36 January 2009 / Vol 22 No 1 ABSTRACT: The social impact of bone and cartilage pathologies entails high costs in terms of therapeutic treatments and loss of income. As a result, the current research trend includes preventive interventions and therapeutic solutions that can lead to an enhancement of tissue regeneration and the reduction of degenera- tive mechanisms. Many options have been made available to address problems regarding cartilage damage, each with its own advantages and disadvantages. Several stud- ies are currently in progress to clarify some of the questions that remain unanswered about the long- term durability of these procedures and the possible modifications that can be made to achieve better re- sults. Biotechnology is progressing at a rapid pace that al- lows the introductions of several products for clinical application; however, randomized, prospective studies for these innovations should be conducted to validate the safety and efficacy of cartilage regeneration. [J Knee Surg. 2009;22:36-44.] INTRODUCTION According to a study conducted by the World Health Organization, musculoskeletal injuries are the most common cause of severe long-term pain and disability, affecting millions of people worldwide. 59 Accordingly, 2000 to 2010 has been called the “decade of bone and joints” to launch global awareness and promote further research in the prevention, diagnosis, and treatment of joint injuries. The social impact of bone and cartilage pathologies entails high costs through therapeutic treatments and loss of income. In the United States, osteoarthritis medi- cines cost $5.31 billion in 2007, 4 and musculoskeletal conditions including osteoarthritis cost nearly $128 bil- lion per year in direct medical expenses (ie, total joint replacement procedures and loss of income and produc- tion in 2003). 5 For these reasons, the trend of the research is now going toward preventive interventions and therapeu- tic solutions that can lead to an enhancement of tissue regeneration and the reduction of degenerative mecha- nisms. CARTILAGE TREATMENT Hyaline cartilage combines a smooth surface and the ability to withstand an extreme amount of pressure. It is extremely important to reconstruct a perfect surface that will withstand heavy loads. Unfortunately, articular carti- lage lesions, with their inherent limited healing potential, remain a challenging problem for orthopedic surgeons. In the past few decades, surgeons often replaced the ar- ticular surface with expensive and sophisticated implants when articular lesions become full-blown osteoarthritis. However, recent studies have used new orthobiological techniques in cartilage lesions with increasing frequency and effectiveness as a way to regenerate tissue homeo- stasis and delay the progression of osteoarthritis. Growth factors and mesenchymal stem cells have been used suc- cessfully in many medical fields, such as maxillofacial, cosmetic, spine, orthopedic, and general wound healing applications. Biological Approaches for Cartilage Repair Alberto Gobbi, MD Lyndon Bathan, MD The authors are from the Orthopaedic Arthroscopic Surgery Interna- tional Bioresearch Foundation, Milan, Italy. Correspondence: Alberto Gobbi, MD, Orthopaedic Arthroscopic Surgery International Bioresearch Foundation, Via Amadeo 24, 20133 Milano, Italy.