant difference between groups B and C (P = 0.055). The initial stiffness in group A (50.59 ± 6.89 N/mm) was lower than that in group C (67.21 ± 12.80 N/mm, P = 0.001), group D (71.18 ± 9.20 N/mm, P = 0.000) and group B (78.67 ± 5.91 N/mm, P = 0.000). However, there was no significant difference between groups B and D or between groups C and D (P = 0.111 and P = 0.391). The yield load in group A (554.86 ± 71.43 N) was lower than that in group C (767.00 ± 34.53 N, P = 0.000), group D (777.62 ± 73.03 N, P = 0.000) and group B (837.50 ± 55.73 N, P = 0.000). There was no significant difference between groups C and D (P = 0.729). The peak load in group A (667.38 ± 61.54 N) was lower than that in group C (842.00 ± 26.20 N, P = 0.000), group D (867.63 ± 63.42 N, P = 0.000) and group B (901.25 ± 54.38 N, P = 0.000). There was no significant difference between groups C and D (P = 0.346). Different failure modes were found among the four groups. The triple tibial bone channel suture fixation group showed better initial stability and fixation strength, which was comparable to that in the cortical suspension EndoButton fixation group and double-head hollow compression screw fixation group and significantly stronger than that in the double tibial bone channel suture fixation group. This study analysed the dynamic and static indexes of posterior cruciate ligament tibial avulsion fractures fixed by four different fixation methods under cyclic loading tests and single failure loading tests, providing a theoretical basis for clinical treatment.