RESUMO
Objective: To compare the biomechanical properties of two ultra-strong sutures and suturing methods in panda rope bridge technique (PRBT) application, and provide guidance for clinical selection of suture threads and suture methods. Methods: Forty Achilles tendons from bulls were randomly divided into 4 groups ( n=10) and transected at the 4 cm proximal to the tendon insertion. Groups A and B used Ethibond sutures (USP 5), the proximal end was fixed at the myotendious junction with Krackow sutures and the distal end was fixed through a calcaneus canal. Groups A and B had 4 and 8 threads through the stump plane, respectively. Groups C and D used Ultrabraid sutures (USP 2), the proximal end was fixed at the myotendious junction with Krackow sutures and the distal end was fixed in the calcaneus with two anchors. Groups C and D had 4 and 8 threads through the stump plane, respectively. The dynamic tensile forces of 20-100, 20-200, 20-300, and 20-400 N were tested respectively by using a dynamic tensile testing machine 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 dynamic tensile forces of 20-100 N and 20-200 N, the gaps of the four groups arranged from small to large were groups D, B, C, and A. The differences between groups A and B and groups C and D were significant ( P0.05). After dynamic tensile forces of 20-400 N, the suture retention rates of groups A, B, C, and D were 0, 50%, 0, and 70%, respectively. There were significant differences between groups A and B and groups C and D ( P<0.05). Conclusion: Repairing Achilles tendon rupture via PRBT with 8 ultra-strong sutures through the stump plane can meet the mechanical requirements for walking by using ankle boots and heel pads in the early accelerated rehabilitation after operation.