Biomechanical Evaluation Comparing Pulvertaft Weave and Side-to-Side Tenorrhaphy Using Porcine Tendons

Abstract

Background: Pulvertaft Weave (PTW) is an established method of tenorrhapy in tendon transfers. Previous studies have suggested that a Side-to-Side (STS) tenorrhapy is easier to perform has the same advantages and has greater load to failure, ultimate load and stiffness compared to PTW. However, there is insufficient data comparing behaviour of STS and PTW during cyclical loading. The aim of this study is to compare these two methods in terms of creep after cyclic landing. Methods: Fresh porcine flexor digitorum tendons were used. Ten tendon PTW and ten STS repairs were performed. Cross sectional diameter was measured. The tendon repairs were tested by applying tension up to 25N for 100 cycles, followed by tension up to 75N for 100 cycles, followed by loading to failure. Force-displacement data was used to determine the creep of the repaired tendon. Results: All tendons survived 100 cycles of loading at 25N. After 1 cycle of loading, the mean cyclic creep in the PTW group was almost 3 mm larger than in the STS group (p = 0.046). After 100 cycles, the mean cyclic creep in the PTW group was 4.4 mm larger (p = 0.008). The cyclic creep rate was significantly larger in the PTW group (p < 0.001). All STS but only four PTW repairs survived after cyclic loading at 75N (p = 0.01). After 1 cycle and 100 cycles, mean creep of the surviving PTW samples was almost 7 mm (p = 0.006) and almost 9 mm (p = 0.004) larger than the STS group. The mean load to failure was four times larger in the STS group than the PTW group (p = 0.004). Conclusions: STS repairs have a significantly smaller permanent elongation after cyclic loading at 25N and 75N, a significantly smaller cyclic creep rate, require a significantly larger load to fail. This implies that STS repairs are less likely to elongate after cyclic loading and can withstand greater loads. These properties can be valuable in allowing patients to commence mobilisation immediately after surgery.