From March 2000 to March 2003,15 cases of post internal fixation of fractures and arthroplasty infection were selected from Department of Traumatic Orthopedics,Tianjin Hospital,including 6 males and 9 females.The average age of re-operation was 56 years old.The average time from the primary surgery to diagnosis of infection was 0-19 months.Of the 15 cases,4 of arthroplasty infection underwent prosthesis extraction and temporary fixation with bone cement containing antibiotic and underwent another arthroplasty 6 months later.Of 11 cases of infection following internal fixation,the internal fixation was effective in 2 cases,and the fixation was removed after fracture healing,and ineffective in 9 cases.The fixation was removed primarily and focus of infection was cleared,lavaged with antibiotic solution,and another internal fixation was performed.The pus samples of 15 cases showed positive.Eleven cases(73.3%) had chronic infection including 9 occurring following fracture fixation and 2 following arthroplasty.Four cases(26.7%) had acute infection,including 2 occurring following arthroplasty and 2 following fracture fixation.No infection caused by blood circulation was found.The Gram-positive bacteria,staphylococcus aurens,staphylococcus epidermidis,and enterococcus occupied the most part of the infections in spite of the location and type of the infections,and Gram-positive bacteria-staphylococcus aurens was the most common.The order of the antibiotics sensitivity was Vancomycin,Rifampicin,Gentamicin,and Cephazoline.In addition,antibiotics sensitivity was varied in different infections.In samples of 15 cases,2 cases were sensitive to two bacteria at the same time following fracture fixation.The staphylococcus aurens,staphylococcus epidermidis,and enterococus are the high risk of injection following internal fixation of fractures and arthroplasty.The sensitive antibiotics and long-term medication are effective methods to treat the infection.