Novel flat and wide meniscal repair material improves the ultimate load of knot breakage in a porcine trans-capsular meniscal repair model

BACKGROUND In the meniscal repair procedures, a high ultimate load capacity and low cyclic creep at the repair site are favorable and lead to good biological incorporation of the tear site after surgery. Previous biomechanical tensile tests of the meniscal sutures have identified the suture knot as the weakest point. We hypothesized that the strength of a suture knot depends on the suture shape, and therefore, we compared three differently shaped suture materials composed of the same material and quantity per length. The purpose of this study was to determine whether a novel flat and wide repair material (FWRM), which consists of braided multi-threads that are cross-sectionally flat and wide, improves the ultimate load of knot breakage in a biomechanical experiment using a porcine trans-capsular meniscal repair model. METHODS Eighteen fresh-frozen porcine knees (n = 6 in each group) were used. A longitudinal tear in the middle segment of the medial meniscus was created and repaired with a trans-capsular inside-out method using the following suture materials: No. 2-0 braided polyester conventional suture, hollow suture, and FWRM. After the separation of the inner segment of the meniscus with leaving, the suture stability of the repaired menisci was biomechanically analyzed with a video camera system for widening after a cyclic load between 5 and 20 N was applied 300 times. Ultimate failure load and stiffness at 5 mm/ min were also analyzed. RESULTS We found no significant difference in suture widening after cyclic load tests [conventional suture, mean 0.51 mm (S.D. 0.39 mm); hollow suture, mean 0.23 mm (S.D. 0.11 mm); and FWRM, mean 0.54 mm (S.D. 0.08 mm)]. The failure mode in all specimens was knot breakage. Compared with those of the other groups, the ultimate failure load of FWRM was statistically significantly higher in the load-to-failure tests (conventional suture, mean 58.8 N [S.D. 8.25 N]; hollow suture, mean 79.4 N [S.D. 10.2 N]; and FWRM, mean 97.4 N [S.D. 3.65 N]; p < 0.05). CONCLUSION FWRM improves the ultimate load of knot breakage without altering stability. This material may contribute to safe and stable meniscus repair.