gms | German Medical Science

Objectives/Interrogation: Current literature supports the idea of joining tendons or tendon grafts by multiple interdigitating weaves, known as the 'Pulvertaft weaves' in proximal reconstruction of tendon grafts to increase the tensile strength. While a greater number of weaves contribute to greater strength of the reconstruction, additional weaves would add to the bulk which inhibits optimal tendon gliding and postoperative rehabilitation. The aim of this study is to investigate the optimal number of weaves on the tensile strength of tendon reconstruction.

Methods: 36 fresh frozen flexor tendons were harvested and divided into 3 groups with 6 specimens each (G1 - 1 weave; G2 - 2 weaves; G3 - 3 weaves). Longitudinal slits were made on the receiving tendon at 90 degrees perpendicular to the previous slit. The tendon graft was delivered through the slits to form the interdigitating weaves. The tendons were reconstructed using 8 anchoring sutures (Ethilon 3/0) placed at regular intervals.

The tensile load of the repaired tendon was measured by a mechanical tester (Instron Model 3343). Firstly, the repairs clamped at each ends and pre-loaded with 5 consecutive cycles of 2.0 N. The specimen was then pulled to failure at a constant strain rate of 20 mm/min. Variables measured were: maximum load, tensile extension at maximum load, ultimate load and time to failure. One-way ANOVA was used to determine the statistical difference between the groups. A high-speed camera was used to record the mechanism of failure.

Results and Conclusions: The mean maximum load for G1 was 75.18N; G2 90.60N, and G3 89.41N; G2 and G3 showed very similar results but these were not statistically significant. The mean tensile extension at maximum load (G2 14.59mm vs G3 15.80mm, p 0.010); ultimate load (G2 50.46mm vs G3 57.72mm, p 0.049); and time to failure (G2 149.9 sec vs G3 173.52 sec, p 0.042) were found to be statistically significant. The modes of failure for all the 18 specimens were suture pull out resulting in gradual failure. One specimen from G2 and G3 demonstrated suture breakage, these were found to have precipitated earlier time to failure.

This study demonstrated that 2-weave tendon grafts were comparable in tensile strength with the 3-weave construct. This suggested that a 2-weave construct could afford sufficient stability for finger and hand rehabilitation following tendon reconstruction. The 2-weave construct is less bulky, which reduces the tendency for tendon adhesion and resistance in gliding.