Properties of Cartilage–Subchondral Bone Junctions: A Narrative Review with Specific Focus on the Growth Plate

Objective The purpose of this narrative review is to summarize what is currently known about the structural, chemical, and mechanical properties of cartilage-bone interfaces, which provide tissue integrity across a bimaterial interface of 2 very different structural materials. Maintaining these mechanical interfaces is a key factor for normal bone growth and articular cartilage function and maintenance. Materials and Methods A comprehensive search was conducted using Google Scholar and PubMed/Medline with a specific focus on the growth plate cartilage–subchondral bone interface. All original articles, reviews in journals, and book chapters were considered. Following a review of the overall structural and functional characteristics of the physis, the literature on histological studies of both articular and growth plate chondro-osseous junctions is briefly reviewed. Next the literature on biochemical properties of these interfaces is reviewed, specifically the literature on elemental analyses across the cartilage–subchondral bone junctions. The literature on biomechanical studies of these junctions at the articular and physeal interfaces is also reviewed and compared. Results Unlike the interface between articular cartilage and bone, growth plate cartilage has 2 chondro-osseous junctions. The reserve zone of the mature growth plate is intimately connected to a plate of subchondral bone on the epiphyseal side. This interface resembles that between the subchondral bone and articular cartilage, although much less is known about its makeup and formation. Conclusion There is a notably paucity of information available on the structural and mechanical properties of reserve zone–subchondral epiphyseal bone interface. This review reveals that further studies are needed on the microstructural and mechanical properties of chondro-osseous junction with the reserve zone.