Optimizing the Double-Row Construct: An Untied Medial Row Demonstrates Equivalent Mean Contact Pressures in a Rotator Cuff Model

Abstract

Background: The merits of a double-row rotator cuff repair (RCR) construct are well-established for restoration of the footprint and lateral-row security. The theoretical benefit of leaving the medial row untied is to prevent damage to the rotator cuff by tissue strangulation, and the benefit of suture tape is a more even distribution of force across the repair site. These benefits, to our knowledge, have not been evaluated in the laboratory. Hypothesis: Leaving the medial row untied and using a suture bridge technique with suture tape will offer more even pressure distribution across the repair site without compromising total contact force. Study Design: Controlled laboratory study. Methods: A laboratory model of RCR was created using biomechanical research-grade composite humeri and human dermal allografts. The pressure distribution in a double-row suture bridge repair construct was analyzed using the following testing matrix: double-loaded suture anchors with the medial row tied (n = 15) versus untied (n = 15) compared with double-loaded suture tape and anchors with the medial row tied (n = 15) versus untied (n = 15). A digital pressure sensor was used to measure pressure over time after tensioning of the repair site. A multivariate analysis of variance was used for statistical analysis with post hoc testing. Results: The total contact force did not significantly differ between constructs. The contact force between double-loaded suture anchors and double-loaded suture tape and anchors was similar when tied ( P = .15) and untied ( P = .44). An untied medial row resulted in similar contact forces in both the double-loaded suture anchor ( P = .16) and double-loaded suture tape and anchor ( P = .25) constructs. Qualitative increases in focal contact pressure were seen when the medial row was tied. Conclusion: An untied medial row did not significantly affect the total contact force with double-loaded suture anchors and with double-loaded suture tape and anchors. Tying the medial row qualitatively increased crimping at the construct’s periphery, which may contribute to tissue strangulation and hinder clinical healing. Qualitative improvements in force distribution were seen with double-loaded suture tape and anchors. Clinical Relevance: Both tied and untied medial rows demonstrated similar pressures across the repair construct.