Stability of Double-Row Rotator Cuff Repair Is Not Adversely Affected by Scaffold Interposition Between Tendon and Bone

Background: Rotator cuff reconstructions may be improved by adding growth factors, cells, or other biologic factors into the repair zone. This usually requires a biological carrier (scaffold) to be integrated into the construct and placed in the area of tendon-to-bone healing. This needs to be done without affecting the constructs mechanics. Hypothesis/Purpose: The hypothesis was that scaffold placement, as an interposition, has no adverse effects on biomechanical properties of double-row rotator cuff repair. The purpose of this study was to examine the effect of scaffold interposition on the initial strength of rotator cuff repairs. Study Design: Controlled laboratory study. Methods: Twenty-five fresh-frozen shoulders (mean age: 65.5 +/- 8.9 years) were randomly assigned to 5 groups. Groups were chosen to represent a broad spectrum of commonly used scaffold types: (1) double-row repair without augmentation, (2) double-row repair with interposition of a fibrin clot (Viscogel), (3) double-row repair with interposition of a collagen scaffold (Mucograft) between tendon and bone, (4) double-row repair with interposition of human dermis patch (ArthroFlex) between tendon and bone, and (5) double-row repair with human dermis patch (ArthroFlex) placed on top of the repair. Cyclic loading to measure displacement was performed to 3000 cycles at 1 Hz with an applied 10- to 100-N load. The ultimate load to failure was determined at a rate of 31 mm/min. Results: There were no significant differences in mean displacement under cyclic loading, slope, or energy absorbed to failure between all groups (P = .128, P = .981, P = .105). Ultimate load to failure of repairs that used the collagen patch as an interposition (573.3 +/- 75.6 N) and a dermis patch on top of the reconstruction (575.8 +/- 22.6 N) was higher compared with the repair without a scaffold (348.9 +/- 98.8 N; P = .018 and P = .025). No significant differences were found for repairs with the fibrin clot as an interposition (426.9 +/- 103.6 N) and the decellularized dermis patch as an interposition (469.9 +/- 148.6 N; P = .73 and P = .35). Conclusion: Scaffold augmentation did not adversely affect the zero time strength of the tested standard double-row rotator cuff repairs. An increased ultimate load to failure was observed for 2 of the augmentation methods (collagen patch as an interposition and decellularized dermis patch on top of the reconstruction) compared with the nonaugmented repairs. Clinical Relevance: Scaffolds intended for application of growth factors or cellular components in a repair situation did not adversely jeopardize the stability of the operative construct.