Augmentation of Rotator Cuff Healing With Orthobiologics

Abstract

The limited regenerative capacity of the tendon-bone enthesis after surgical repair poses a significant challenge to achieving desired clinical outcomes. Biologic augmentation of the repair site has the potential to enhance the biomechanical and histological integrity of the enthesis, leading to lower retear rates and greater patient satisfaction. Platelet-rich plasma, stem cells and bone marrow aspirate concentrate, growth factors, biodegradable or biomimetic scaffolds, and amniotic products have been investigated in preclinical and, in some cases, clinical studies aimed at augmenting tendon-bone healing. Although many of these therapies have achieved some degree of success in improving structural, histological, and clinical outcomes after surgical tendon-bone enthesis repair, none have reliably and consistently lead to clinical improvement. High-quality randomized controlled clinical studies are needed to definitively evaluate the efficacy of these biologic therapies and ultimately determine which, if any, are capable of achieving a tendon-bone repair that is structurally noninferior to the native enthesis before injury.

Figure 1:

Hematoxylin & Eosin (H&E, left) and Safranin O (Saf O, right) stained sections of the native (top) and surgically injured/repaired (bottom) rat rotator cuff tendon-bone enthesis (10x zoom). The four distinct zones of the native H&E-stained enthesis are marked: Bone (B), Mineralized Fibrocartilage (MFC), Unmineralized Fibrocartilage (UMFC), and Tendon (T)³. In the repaired tendons, note that both Fibrocartilage zones are replaced by a disorganized, granular, fibrotic Interface (IF) zone. Evident in the Saf O-stained sections is the lack of parallel chondrocyte organization and proteoglycan content (red) at the repaired enthesis.