Biomechanical Comparison of Lateral Meniscus Radial Tear Repair Patterns Using Rebar Sutures

There is an opportunity to implement improved techniques for the repair of radial meniscus tears; previous studies have shown a benefit to the addition of rebar or "ripstop" sutures parallel to the tear, forming "hashtag constructs" to strengthen the repair of radial meniscus tears. Studies have not directly compared different types of rebar constructs.

The study purpose is to evaluate the biomechanical properties of different suture repair patterns for lateral meniscus tears, including patterns with and without rebar sutures, as well as all-inside and capsule-based constructs. It was hypothesized that the patterns with reinforcing rebar sutures will have a significantly higher load to failure (N).

Controlled laboratory study.

A total of 68 fresh-frozen lateral human menisci were randomized into 8 groups in 2 rounds of testing. The first round compared rebar and nonrebar suture constructs: 2 simple repairs (double horizontal [DH], cross-stitch [CS]), 1 "hashtag" construct with 2 reinforcing rebar-type sutures parallel to the tear and 2 sutures crossing the tear (all-inside rebar 1 [AIR1]), and an experimental hybrid construct (oblique box [OB]). The second round focused on 4 rebar suture repair constructs that included the box-type "hashtag" suture repair, comparing all-inside and capsule-based repairs: the same all-inside rebar 2 (AIR2) construct as in round 1, 1 all-capsule rebar (ACR) construct with knots tied on the lateral surface, and 2 combined all-inside and capsule-based rebar constructs (combined rebar 1 [CR1] and combined rebar 2 [CR2]). The repaired menisci underwent cyclic loading and load-to-failure testing. Ultimate failure load data were analyzed using analysis of variance testing to compare multiple groups, along with Tukey-adjusted P values for pairwise testing.

In the first round, the rebar suture construct (AIR1) sustained a higher ultimate load to failure than the other 3 constructs, at 168.6 N, compared with DH (60.3 N), CS (58.2 N), and OB (102.5 N) (analysis of variance P < .001, pairwise P < .001, P < .001, and P < .002, respectively). In the second round, there was no significant difference in mean ultimate failure load among the 4 rebar constructs, with AIR2 (149.7 N), ACR (148.9 N), CR1 (133.7 N), and CR2 (161.7 N) (P = .596). In pairwise testing, all of the rebar suture constructs (AIR1, AIR2, ACR, CR1, CR2) failed at significantly higher ultimate failure load when compared with the nonrebar suture repair constructs (DH, CS) (P≤ .001 for each).

Our cadaver study demonstrated that in a model of lateral meniscus radial tear repair, constructs using rebar sutures parallel to the tear provided reinforcement for the sutures spanning the tear and resulted in a higher load to failure when compared with nonrebar suture repair constructs.

Surgeons should consider adding parallel rebar sutures to their suture constructs when repairing radial tears arthroscopically to improve the strength of the construct, while maintaining flexibility for various techniques.