Comparative Evaluation of the Book-Type Acellular Bone Scaffold and Fibrocartilage Scaffold for Bone-Tendon Healing.

Bone-tendon (B-T) healing is a clinical challenge due to its limited regeneration capability. Fibrocartilage regeneration and bone formation at the healing site are two critical factors for B-T healing. Promoting fibrocartilage regeneration and bone formation by tissue-engineering may be a promising treatment strategy. In this study, we innovatively fabricated two kinds of acellular scaffolds from bone or fibrocartilage tissues, namely the book-type the acellular bone scaffold (BABS) and the book-type acellular fibrocartilage scaffold (BAFS). Histologically, the two scaffolds well preserved the native extracellular matrix (ECM) structure without cellular components. In vitro studies showed BABS is superior in osteogenic inducibility, while BAFS has good chondrogenic inducibility. To comparatively investigate the efficacy on B-T healing, the BABS or BAFS were, respectively, implanted into a rabbit partial patellectomy model. Macroscopically, a regenerated bone-tendon insertion (BTI) was bridging the residual patella and patellar-tendon with no signs of infection and osteoarthritis. Radiologically, more new bone was formed at the healing interface in the BABS group as compared with the BAFS or control (CTL) groups (p < 0.05). Histologically, at postoperative week 16, histological scores were significantly better for regenerated fibrocartilage in the BAFS group or BABS group compared with the CTL group, but the BAFS group showed a significantly larger score than the BABS groups (p < 0.05). Biomechanical evaluation indicated a higher failure load and stiffness were shown in the BAFS group than those in the BABS or CTL groups at week 16 (p < 0.05). This study indicated that the BAFS is a more promising scaffold for B-T healing in comparison with the BABS. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1709-1722, 2019.