Medial grasping sutures significantly improve load to failure of the rotator cuff suture bridge repair

Abstract

The suture bridge (SB) transosseous-equivalent rotator cuff repair reduces re-tear rates compared with single-row or other double-row constructs. However, failure rates continue to be high, especially in large and massive tears. The aim of this study was to assess the biomechanical performance of a new SB repair with use of a medial grasping suture compared with the traditional SB repair. Seven matched pairs of sheep infraspinatus tendons were randomly assigned to either SB or suture bridge with grasping suture (SBGS) repair. Each construct was subjected to cyclic loading and then loaded until failure under displacement control in a materials testing machine. Footprint displacement, ultimate load to failure, and mode of failure were assessed. The rotator cuff footprint displacement was less during tensile loading with the addition of the medial grasping suture. The ultimate load to failure was significantly greater for the SBGS repair group than for the SB repair group (334.0N vs 79.8N). The mode of failure was the tendon pulling off the footprint in all cases (type 1 tear). There were no failures in which the tendon tore at the medial row of anchors, leaving part of the tendon still on the footprint (type 2 tear). The addition of a medial grasping suture significantly improved the ultimate load to failure and reduced the footprint displacement of the SB rotator cuff repair in a biomechanical model.