A Critical Review of Commercial Collagen-Based Scaffolds in Bone Regeneration: Functional Properties and Clinical Evidence from Infuse® Bone Graft

Abstract

This review article provides a comprehensive evaluation of Infuse^® and InductOs^®, two ground-breaking recombinant human Bone Morphogenetic Protein-2 (rhBMP-2)-based bone graft products, focusing on their tissue-level regenerative responses, clinical applications, and associated costs. Preclinical and clinical studies demonstrate that rhBMP-2 induces strong osteoinductive activity, effectively promoting mesenchymal stem cell differentiation and vascularized bone remodeling. While generally well-tolerated, these osteoinductive effects are dose-dependent, and excessive dosing or off-label use may result in adverse outcomes, such as ectopic bone formation or soft tissue inflammation. Histological and imaging analyses in craniofacial, orthopedic, and spinal fusion models confirm significant bone regeneration, positioning rhBMP-2 as a viable alternative to autologous grafts. Notably, advances in delivery systems and scaffold design have enhanced the stability, bioavailability, and targeted release of rhBMP-2, leading to improved fusion rates and reduced healing times in selected patient populations. These innovations, alongside its proven regenerative efficacy, underscore its potential to expand treatment options in cases where autografts are limited or unsuitable. However, the high initial cost, primarily driven by rhBMP-2, remains a critical limitation. Although some studies suggest overall treatment costs might be comparable to autografts when factoring in reduced complications and operative time, autografts often remain more cost-effective. Infuse^® has not substantially reduced the cost of bone regeneration and presents additional safety concerns due to the rapid (burst) release of growth factors and limited mechanical scaffold support. Despite representing a significant advancement in synthetic bone grafting, further innovation is essential to overcome limitations related to cost, mechanical properties, and controlled growth factor delivery.

Keywords: Infuse®/InductOs®; bone regeneration; collagen scaffold; recombinant human BMP-2 (rhBMP-2).

Figure 1

Schematic representation of bone tissue’s composition and regeneration. Bone consists of specialized cells (osteoprogenitor cells, osteoblasts, osteoclasts, and osteocytes) embedded in an extracellular matrix of collagen, hydroxyapatite, and water, which provides structural support and regulates signaling. Reprinted from Ref. [15].

Figure 2

Schematic illustration of tissue-level response to rhBMP-2-based bone grafts.

Figure 3

Medtronic’s Infuse/InductOs Bone Graft’s applications. Adapted from Ref. [47]. Adapted from Ref. [48].

Figure 4

(A) The component and LT-Cage parts of the Infuse Bone Graft medical device. (B) Schematic illustration of the LT-Cages enclosing the Infuse Bone Graft in spinal fusion surgical procedure and (C) postoperative anteroposterior radiograph. Reprinted with permission from Ref. [25]. Copyright 2003 Lippincott Williams & Wilkins. Adapted from Ref. [53]. Adapted from Ref. [54].

Figure 5

Schematic illustration of the maxillary sinus floor augmentation enclosing the Infuse Bone Graft component and implant placement. Reprinted with permission from Ref. [83]. Copyright 2009 Elsevier.