Biomechanical evaluation of a novel double rip-stop technique with medial row knots for rotator cuff repair

Abstract

Aims Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots. Methods A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded. Results The mean load to create a 3 mm gap formation in the DRSK and DRS groups was significantly higher than in the SB group. The DRSK group had the highest load to failure with a mean ultimate failure load of 395.0 N (SD 56.8) compared to the SB and DRS groups, which recorded 147.1 N (SD 34.3) and 285.9 N (SD 89.8), respectively (p < 0.001 for both). The DRS group showed a significantly higher mean failure load than the SB group (p = 0.006). Both the DRS and DRSK groups showed significantly higher mean stiffness than the SB group. Conclusion The biomechanical properties of the DRS technique were significantly improved compared to the SB technique. The DRS technique with medial row knots showed superior biomechanical performance than the DRS technique alone.

The Plug-Type Patch Results in Immediate and Postoperative Advantages in Graft-to-Bone Integration for Bridging Massive Rotator Cuff Tears in a Chronic Rabbit Model

“…In immediate evaluations, we demonstrated that the Plug-Pat can provide a significantly larger refreshed contact area between the graft and bone at time zero, which may optimize the healing biology at the repaired graft-bone interface. 23,24,36,37,56 In the green fluorescent protein–bone marrow chimeric rat model, Nakagawa et al 31 reported that the footprint preparation by drilling small bone holes resulted in more bone marrow–derived cells infiltrating the healing interface when compared with the footprint spongialization by exposing the cancellous bone. Similarly, this special tunnel-based “footprint preparation” using bone tunnel with a larger refreshed bone bed contact area in the Plug-Pat may lead to an increased local outflow of stem cells and other cytokines from the bone marrow for better introduction to the healing interface, thus enhancing graft-to-bone healing.…”

“…After biomechanical testing, the width and length of the footprint in the Rect-Pat group, as well as the diameter and depth of the 2 newly fabricated tunnels in the Plug-Pat group, were measured using a vernier caliper (see Appendix Figure A3, available online). 1,56 These parameters were used to calculate the intraoperative refreshing bone bed areas (refreshed contact area between the graft and bone bed) after footprint preparation, which is critical for the graft-bone integration in 2 groups. 31…”