Abstract: Chronic osteomyelitis is a long-term and persistent inflammation of the periosteum, bone and bone marrow caused by pathogenic bacteria, and is one of the most common chronic complications in orthopedics. In recent years, due to the extensive formation of bacterial biofilms, the pathogenesis of chronic osteomyelitis has become more complex, and inflammation is often not defended by the host immune system, and recurs, resulting in severe bone destruction and then disability of the affected limb in the later stage of infection. At present, the clinical treatment of this disease is mainly antibiotic combined with surgical debridement. However, the pathophysiological changes of chronic osteomyelitis hinder the penetration of antibiotics and make it difficult to reach the lesion site, and at the same time, due to the gradual severity of antibiotic multi-drug resistance, it also increases the difficulty of treatment of chronic osteomyelitis. Therefore, there is an urgent need to explore a new treatment method that can fight infection. This article reviews the etiology, pathogenic mechanism, refractory factors and the latest progress in the treatment of chronic osteomyelitis, focusing on the advantages of the new photodynamic therapy in the resistance to drug-resistant bacteria infection combined with the latest research results in chronic osteomyelitis.

Key words: chronic osteomyelitis, biofilm, antibotic resistance, photodynamic therapy