In a consecutive retrospective study of 1500 total hip replacements, analysis of cultures taken at the time of operation revealed that positive cultures obtained in primary arthroplasties are not significant. No statistical difference could be demonstrated between primary and revision arthroplasty cultures as related to joint infection, but on the basis of other clinical studies and the higher incidence of positive cultures in revision arthroplasties, it is believed that these cultures should be treated vigorously. Further studies are being carried out to help clarify the role of prophylactic antibiotics in hip replacement operations in the prevention of post-operative hip joint infection. Antibiotic therapy for the treatment of potentially contaminated hips is also being reviewed. Such studies must be performed over a long term period.