Biologic augmentation in rotator cuff repair--should we do it, who should get it, and has it worked?

Rotator cuff tears are a common pathologic entity, and rotator cuff repairs are a frequently performed procedure. Given the high rate of structural failure of repair, biological augmentation of repairs is increasingly important. Biological augmentation primarily enhances the healing response and secondarily provides a mechanical bridge for tension free repair. Understanding biology of tendons and tendon healing aids in determining an optimal environment for repair. The basic principles of rotator cuff repair are aimed at achieving high initial fixation strength of the repair, restoring the anatomic footprint of the cuff tendon, minimizing gap formation, and maintaining mechanical stability until biologic healing occurs. Methods of augmentation come in many different forms and can be categorized by cell type and mechanism of delivery. Cell types include individual growth factors, stem cells, or a combination of both. Vehicles range from in situ delivery, such as microfracture, direct injection, or scaffold materials that are biologic or synthetic.