How close are we to having structure-modifying drugs available?

This article describes what structure modification is, explains the distinctions among preventing, retarding, stopping, and reversing disease, and suggests approaches that might be clinically meaningful. It discusses whether any evidence suggests it is possible to modify disease and whether the current focus on cartilage is appropriate. It considers the methodologic approaches and the obstacles to demonstrating efficacy of these agents in clinical trials. The authors hope that at the end of this narrative review the reader will appreciate the complexities of this rapidly evolving field and of the development of disease-modifying drugs for osteoarthritis drugs.