Chronic hepatitis B is feared by all, and the hepatitis B virus is a virus that can easily lead to cirrhosis of the liver and liver cancer. For people who are not yet infected, the hepatitis B vaccine is currently used for prevention. For patients who are already infected and have replication of the virus in their bodies, most of the anti-hepatitis B virus drugs are currently used for long-term treatment to control its replication and destruction. Among the anti-hepatitis B virus drugs, lamivudine, adefovir and entecavir are mostly used. Many patients tend to focus on liver function, two-and-a-half pairs and hepatitis virus replication index in their treatment, thinking that as long as these indicators are controlled, the occurrence of cirrhosis and liver cancer can be avoided or reduced to the greatest extent, but there is a skeletal disease that will slowly occur in a small percentage of these patients. However, there is a skeletal disease that occurs slowly in a small percentage of these patients. Recently, we have come across several such patients, all of whom have been taking adefovir for anti-hepatitis B treatment and gradually developed sore bones and joints all over the body and worsened, basically they did not care about the symptoms of skeletal shutdown pain at first, and some of them would occasionally go to the hospital, basically as common bruises or muscle strain with some painkillers, but not very effective, and after aggravation many hospitals would think of Bone density check, found that the bone density is reduced, then diagnosed as “osteoporosis”, given the corresponding treatment but how not good, so seek medical advice. In fact, these patients are not suffering from osteoporosis, but a disease called “hypophosphatasia chondrodysplasia”. In simple terms, this disease is caused by a rare side effect of the drug adefovir. This disease is characterized by a decrease in bone density, which is characteristic of osteoporosis, but also by a decrease in blood phosphorus and an increase in alkaline phosphatase in the blood, which are not characteristic of osteoporosis. However, unlike osteoporosis, which is a disease in which a large amount of minerals are lost from the bones but the fibrous skeleton of the bones is not destroyed, osteoporosis is a disease in which both minerals and the fibrous skeleton of the bones are lost and destroyed. Therefore, anti-osteoporosis treatment for chondromalacia is ineffective, and oral supplementation with neutral phosphorus combined with phosphorus supplementation is necessary for effective relief and treatment of low phosphorus chondromalacia. Although this disease is caused by the side effects of adefovir, due to the special background of hepatitis B, it is important not to discontinue adefovir immediately when such side effects occur, as this can easily lead to hepatitis B virus mutation and drug resistance, and must be discontinued and changed under the guidance of an infection or hepatology doctor. You must discontinue and change the medication under the guidance of an infection or hepatology doctor. 2, in the use of adefovir for anti-hepatitis B treatment process, in addition to pay attention to the indicators of liver disease, but also need to regularly monitor the blood phosphorus and alkaline phosphatase, once found abnormalities should be dealt with immediately. 3, in the presence of bone and joint pain examination found that the bone density is reduced, do not simplify that is osteoporosis, but also need to pay attention to the possibility of this disease, should be combined with blood calcium phosphorus and alkaline phosphatase and other indicators for a comprehensive judgment. 4, the current treatment of low phosphorus chondromalacia used in neutral phosphorus compound basically can not buy ready-made drugs, only through the chemical reagent store to buy analytically pure potassium hydrogen phosphate and potassium dihydrogen phosphate to prepare their own solution, instead of drinking tea every day, the specific method of preparation should also seek the advice of a professional doctor. 5, in addition to taking neutral phosphorus combination in the treatment, it is also recommended to take alfacalcidol or osteotriol, which can further reduce the loss of phosphorus excretion from the kidneys, so that the effect of phosphorus supplementation better. These need to remind the majority of chronic hepatitis B patients, especially in patients taking adefovir, in the anti-hepatitis B at the same time also pay attention to their bone changes Oh.