Biological Augmentation of Rotator Cuff Repair with Endothelial Progenitor Cells

Introduction: Acute and chronic rotator cuff tears represent a substantial clinical burden in our society and remain an unsolved problem in orthopaedics. Despite the evolution of minimally-invasive surgical techniques for rotator cuff repair, including mini-open and arthroscopic approaches, failure of surgically repaired rotator cuff tears to heal continues to represent a significant problem. Estimates of postoperative re-tear rates range from 11-94%, and failure of rotator cuff healing is correlated with inferior clinical outcomes. This has lead to significant research interest in biological strategies for the augmentation of surgical repair, with numerous pre-clinical and clinical studies evaluating a variety of strategies including growth factor supplementation, application of progenitor cells, and the use of extracellular matrices. Despite this, an effective biological strategy for the augmentation of rotator cuff repair remains elusive. Among the strategies being currently investigated, the use of autologous cellbased strategies is of particular interest. However, recent pre-clinical investigation of cell-based strategies employing mesenchymal stem cells (MSCs) has produced disappointing results.