Bone and joint infections have been a sinister and stubborn disease that has accompanied mankind for thousands of years, and countless medical practitioners have never stopped trying to conquer the disease, yet to this day, bone and joint infections are still considered a formidable enemy by orthopedic surgeons. Some patients have had osteomyelitis since childhood and are still bleeding into their 60s and 70s, so imagine how stubborn it is. Why is chronic osteomyelitis so difficult to treat? Bacteria have a variety of offensive and defensive mechanisms to ensure their production. Bacteria use exotoxins, enzymes, and endotoxins as “chemical weapons” when they attack, just as many predators must kill their prey before they can eat it. The outermost line of defense is the host-produced fibrous membrane and osseous envelope, structures that limit the access or penetration of blood vessels, inflammatory responses, body fluids, and antibiotics to the bacteria; the pus cavity, which has low oxygen tension, few nutrients, and contains debris from necrotic tissue, bacterial toxins, enzymes released from dead inflammatory cells, and dead bone, also has a defensive role Dead bone, endophytes and other foreign matter is a port for bacteria, providing a stable and unchanging base for bacteria, and is an ideal place for bacteria to defend themselves, reproduce and attach; polysaccharide proteins not only help bacteria attach, but also prevent the penetration of phagocytes, antibodies and antibiotics, providing “intimate” protection for bacteria. A thorough understanding of the above individual chemical and mechanical mechanisms of attack and defense explains why chronic osteomyelitis is such a persistent disease. Once the bacteria have entered the tissue, the possibility of infection depends mainly on the environment, or more precisely, the bacteria are not to be feared, but only because of poor blood flow. If the local blood flow is good, even if there is an infection, the body has a defense against the bacteria and the inflammation can subside quickly. The antibiotics put in are also easy to reach the bone lesion site and be effective. The pathological feature of chronic osteomyelitis is the lack of local blood flow, therefore, antibiotics cannot completely treat the inflammation. Although the clinical application of antibiotics is very effective in the treatment of acute osteomyelitis, either oral or intravenous antibiotics are not as effective in chronic osteomyelitis. Due to the destruction of bone tissue lesions in chronic osteomyelitis, necrosis, scarring of surrounding tissues, and lack of local blood flow, antibiotics cannot reach the lesions, which is the reason why osteomyelitis is difficult to treat. The presence of dead bone and dead cavity is the pathological basis of chronic osteomyelitis that persists for a long time and is difficult to be eliminated by both the organism and antibiotics, therefore, the lesions must be removed surgically to improve local blood flow in order for the antibiotics to be effective.