A biomechanical comparison of 3 loop suture materials in a 6-strand flexor tendon repair technique

The braided polyblend (FiberWire) suture is recognized for its superiority in tensile strength in flexor tendon repair. The purpose of this study was to compare the biomechanical performance of 3 loop-suture materials used in a locking 6-strand flexor tendon repair configuration: braided polyblend (FiberLoop 4-0), cable nylon (Supramid Extra II 4-0), and braided polyester (Tendo-Loop 4-0). We hypothesized that, using this technique, the braided polyblend suture would give superior tensile strength compared with the other 2 suture materials.

We divided 30 fresh porcine flexor tendons transversely and repaired each with 1 of the 3 suture materials using a modified Lim-Tsai 6-strand suture technique. We loaded the repaired tendons to failure using a materials testing machine and collected data on the mechanism of failure, ultimate tensile strength, gap strength, and stiffness.

Failure mechanisms for the repaired specimens were as follows: the braided polyblend had 50% suture breakage and 50% suture pullout; the cable nylon had 100% suture breakage; and the braided polyester had 80% suture breakage and 20% suture pullout. Specimens repaired with the braided polyblend suture had the highest mean ultimate tensile strength (97 N; standard deviation, 22) and the highest mean gap force (35 N; standard deviation, 7).

This study supports the findings of previous studies showing superior strength of the braided polyblend suture.

We were able to achieve up to 124 N in ultimate tensile strength and 48 N of gap force with this suture in porcine tendons. This gives greater confidence in starting immediate controlled passive or active rehabilitation after repair of flexor tendon injuries.