Ex Vivo Biomechanical Assessment of a Novel Multi-Strand Repair of Canine Tendon Lacerations

Abstract

Objective This study aimed to evaluate the effect of increasing the number of suture strands traversing the transection site, level of suture purchase and depth of suture penetrance on the biomechanical properties of repaired gastrocnemius tendons. Study Design Thirty-eight adult cadaveric gastrocnemius tendons were randomized, transected and repaired with either two-, four- or six-strand locking multi-level repair. Tensile loads required to create a 1 and 3 mm gap, yield, peak and failure loads and failure mode were analysed. Significance was set at p < 0.05. Results Mean ± standard deviation yield, peak and failure force for six-strand repairs was 90.6 ± 22.1 N, 111.4 ± 15.2 N and 110.3 ± 15.1 N respectively. This was significantly greater compared with both four-strand (55.0 ± 8.9 N, 72.9 ± 7.8 N and 72.1 ± 8.2 N) and two-strand repairs (24.7 ± 8.3 N, 36.5 ± 6.0 N and 36.1 ± 6.3 N) respectively (p < 0.001). Occurrence of 3 mm gap formation was significantly less using six-strand repairs (p < 0.001). Mode of failure did not differ between groups with all repairs (36/36; 100%) failing by suture pull-through. Conclusion Pattern modification by increasing the number of suture strands crossing the repair site, increasing points of suture purchase from the transection site and depth of suture penetrance is positively correlated with repair site strength while significantly reducing the occurrence of gap formation in a canine cadaveric model. Additional studies in vivo are recommended to evaluate their effect on tendinous healing, blood supply and glide resistance prior to clinical implementation.

Achilles Tendon Rupture Treated with Flexor Digitorum Lateralis Tendon Transposition and Transarticular External Skeletal Fixator in Ouessant Sheep

“…3,4 The strength of the primary repair of the tendon is improved by increasing the number of suture strands crossing the repair, increasing points of suture purchase from the transection site, and depth of suture penetrance. 24,25 This is obtained using locking-loop, three-loop pulley, and Krackow suture patterns. Furthermore, the three-loop pulley is considered to be the suture pattern of choice for rounded-tendon primary repair.…”

Loop modification of the traditional three-loop pulley pattern improves the biomechanical properties and resistance to 3-mm gap formation in a canine common calcanean teno-osseous avulsion model

“…Several human and veterinary studies [18][19][20][21][22] have shown that improvements in tensile strength can be achieved by increasing the number of suture strands or suture loops traversing the tenorrhaphy. As a result, many techniques used for distal extremity tendon repair in humans have led to an increase in pattern complexity and resultant use of multistrand repair patterns.…”

“…As a result, many techniques used for distal extremity tendon repair in humans have led to an increase in pattern complexity and resultant use of multistrand repair patterns. 19,20,22 In a study using an ovine tendon model Al-Qattan et al 20 demonstrated an approximately 2-fold increase in repair site strength when increasing from a 2 to 6 strand repair method. Recent literature has demonstrated similar findings in veterinary studies 21,23 evaluating mid body repair following laceration of canine tendons.…”

“…Our results support the results of prior investigators where increasing the number of strands increased loads required to cause a 3-mm gap. [19][20][21][22]34 Due to the fact that each sequential loop in the 6LP is offset by 60° there is complete engagement of the suture to the tendon for 360° around the total circumference at the enthesis. It is important to realize that the number of suture loops and thus the number of strands crossing the repair is not the only important factor to consider during tendinous repair.…”