Inlay Scaffold Augmentation of Rotator Cuff Repairs Enhances Histologic Resemblance to Native Enthesis in Animal Studies: A Systematic Review.

ABSTRACT

PURPOSE: To investigate the outcomes of inlay positioned scaffolds for rotator cuff healing and regeneration of the native enthesis after augmentation of rotator cuff tendon repairs in preclinical studies. METHODS: A literature search was performed using the PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature databases according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Preclinical studies reporting on outcomes after inlay tendon augmentation in rotator cuff repair were included. Preclinical study quality was assessed using an adapted version of the Gold Standard Publication Checklist for animal studies. The level of evidence was defined based on the inclusion of clinical analyses (grade A), biomechanical analyses (grade B), biochemical analyses (grade C), semiquantitative analyses (grade D), and qualitative histologic analyses (grade E). RESULTS: Thirteen preclinical studies met the inclusion criteria. Quality assessment scores ranged from 4 to 8 points, and level-of-evidence grades ranged from B to E. Sheep/ewes were the main animal rotator cuff tear model used (n = 7). Demineralized bone matrix or demineralized cortical bone was the most commonly investigated scaffold (n = 6). Most of the preclinical evidence (n = 10) showed qualitative or quantitative differences regarding histologic, biomechanical, and biochemical outcomes in favor of interpositional scaffold augmentation of cuff repairs in comparison to controls. CONCLUSIONS: Inlay scaffold positioning in preclinical studies has been shown to enhance the healing biology of the enthesis while providing histologic similarities to its native 4-zone configuration. CLINICAL RELEVANCE Although onlay positioned grafts and scaffolds have shown mixed results in preclinical and early clinical studies, inlay scaffolds may provide enhanced healing and structural support in comparison owing to the ability to integrate with the bone-tendon interface.