Summary

Animal studies have demonstrated biomechanical enhancement and histological improvement with a diverse spectrum of graft and scaffold constructs. The translation of the enhanced bone-tendon interface into improved functional outcomes has demonstrated biological augmentation of rotator cuff repair as safe and significantly decreasing retear rates in meta-analysis.

Abstract

Purpose

Despite advancements in surgical technique in rotator cuff repair (RCR), poor biological healing and mechanical strength remain significant challenges, contributing to recurrent retear states. Biological augmentation of repairs with overlaying grafts and scaffolds may enhance native tissue regeneration and strengthen integrity at the suture-tendon junction, improving post-operative patient outcomes. This study aimed to investigate the efficacy of scaffold (non-structural) and non-superior capsule reconstruction overlay graft-based (structural) biologic augmentation in RCR, in both pre-clinical and clinical studies.

Methods

This systematic review was performed in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and guidelines outlined by the Cochrane Collaboration. A search of PubMed, Embase, and Cochrane Library from 2010 until 2022 was conducted to identify studies reporting the clinical, functional, and/or patient-report outcomes of at least one biologic augmentation method in either animal models or humans. Methodological quality of included primary studies was appraised using the CLEAR-NPT for randomized control trials and the MINORS criteria for non-randomized studies.

Results

Sixty studies (level I-IV evidence) were included, with 47 reporting outcomes in animal models and 13 clinical studies. Forty-one of the 47 (87.2%) animal-model studies demonstrated biomechanical and histological enhancement with improved RCR load-to-failure, stiffness, and strength. Nine of the 13 (69.3%) clinical studies illustrated improvement in post-operative clinical, functional, and patient-reported outcomes (e.g. retear rate, radiographic thickness and footprint, patient functional scores). No study reported a significant detriment to repair with augmentation and all studies endorsed low complication rates, suggesting no greater complication risk compared to standard repair. A meta-analysis of pooled retear rates demonstrated significantly lower odds of retear in those treated with biologic augmentation of RCR, compared to non-augmented RCR, with low heterogeneity (P<0.0001, I-squared=0.09).

Conclusion

Graft and scaffold augmentation have shown favorable results in both pre-clinical and clinical studies. Of the investigated clinical grafts and scaffolds, acellular human dermal allograft and bovine collagen demonstrate the most promising preliminary evidence in each category, respectively. With a low risk of bias, meta-analysis revealed that biologic augmentation significantly lowered the odds of retear. Although further investigation is warranted, these findings suggest graft/scaffold biologic augmentation of RCR to be safe.