Knotless anchors offer better prevention of meniscal excursion than knotted anchors: An experimental study of the bovine knee.

OBJECTIVE

Due to the biomechanical importance of the meniscal root ligament, several surgical techniques have been defined in order to treat meniscal root tear. Different application techniques have different levels of difficulty. We aimed to find a stronger and simpler repair technique.

METHODS

Sixteen bovine knee joints were prepared. The posterior root of the medial meniscus was dissected and repaired with one of two different techniques. The knees in group 1 ("knotted group") were repaired with the knotted suture anchor technique, and the knees in group 2 ("knotless group") were repaired using the knotless suture anchor technique. The strength of the repairs was tested biomechanically.

RESULTS

Cyclic loading tests were done. On the 0-20 N one-cycle test, the knotted anchor group's equivalent stiffness average was 5.28 N/mm, and the knotless anchor group's equivalent stiffness average was 5.48 N/mm. The 5-20 N two-cycle test results were 8.29 N/mm for the knotted group and 8.66 N/mm for the knotless group. On the 5-20 N 100-cycle test, the equivalent stiffness averages were 8.59 N/mm for the knotted group and 10.18 N/mm for the knotless group. Elongation was 5.83 mm for the knotted group and 4.86 mm for the knotless group. After performing load-to-failure tests, the failure forces were recorded as 237.83 N for the knotted group and 204.90 N for the knotless group. The failure test elongation values were 26.83 mm for the knotted group and 18.70 mm for the knotless group. The failure energies were 3.87 J for the knotted group and 1.83 J for the knotless group. Except for elongation until failure (p=0.009), there were no significant differences between the two groups tested (p>0.05). The average elongation was significantly less in group 2, showing that the knotless anchor had an advantage, with less meniscal excursion compared to the sutured anchor.

CONCLUSION

Knotless anchors have a mechanical advantage over knotted anchors for preventing meniscal excursion. When thought together with technical simplicity during arthroscopic surgery, knotless anchors could be used safely for the fixation of the meniscal root ligament.