Stem Cell- and Growth Factor-Based Regenerative Therapies for Avascular Necrosis of the Femoral Head
Lars Rackwitz, Lars Eden, Stephan Reppenhagen, Johannes C Reichert, Franz Jakob, Heike Walles, Oliver Pullig, Rocky S Tuan, Maximilian Rudert, and Ulrich Nöth
Osteonecrosis or avascular necrosis (AVN) is defi ned as a pathologic process that results from a critical reduction of blood supply to the bone and elevated intraosseous pressure. Although the pathogenic process is poorly understood, osteonecrosis is the fi nal common pathway of traumatic and non-traumatic insults and compromises the already precarious circulation of the femoral head. Femoral head ischemia subsequently leads to the death of bone marrow and osteocytes and usually results in the collapse of the necrotic segment . AVN is a debilitating disease that usually leads to osteoarthritis of the hip joint in young adults. The disease prevalence is unknown, but estimates indicate that 10,000 to 20,000 new cases are diagnosed in the US each year. Furthermore, it is estimated that 5% to 18% of the more than 500,000 total hip arthroplasties performed annually are related to advanced AVN . Joint-preserving techniques such as core decom pression, avascular or vascularized bone graft ing, and various femoral osteotomies are most promising in early stages of AVN – Association Research Circulation Osseous (ARCO) stage I and II – with preserved structural integrity of the subchondral plate . The structural collapse of the osteonecrotic segment (ARCO stage III and IV) indicates the progressive course of the disease, and total hip replacement is inevitable in most cases in the long term [1,3].