Scaffold and Graft-Based Biologic Augmentation of Rotator Cuff Repair: An Updated Systematic Review & Meta-Analysis of Pre-Clinical and Clinical Studies for 2010-2022.

BACKGROUND: Despite advancements in the surgical techniques of rotator cuff repair (RCR), there remains a high retear rate. Biological augmentation of repairs with overlaying grafts and scaffolds may enhance healing and strengthen the repair construct. This study aimed to investigate the efficacy and safety of scaffold (non-structural) and non-superior capsule reconstruction & non-bridging 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-two studies (level I-IV evidence) were included, with 47 reporting outcomes in animal models and 15 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. Ten of the 15 (66.7%) clinical studies illustrated improvement in postoperative clinical, functional, 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. 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 (OR=0.28, P<0.00001, I-squared=0.11).

CONCLUSIONS: 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.