Objective To retrospectively study revisions for infected total hip replacements in 30 cases and discuss the bacteriological characters of the infected total hip replacements,difficulties and strategies in the revision.Methods Thirty revisions of infected total hip replacements were reviewed retrospectively.There were 12 males and 18 females,with mean age of 62.5 years(31-86 years)at revi- sion surgery.Infection was presented one month to four years(mean seven months)after THA operation. The diseases for initial operation included femoral neck fractures in 12 cases,femoral headnecrosis in 11,hip osteoarthritis in five and rheumatoid arthritis in two.Twelve eases were treated by one-stage revi- sion and 18 by two-stage revision.Results Before the revision operation,the hipinfection were diag- nosed by bacterial culture in 18 cases including five with Staphylococcus epidermidis,four with Staphylo- coccus aureus and nine with other bacteria.Bacteriagrowth appeared on the specimens from 23 hip joints during the revision surgery but not on the specimens from seven hip joints.Of 12 one-stage revisions,10 cases were followed for mean 16 months,which showed infectionrecurrence in two eases.Of 18 two-stage revisions,13 cases were followed for mean 20 months,which showed one case with infectionrecurrence. The mean Harris hip score was improved from preoperative 44 to 84 at follow-up.Conclusions 1) The main bacteria in the infected hip are antibiotic resistant Staphylococcus.2)Because the revision op- eration is difficult,careful preparation before revision is important for success.The fresh surgeon should not attempt.3)The revision strategies should vary according to specific status of the cases.The infectionrecurrence rate is lower when using a two-stage revision strategy.4)Application of antibioticbone cement can help improve treatment effect and facilitate functional recovery of the joints.5)The scientific rehabil- itation after operation is very important to functional recovery.