Biomechanical Study Of Suture Thread Used In Panda Rope Bridge Technique

Objective: To compare the biomechanical properties of two representative strong sutures(Ethibond and Ultrabraid)in PRBT applications.Methods: Forty Achilles tendons from bulls were randomly divided into 4 groups(n=10)and cut.The proximal end was fixed with Krackow sutures at the myotendious junction and the distal end was fixed through a coronary canal.Group A used 4 Ethibond suture threads(USP 5)to connect the stumps and group B used 8 Ethibond suture threads(USP 5).Group C used 4 Ultrabraid threads(USP 2)to connect the stumps and group D used 8 Ultrabraid threads(USP 2).The dynamic tensile forces of 20-100 N,20-200 N,20-300 N and 20-400 N were tested using a universal material meter at 0.5 Hz for 250 cycles.After each stage of testing,the gap between stumps was measured with a caliper and the type of suture failure was recorded.Results: After 250 cycles of dynamic tension of 20-100 N,the gaps in the 4 groups were all within the safe range.After 20-200 N,the gap between the four groups was from D to B,C and A.There were significant differences between groups A and B and between groups C and D(P<0.05).After 20-300 N and 20-400 N,the gap between tendons in four groups was all greater than 5mm.After dynamic tension 20-100 N and 20-200 N,there was no suture failure in four groups.After dynamic tension 20-300 N,the suture retention rates of groups A,B,C and D were 0%,80%,60% and 100%,respectively.The difference of suture retention between group A and group B,C and D was statistically significant(P<0.05).There was no significant difference between groups B,C and D(P>0.05).After 20N-400 N,the suture retention rates of groups A,B,C and D were 0%,50%,0% and 70%,respectively.Among them,there was a statistically significant difference in the survival rate between group A and the group B(P<0.05).There was no significant difference between group B and group D between the group A and the C group(P<0.05).Conclusion: By using the calcanean anchoring technique and ultra-strong suture,the PRBT can achieve excellent biomechanical properties.There should be 8 ultra-strong sutures to connect the stumps of Achilles tendon,which can be safely used when using ankle boots and heel pads in the early rapid after surgery.