Optimum suture material for locking technique in tendon repair: effects of suture friction in mobilization.

BACKGROUND: The 2-strand side-locking loop technique allows secure locking formation easily, yielding maximum tensile force. However, not all suture materials are suitable for this technique.

METHODS: The bovine gastrocnemius tendons were transected and repaired end-to-end by the side-locking loop technique using USP2 braided polyblend, braided polyester, monofilament nylon, braided nylon, or monofilament absorbable polydioxanone sutures. A repetitive loading protocol from 10N to 100N was used, and the loading was repeated 10,000 times. In ruptured samples during the repetitive loading test, the number of loading was recorded. In samples which did not rupture, the ultimate tensile strength was measured after repetitive loading. After testing, ruptured sutures were examined microscopically. For comparison of ultimate tensile strength before and after repetitive loading, we performed a one-time loading test on samples which did not undergo the repetitive loading.

FINDINGS: With monofilament nylon, braided nylon, or monofilament absorbable polydioxanone, suture rupture occurred during repetitive loading. In contrast, no suture rupture occurred with braided polyblend or braided polyester. Microscopic observation showed abrasion of the surface in braided polyester, though the friction effects were not seen with braided polyblend. The mean ultimate tensile strength before and after repetitive loading was 395N and 399N, respectively, for braided polyblend. For braided polyester, they were 208N and 174N, respectively.

INTERPRETATION: Braided polyblend suture material has an excellent resistivity to friction and is suitable for the side-locking loop technique.